cable

Overcurrents may lead to critical temperatures in cable systems. Fuses can protect the cable insulation from damage. As the classically used melting fuses cannot fulfill the growing requirements concerning diagnosis, reset behavior, or fail safety, electronic fuses based on power transistors are more and more introduced in modern systems. As reliable temperature measurements are complex, the electronic fuses are often controlled by the electrical currents flowing through the semiconductor by, e.g., a microcontroller. On the microcontroller the cable temperature is estimated from the current based on an electrothermal cable model. When the temperature exceeds a given threshold the transistor interrupts the current flow. Therefore, accurate and computationally simple thermal cable models are necessary. Complex numerical solutions are inappropriate. For single wire cables several calculation methods are known already, for arrangements of several wires with insulation these methods are not accurate enough. This article presents an analytical thermoelectric calculation method for multiconductor cable arrangements consisting of several identical single wire cables. An approach for the determination of important model parameters is presented and the final model is validated for a power over data line application. The model is exemplarily applied for calculating the temperature developments and ampacities in cable bundles consisting of a different number of cables and for the comparison between a solid and a stranded cable.

The thermodynamic model of work of the loaded cable line is presented. The received mathematical ratio allows to define the maximum allowed current loadings of the cable line in the form of a single-core cable product with the single-layer isolation depending on material and thickness of layer of isolation. It is constructed dependences of the maximum allowed current for a single-core wire of a certain section with one layer rubber (or polyvinilchloride) isolation from insulation layer thickness at various temperatures of the environment and the coefficients of the heat conductivity.

The characteristics of power high-voltage cables differ from the characteristics of ordinary overhead lines. When wind or solar power plants are connected to high-voltage power cables with cross-linked polyethylene insulation, the electrical capacity of which is greater compared to the capacity of an equivalent overhead line, resonant a wide frequencies range arise. This causes a change in the active resistance and inductance of the current-conducting core and the cable as a whole and leads to a change in the wave parameters of power cables with polymer insulation in a wide frequency range. A generalized method of determining the wave parameters of single-core high-voltage power cables based on the determination of active resistance, inductance, capacitance, and active insulation conductivity in a wide frequency range is presented. The methodology is based on the numerical calculation of active resistance and inductance, taking into account the skin effect and the effect of the proximity of the magnetically connected circuits of the conductive core and the metal screen of the power cable. The electric capacity, the tangent of the dielectric loss angle and the active conductivity of the three-layer composite system are determined taking into account the thickness and frequency dependences of the electrophysical parameters of the semiconductor screens. It has been proven that wave resistance is an individual characteristic of power cables and is determined by the cross-section of the current-conducting core, the electro-physical properties of the three-layer electrical insulation system, and the thickness of their components. The influence in the high-frequency range of the tangent of the dielectric loss angle on the attenuation coefficient of electromagnetic energy in power cables of the voltage class of 110 kV is shown. Emphasis is placed on the need to create a database of electro-physical characteristics and thickness of semiconductor screens of power cables from manufacturers. The proposed method has important practical significance in determining the wave parameters of power cables at the stage of manufacture and operation.

… Ensuring effective sheath bonding holds paramount importance within underground single-core cable systems, as a misjudged selection can precipitate cable failures or jeopardize …

In order to indirectly calculate the core temperature of a cable joint, an equivalent transient thermal circuit model of single-core cable joint by considering axial heat dissipation is proposed. Firstly, the temperature field of the middle joint of a 110 kV single-core cable is calculated by finite element method. Based on the heat dissipation path of the core, an improved equivalent thermal circuit model is proposed. The axial heat dissipation of the cable joint core is simplified to a thermal resistance and the temperature rise of the cable body core, the temperature calculation of the cable joint transient process is realized. Compared with the results of finite element simulation, the steady-state temperature errors of the thermal circuit model are within 1 °C, while the maximum temperature errors of the transient process shall not exceed 3 °C, which proves the validity of the model. This method can provide reference for temperature inversion and the dynamic current-carrying capacity prediction of cable joints.

… conductor radius and conductor-to-cable center dimension for common-enclosure gas-insulated cables … for three-core belted cables and verifies CGIC cable parameters using FEMM, …

The purpose of this paper is to propose and apply the correct formula for the eddy-current loss factor for the case of three single-core cables in trefoil formation with metallic screens and armourings bonded and earthed at one end. This metallic screen bonding design is contrasted to the design where metallic screens and armourings are bonded and earthed at both ends, that is, the eddy-current loss factor is contrasted to the circulating-current loss factor. Ampacity calculations are carried out for 12 different underground lines with power cables of the type Cu/XLPE/CTS/PVC/AWA/PVC 1/C 19/33 kV (BS 6622), assuming that the 33 kV cables are installed directly in the soil without drying out. The ampacity is calculated analytically in accordance with IEC 60287-1-1 and IEC 60287-2-1, and numerically in accordance with IEC TR 62095. The numerical calculations are carried out to verify the accuracy of the proposed formula using the finite element method (FEM) in COMSOL 4.3. A validation of the proposed formula is conducted based on the manufacturer's technical data for the considered cables. The calculated ampacity values determined the incompleteness of the current IEC formula for the eddy-current loss factor, and verified the accuracy of the proposed one.

The circulation current of sheath and armor of single-core submarine cable are important factors affecting its safe operation. In this paper, the impedance matrix model of single-core submarine cable is established for the insulation damage fault caused by heating at the grounding position of a 220kV submarine cable in a wind farm. Using the electromagnetic transient analysis software ATP-EMTP, the effects of resistivity and permeability on impedance matrix and circulating current were analyzed. Through the analysis, the cause of damage accident was found and suggestions were made for the operation and maintenance of the submarine cable.

The grounding circulation current of the sheath and armour of single‐core AC submarine cables is high during operation, which can easily cause insulation damage and faults. Traditional methods that only monitor the amplitude of grounding circulation current make it difficult to detect defects in the cables, so further research is needed on the mathematical mechanism and detection methods of grounding circulation current. A mathematical model for the capacitance and impedance coupling of a single‐core submarine cable was established, and the influence of factors such as active power, length of armour stripping section, armour resistivity, armour magnetic permeability and grounding resistance on the grounding circulation current was analysed. A method for identifying abnormal grounding circulation current of submarine cables based on the combination of amplitude and phase was proposed.

Partial discharge (PD) has a well-established relationship with the lifespan of power cables. This paper has been treated the polyvinyl chloride (PVC) with specified nanoparticles for enhancing dielectric degradation and reducing partial discharge current to extending lifespan of power cables. It has been succeeded to creation new polyvinyl chloride nanocomposites that have been synthesized experimentally via using solution-gel (SOL-GEL) technique and have high featured electric and dielectric properties. The validation of nanoparticles penetration inside polyvinyl chloride during synthesis process have been constructed and tested via scanning electron microscope (SEM) images. The partial discharge current mechanisms in polyvinyl chloride nanocomposites have also been simulated in this work by using MATLAB® software. This paper has explored the characterization of partial discharge current for variant void patterns (air, water, rubber impurity) in polyvinyl chloride nanocomposites insulations of power cables to clarify the benefit of filling different nanoparticles (Clay, MgO, ZnO, and BaTiO3) with varied patterns inside power cables dielectrics. A comparative study has been done for different partial discharges patterns to propose characterization of partial discharges using nanoparticles of appropriate types and concentrations.

… To enhance the performance of cable fault location, the principles of two-terminal traveling … Firstly, the cable model derived from the theory of wave propagation in multi-conductor …

When the EMF passes through various materials filling the inclusion, the absorption of wave energy by these substances is observed. Based on the simulation carried out using the COMSOL program, an EMF analysis was performed at the interface of dielectric media between spherical micro-inclusion and the main insulation. It is shown that in solid dielectrics, conductors, EMF absorption is significant. If a wave meets any conductor, then most of its energy is absorbed by it. The presence of heterogeneities (defects) in the insulation at the insulation - inhomogeneity interface causes jumps in the electric field strength ε1/ε2, ε 2/ε3. The simulation and analysis of the electric field strength distribution in the defect region were carried out and it was found that with increasing Sdef, the amplitude of the magnetic induction surge (B) at the first boundary of the defect increases. With increasing Sdef. the depth of the induction failure (B) increases. However, while maintaining the overall picture, the values of dips with different types of filling inclusions are different: – the greatest gradient is observed when filled with water, the smallest when filled with carbon plus cross-linked polyethylene (C + XLPE). Thus, it can be a diagnostic parameter of the quality of the insulation of the PC. The results of the work are of interest in solving a complex of problems related to various aspects of electromagnetic compatibility and reliability of functioning of electric power systems.

… cables are widely used today, while the comparison of thermal degradation behavior between PVC cable insulation … -flame-retardant PVC cable insulation materials were studied using …

This paper investigates the impact of earth continuity conductor (ECC) placement in duct banks for triangular and flat configurations of three-phase single-core underground cables …

… of stainless-steel cores due to overcurrent change in … multi-4-core tube with a glass-coloured insulating material and determined the applicability of the isolated MCTs as electrical cable…

Aircraft electrification yields the next generation of aircraft, such as more electric aircraft (MEA) and all electric aircraft (AEA). These aircraft require high-power-density and low-system-mass electric power systems (EPSs). To this end, the voltage of the system must be enhanced to reach medium voltage (MV) levels in a few kilovolt ranges. However, using MV EPS for aircraft exacerbates the challenges of designing aircraft cables, such as arc and arc tracking, partial discharges (PDs), and thermal management. In this article, several novel multilayer-based insulation systems for MVDC power cables are proposed to resolve aircraft cables’ challenges while maintaining low weight and size. The proposed cables are thermally and electrically analyzed and compared to cable systems designed based on IEC60502 and AS50881 standards. We use a coupled electrical–thermal-fluid flow dynamic model for simulations, where all possible heat transfer approaches, including conduction, convection, and radiation, to transfer mainly the joule heating generated in the core conductor to ambient with a low pressure of 18.8 kPa, which is the air pressure at cruising height of wide-body aircraft (12.2 km), are considered and modeled. To compare the proposed cables to the designs based on IEC 60502 and AS50881, ${J}$ is introduced, which is the product of cables’ overall mass in a unit length and diameter. The results show that besides benefiting multilayer, multifunction insulation systems to resolve aircraft cables’ challenges, the overall diameter and weight of the designed cables are lower than single-layer insulation system designs based on AS50881 and IEC60502.

All-electric aircraft (AEA) emergence is considered a promising initiative toward achieving net-zero aviation. Future wide-body AEA will require electric power systems (EPS) with high power density and minimal system mass. Power cables, a crucial element of the aircraft EPS, need to be designed to enhance the EPS's overall power density. At the cruising altitudes of wide-body AEA, the limited heat transfer by convection poses significant thermal challenges for the design of power cables. The challenges are further intensified when employing bipolar medium voltage direct current (MVDC) EPSs, typically consisting of two power cables, negative and positive poles, positioned adjacent. The cable's surface area influences both radiative and convective heat transfers. This book chapter deals with the design, fabrication, and testing of aircraft MVDC power cables. Multilayer multifunctional electrical insulation (MMEI) systems were recently introduced instead of single-layer insulation in the aforementioned cables, which are discussed. In addition to delineating coupled electrical, thermal, and computational fluid dynamic models to obtain thermal distribution and electric stress within the cable and using the model for optimal design of cable and duct geometries, all modeling details in COMSOL Multiphysics are also explained, resulting in this chapter book as a textbook and valuable reference.

… The temperature changes of the insulation layer and the core of the copper wire … core temperature, the insulation layer needed to be stripped beforehand. Using the midpoint of the wire …

… In this paper, the error analysis for the conventional three-core cable thermal rating … core cable under three-phase unequal load, an improved thermal rating method for three-core cables …

For wide-body all-electric aircraft (AEA), a high-power-delivery, low-system-mass electric power system (EPS) necessitates advanced cable technologies. Increasing voltage levels enhances power density yet poses challenges in aircraft cable design, including managing arc-related risks, partial discharges (PDs), and thermal management. Developing multilayer multifunctional electrical insulation (MMEI) systems for aircraft applications is a feasible option to tackle these challenges and reduce the size and mass of cable systems. This approach involves selecting layers of different materials to address specific challenges. Our prior research concentrated on the modeling and simulation-based design of MMEI systems for MVDC power cables. Experimental tests are essential for determining the behavior of PDs under varying pressure conditions. Also, the dielectric strength and time to failure of the designs need to be assessed. In this work, the fabrication process of a down-selected MMEI flat configuration is discussed and analyzed. This paper analyzes the fabrication process of power cables employing MMEI configurations and evaluates the PD characteristics of down-selected ARC-SC-T-MMEI cable samples. This study presents a detailed analysis of the characteristics of PD under atmospheric and low-pressure conditions, which will provide essential insights into the design of MVDC cables for future AEA applications.

… generates heat, which is released into the environment through the cable's metallic layers and insulation. In the presence of a temperature gradient, heat is an energy form that is …

The design of lightweight, high-power medium-voltage direct current (MVdc) cables is crucial for future all-electric aircraft (AEA) to ensure reliable performance and durability under harsh environmental conditions. These cables must effectively mitigate partial discharge (PD) and insulation degradation to support the high-power demands of next-generation aviation. In our previous work, we developed multilayer multifunctional electrical insulation (MMEI) systems to tackle these challenges. This article presents the detailed experimental studies conducted on these MMEI structures, both as flat samples and cable prototypes. Among all the designed MMEI structures, previously designed ARC-SC-T-MMEI was selected for PD study due to its multifunctionality. First, the flat sample for the selected MMEI design is fabricated, and the fabrication process is optimized by analyzing the PD characteristics observed under different fabrication conditions. Building upon these findings, a cable prototype is created using the optimized MMEI samples. Subsequently, the PD behavior of the optimized fabricated samples is investigated under varying pressure levels to replicate the actual conditions encountered in an aircraft environment. The PD behavior of this cable prototype is rigorously studied and analyzed using the Pearson correlation coefficient to assess its performance and reliability in operational conditions. Furthermore, the dielectric strength of these samples is examined under dc voltage. A two-parameter Weibull distribution is used to analyze the effect of pressure on the breakdown of the fabricated samples. This article provides detailed insights into the fabrication and performance analysis of MMEI systems under dc voltage at atmospheric and low pressures.

… of copper-core cable with mica insulation (HC0) and aluminum-core cable with PI insulation … oxidation rate and easier outflow of liquid aluminum through cracks at low pressure. HA0 …

Electrical fires perennially rank first in fire occurrence types, with conductor overcurrent being one of the main inducements. This topic draws significant attention from scientific researchers and fire investigators. To understand the overcurrent fault and combustion characteristics of copper‐clad aluminum conductors, this paper examines 2.5 mm2 copper‐clad aluminum conductors that meet national standards, investigating morphological changes, temperature variations in the core and insulation layer, and flame propagation patterns under overcurrent conditions. Experiments using an electrical fault simulation device were conducted to study overcurrent failures of copper‐clad aluminum conductors under 52.5–105 A conditions. The results indicate that when the current exceeds 67.5 A, the conductor undergoes a series of changes during energization, including smoking, expanding, carbonizing, burning, and breaking; at 52.5 A, the insulation layer reaches thermal equilibrium at 150 s without combustion; for currents between 60–67.5 A, wire core temperature variations can be divided into three stages; at 75 A, the insulation layer reaches thermal equilibrium 10s before breaking; currents above 82.5 A see a sharp increase in temperature in both the core and insulation layer before the conductor breaks; above 97.5 A, the conductor first breaks and then burns. The research results have significant theoretical value in improving the scientific rigor of fire accident investigations and forensic evidence examinations.

With the technological development of the insulation materials used in underground cable lines, they undergo a significant improvement in their operational performance. The high costs associated with the production and operation of the oil-filled cables and on the other hand having the new advanced technologies of the dry insulation materials create suitable prerequisites for the wide penetration of the cables with advanced insulation. Today, high voltage cables can be produced with insulation material of Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Ethylene Propylene Rubber (EPR), High Ethylene Propylene Rubber (HERP) and Cross Linked Polyethylene (XLPE). The construction of contemporary high-voltage cable -comprises: a conductor, a semi-conductive shield of the conductor, insulation, a semi-conductive shield of the insulation, a metal sheath or shield (or a combination of both), a water-blocking layer, a cable armor and an outer sheath. The article discusses the layers forming the cables structure, as well as their functions for ensuring the reliable electrical operation. The main parameters of each cable layer are described.

Electrical cable insulation, mainly composed of polymeric materials, progressively deteriorates under thermal, electrical, mechanical, and environmental stress factors. This degradation reduces dielectric strength, thermal stability, and mechanical integrity, thereby increasing susceptibility to failure modes such as partial discharges, arcing, and surface tracking—recognized precursors of fire ignition. This review consolidates current knowledge on the degradation pathways of cable insulation and their direct link to fire hazards. Emphasis is placed on mechanisms including thermal-oxidative aging, electrical treeing, surface tracking, and thermal conductivity decline, as well as the complex interactions introduced by flame-retardant additives. A bibliometric analysis of 217 publications reveals strong clustering around material degradation phenomena, while underlining underexplored areas such as ignition mechanisms, diagnostic monitoring, and system-level fire modeling. Comparative experimental findings further demonstrate how insulation aging modifies ignition thresholds, heat release rates, and smoke toxicity. By integrating perspectives from materials science, electrical engineering, and fire dynamics, this review establishes the nexus between aging mechanisms and fire hazards.

The transition to a more sustainable energy infrastructure necessitates innovations in cable materials and recycling technologies. Traditional materials like crosslinked polyethylene have limitations in recyclability and thermal resistance, prompting research into advanced polyolefin blends and copolymers. These novel materials offer improved electrical and thermal properties but present challenges in polymer compatibility and processing. Recycling cable plastics is further complicated by material heterogeneity, contamination, and the presence of thermoset components. Recent advances in mechanical and chemical separation techniques have improved the recovery and reuse of polymer fractions. Rejuvenation technologies, such as silicone injections, offer additional pathways to extend cable life and reduce waste. However, contamination from conductive particles like carbon black remains a critical barrier to reusing recycled materials for high-voltage insulation. This paper reviews current trends and solutions in cable technology, focusing on recyclability, material compatibility, and infrastructure refurbishment.

Reliable DC cable insulation is crucial for photovoltaic (PV) systems and high-voltage DC (HVDC) networks. However, conventional materials such as cross-linked polyethylene (XLPE) and polyvinyl chloride (PVC) face challenges under prolonged DC stress—notably space charge buildup, dielectric losses, and thermal aging. Cross-linked polyolefin (XLPO) has emerged as a halogen-free, thermally stable alternative, but its comparative DC performance remains underreported. Methods: We evaluated the insulations of virgin XLPO, XLPE, and PVC PV cables under ±1 kV DC using time-domain indices (IR, DAR, PI, Loss Index), supported by MATLAB and FTIR. Multi-layer cable geometries were modeled in MATLAB to simulate radial electric field distribution, and Fourier-transform infrared (FTIR) spectroscopy was employed to reveal polymer chemistry and functional groups. Results: XLPO exhibited an IR on the order of 108–109 Ω, and XLPE (IR ~ 108 Ω) and PVC (IR ~ 107 Ω, LI ≥ 1) at 60 s, with favorable polarization indices under both polarities. Notably, they showed high insulation resistance and low-to-moderate loss indices (≈1.3–1.5) under both polarities, indicating controlled relaxation with limited conduction contribution. XLPE showed good initial insulation resistance but revealed polarity-dependent relaxation and higher loss (especially under positive bias) due to trap-forming cross-linking byproducts. PVC had the lowest resistance (GΩ-range) and near-unit DAR/PI, dominated by leakage conduction and dielectric losses. Simulations confirmed a uniform electric field in XLPO insulation with no polarity asymmetry, while FTIR spectra linked XLPO’s low polarity and PVC’s chlorine content to their electrical behavior. Conclusions: XLPO outperforms XLPE and PVC in resisting DC leakage, charge trapping, and thermal stress, underscoring its suitability for long-term PV and HVDC applications. This study provides a comprehensive structure–property understanding to guide the selection of advanced, polarity-resilient cable insulation materials.

In most underground power cables, cross‐linked polyethylene (XLPE) is utilized as the main insulating material, while polyvinyl chloride (PVC) is usually used as a nonmetallic sheath or jacketing for the cable. Accordingly, improving the electrical and thermal characteristics of these materials leads to an increase in cable dielectric strength, besides a rise in the current capacity of the underground power cables. Thus, enhancing the thermal characteristics of cable insulation is the goal of many research studies. In this regard, increasing the current capacity of underground power cables is an essential topic for electrical distribution and transmission networks. This usually occurs by increasing the cross‐sectional area of the cable conductor, which means raising the cost of transmitting electrical energy. Another proposed alternative may be to improve the thermal properties of the dielectric material using nanotechnology to allow better dissipation of heat resulting from the cable losses. This article proposes the use of nano‐composite dielectrics to increase the current capacities of underground power cables. Nano‐fillers are used to enhance the thermal and electrical characteristics of XLPE and PVC, which represent cable dielectric materials. Accordingly, in this paper, many experiments are conducted on various nano‐dielectric materials to choose the most appropriate nano‐dielectrics for improving both the thermal and electrical properties. Hence, measurements are performed on the thermal and electrical properties of dielectric nano‐materials manufactured in the laboratory. Further, calculations of the cable's current capacities by the use of the measured properties of nano‐dielectrics are done considering several backfill soils. From the obtained measurements and calculations carried out on cable capacities, it is concluded that the use of XLPE/ZnO 5 wt.% as the insulation and PVC/ZnO 5 wt.% as the jacket material increased the cable current capacity by 6.2% for a cable of 33 kV rating, 9.2% for 66 kV cable, and 15.7% for 220 kV cable when wet clay is used as backfill soil. From the calculations carried out it is found that the use of nano‐composite dielectrics reduces the temperature of the cable components by significant values. For example, the core temperature of the 33 kV cable is reduced by 15.6°C, while for the 66 kV cable, the cable core temperature is decreased by 12.6°C, and for 220 kV the conductor temperature is reduced from 71.3°C to 58.3°C when each cable is loaded by its rating.

This article presents a review of the aging mechanisms and lifetime estimation methodologies for medium and high-voltage cross-linked polyethylene (XLPE) cables under harsh environmental service conditions, which are integral to the reliability and safety of modern electrical power systems. This article first briefly delves into the various aging mechanisms experienced by power cables, describing the physical and chemical processes that underlie the degradation of XLPE cable insulation over time. The discussion then extends to various life models: physical life models that describe material property changes under operational stresses, phenomenological life models and multistress models that consider the concurrent impact of multiple stressors on cable aging, and probabilistic and reliability lifetime models, which introduce a statistical perspective to the remaining lifetime estimation, essential for risk assessment in power systems. The review also explores frequency-based life models that investigate the effects of operational frequencies on cable longevity. A significant focus is placed on enlargement laws and electrical treeing life models, shedding light on specific degradation phenomena pertinent to high-voltage insulation. This article next examines artificial intelligence–based life models, a cutting-edge approach that integrates traditional knowledge with advanced computational techniques, such as machine learning and data analytics, for enhanced prediction of cable life expectancy. Future research directions are also proposed in this article, which proposes a finite element method-AI Assisted partial discharge analysis and remaining useful lifetime estimation model for XLPE cables. This comprehensive review aims to serve as an indispensable resource for engineers and researchers, offering a holistic understanding of the state-of-the-art and future directions in the domain of cable life estimation and prognostics.

This study presents estimation of the remaining lifespan of a low-voltage electric cable commonly used in building installations. The cable under investigation is a $\mathbf{1. 5} \mathbf{~ m m}^{\mathbf{2}} \mathbf{4}$-core steel wire armored cable, with cross-linked polyethylene (XLPE) as the primary insulation, and polyvinyl chloride (PVC) used for the bedding and outer jacket. To evaluate the long-term performance of the cable and predict its operational lifespan, accelerated life testing was conducted under controlled thermal stress conditions. The accelerated aging data was then used to develop a life estimation model based on the Arrhenius equation, providing a practical tool to predict the remaining service life of the cable. This approach helps assess the insulation's long-term reliability and supports proactive maintenance strategies to prevent unexpected failures in building electrical networks.

This chapter provides a comprehensive overview of the historical evolution and key technological milestones of insulating plastics, covering traditional materials such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and cross-linked polyethylene (XLPE), as well as sustainable and smart next-generation novel materials. It summarizes the development and challenges of traditional insulating plastics, including key issues such as environmental impact, operational reliability, and service life, while highlighting how the introduction of functional fillers, molecular structure design, and the reconstruction of polymer network structures can drive the transformation of insulating plastics toward high-performance, green, and smart applications. By integrating the latest advancements in materials science, green chemistry, and electrical engineering, this chapter reveals how insulating plastics can be redesigned to meet modern demands for performance, functionality, and sustainability, providing theoretical support and technical references for the future development of eco-friendly and smart electrical insulating materials.

International audience

… enables continuous operation of PV installations, whereas cables with a lifetime less … cable types using the combined-accelerated stress testing (C-AST) protocol. Representative cables …

Cables are critical to the safe and reliable operation of nuclear power plants (NPPs) since they are widely used as a connection medium for various safety-critical equipment. According to research data and operational experience (OPEX), cable materials can degrade with time, resulting in reduced dielectric strength and higher leakage current. Cables may degrade gradually over time under normal service conditions and fail unexpectedly as a result of sudden exposure to harsher environments, such as Secondary Steam Line Breaks (SSLBs), or when required to operate under the severe conditions of a design basis event, such as a Loss-of-Coolant Accident (LOCA). To assess the condition of medium- and low-voltage cables in Canadian nuclear power plants, numerous inspection methods and electrical testing techniques are employed. These techniques include dielectric spectroscopy, polarization/depolarization current analysis, reflectometry, dielectric standby tests, AC partial discharge, and very-low-frequency (VLF) Tan Delta assessments for medium-voltage (MV) cables. While these methods provide precise diagnostic insights, they require cables to be disconnected at both ends and de-energized, posing operational constraints. Consequently, on-line plant cable monitoring has garnered significant interest, particularly for new reactor developments and large-scale NPP refurbishments. This paper provides a comprehensive benchmarking of existing technologies and a state-of-the-art review of modern cable assessment methodologies. It examines commercially available solutions and ongoing research in power testing for low-voltage (LV) and MV cables, with a particular focus on their applicability in nuclear power settings.

… For example, XLPE cables may be operated continu ously at … in cable jacketing is the jacket materials in building wire, fiber … over a metal conductor or a core wire by passing it through a …

The distribution grid comprises cables with diverse constructions. The insulating material used in low-voltage (LV) distribution cables is predominantly PVC. Furthermore, the presence of cables with different structures in the grid poses challenges in detecting the aging of the cable network. Finding a universal and dependable condition-monitoring technique that can be applied to various types of cables is indeed a challenge. The diverse construction and materials used in different cables make it difficult to identify a single monitoring approach that can effectively assess the condition of all cables. To address this issue, this study aims to compare the thermal aging behavior of different LV distribution cables with various structures, i.e., one cable contains a PVC belting layer, while the other contains filler material. The growing adoption of distributed generation sources, electric vehicles, and new consumer appliances in low-voltage distribution grids can lead to short, repetitive overloads on the low-voltage cable network. Hence, these cable samples were exposed to short-term cyclic accelerated aging in the climate chamber at 110 °C. The cable’s overall behavior under thermal stress was evaluated through frequency and time domain electrical measurements (including tan δ and extended voltage response) and a mechanical measurement (Shore D). The tan δ was measured in the frequency range of 20 Hz–500 kHz by using the Wayne-Kerr impedance analyzer. The extended voltage response measurement was conducted using a C# application developed in-house specifically for laboratory measurements in the .NET environment. The study observed a strong correlation between the different measurement methods used, indicating that electrical methods have the potential to be adopted as a non-destructive condition-monitoring technique.

The rapid growth of electrical energy demands raises the need for the modernization of distribution grids. Medium-voltage (MV) aged cables are infrastructures facing significant challenges that can compromise the security of supply and reduce the reliability of power grids. To address the challenges, there is a growing interest in optimizing cable replacement and management strategies. This comprehensive review focuses on the technical challenges and innovations associated with MV cable replacement, highlighting defect detection, lifetime estimation, reliability assessment, and management strategies. Various methods for detecting and monitoring cable defects and discussing their advantages and limitations are surveyed. Moreover, different models and techniques for estimating the remaining useful life of MV cables are explored, emphasizing the importance of accurate predictions for assessing cable reliability and optimizing replacement schedules. Furthermore, emerging technologies that enhance cable management strategies are also highlighted. This review provides insights and recommendations for future research and development, paving the way for the sustainable evolution of power grids.

… and actively demonstrates our core values of inclusive … earth conductor, and (6) a PVC ground outer sheath. Figure 3 … shows the stress control tube, and 7 labels the cable jacket. …

The increasing penetration of distributed generation sources in low-voltage distribution grids, electric vehicles, and new appliances from the consumer side can generate short repetitive overloads on the low-voltage cable network. This work investigates the change in the dielectric properties of low-voltage cable insulation caused by short-term overloads, examining how the cable structure affects the dielectric characteristics of the cable specimens in the case of cyclic short-term thermal aging. PVC-insulated low-voltage cable samples were exposed to an accelerated aging test in a temperature-controlled oven after changing their structures by removing different layers. Three aging cycles, each of six hours, were applied to the samples. After each cycle, the tan δ and capacitance were measured by an Omicron DIRANA Dielectric Response Analyzer in the laboratory at room temperature 24 ± 0.5 °C. Furthermore, the polarization and depolarization currents were also studied. The results show that changing the cable structure impacts the dielectric parameters; in particular, the effect of the belting layer is significant. From the point of view of aging, the PVC belting layer protects the diffusion of the plasticizers of the inner structure. The findings of the study show that an asymmetric aging phenomenon can be observed in different polymeric components of the cables, even though the cables were aged in an air-circulated oven ensuring a homogeneous temperature distribution in the samples.

This chapter provides a systematic review of the evolution of electrical insulating materials, covering solid, liquid, and gas types. From early natural materials such as paper, rubber, mineral oil, and air to synthetic polymers and high-performance materials in the 20th century including phenolic resins, epoxy resins, cross-linked polyethylene, and sulfur hexafluoride, insulating materials have achieved major advances in dielectric strength, thermal stability, and reliability. Today, insulation systems face new challenges such as aging, degradation, pollution, recyclability, and performance limits. In response, sustainable and smart materials have emerged, including biodegradable liquids, eco-friendly gases, recyclable solids, and smart insulators. The evolution of insulating materials reflects a transition from functionality toward environmental responsibility, providing critical support for sustainable power infrastructure.

This paper presents a transmission-line model of a multiple-shields multiconductor cable. This unified model includes at the same time the propagation and cross-coupling characteristics of the electrical wires and of the cable-shields. It also includes the electromagnetic characteristics of the shields (in terms of transfer impedance and transfer admittance). It is derived in compliance with the multiconductor-transmission-line theory and it is valid whatever the connection configurations at the shield ends are. Therefore, it makes it possible the modelling of realistic connection problems ranging from ideal 360° shield connections to simple bonding wires. In addition, it is suitable for both electromagnetic susceptibility and emission problems. The paper proposes a physical explanation of the derived per-unit-length matrices. This unified model is also used to define the required conditions for being able to calculate the response of a shielded-cable in a two-steps model in which the shield problem and the inner shield problem are solved in sequence. Finally, the paper illustrates an application of the model in order to evaluate performances of a shielded-cable-link on crosstalk configurations with respect to various electrical bonding techniques of the shield.

This article presents the coupling characteristics of shielded multiconductor cables under high-altitude electromagnetic pulse (HEMP) numerically and experimentally. The numerical analysis is employed to study the coupling characteristics of a representative shielded multiconductor cable under different conditions first. The impacts of cable wiring configurations, cable parameters, and propagation direction of incident electromagnetic waves are given. Then, a horizontally polarized hybrid EMP simulator is constructed, and some radiated tests are conducted to validate the conclusions obtained in numerical analysis. The results show that the open circuit of the shielding layer results in the core wire coupling to the same high voltage as the shielding layer, while grounding the shielding layer significantly reduces the coupling voltage on core wires. In addition, increasing cable height, cable length, elevation angle, and azimuth angle all result in an amplification of the level of coupled current. The experimental outcomes of the radiated tests validate the effectiveness of the simulation and the precision of the numerical analysis results.

The shield multiconductor cable has been widely utilized in smart power grid with the characteristics of compact structure, low loss, high current carrying capacity and less environmental pollution. To achieve the accurate estimation of shield multiconductor cable for electromagnetic application, the partial element equivalent circuit (PEEC) topology with high-frequency parasitic parameters is established, and the distributed parameter model with Γ topology is proposed to describe the dynamic transmission features. The skin and proximity effect of shield cable can affect current distribution density, and the trivial solution with insufficient model estimation accuracy will result in the fitting residuals. Thus the R-L ladder based on N-branch topology is analyzed, and the vector fitting iteration strategy achieves the accurate approximation and fast convergence for the estimation model. Considering the continual charging and discharging characteristics caused by high-frequency dv/dt and di/dt, Neumann Law and Mirror theory are employed to derive the partial capacitance of shield multiconductor cable model. Finally, the simulation and test results with the presented cable model for conducted EMI assessment are performed on the test bench, the reliability of the parameter estimation is experimentally verified and its effect on high-frequency conducted interference is accurately characterized.

Multi-conductor cable is the key factor that causes voltage reflection and electromagnetic interference (EMI) in motor drive system. In order to accurately predict the EMI noise of motor drive system, it is necessary to establish an accurate multi-conductor cable model. However, the measuring port of impedance analyzer is too narrow to accurately measure the impedance parameters of long straight cable. In this paper, it is proved by theory and simulation that the impedance of the unit length circular cable can be equivalent to that of the unit length long straight cable when the radius of circular cable is greater than 0.25 m. The long straight cable is bent into the circular cable to measure the impedance parameters, and the multiconductor cable coupling model with shielding is established. Compared with the Q3D model, the simulation results of the multi-conductor cable coupling model are closer to the experimental results.

… because the lightning electromagnetic impulse releases high-power ultra-wideband electromagnetic energy in the electromagnetic environment, which will couple to the cables in the …

With the developments in power electronics equipment, the electromagnetic environment has become severe for electronic equipment. In the smart facility field, the stable operation of electronic devices is indispensable, and noise countermeasures must be improved. To suppress intrusive noise from cables, shielded cables are used in many cases. However, electromagnetic induction cannot be suppressed when the shield is grounded at one end, and when grounding both ends of the shield, current flows through the shield creating intrusive noise in the cable. That is, even if a shielded cable is used, a sufficient effect cannot be obtained. Therefore, as a countermeasure, this study prototypes and evaluates cables that combine double shielded cables with magnetic cores. Evaluations conducted using the copper pipe method, triaxial method, and impulse test confirm that the shielded performance improved by 10–30 dB compared with the conventional shielded cable.

The prediction of voltage stresses in transformer and machine windings requires the ability to calculate pulse propagation effects on the feeding cable with sufficient accuracy. The use of commonly available cable models in electromagnetic transient (EMT) programs can lead to voltage wave fronts with too weak damping at very high frequencies. This work shows a method for improving the accuracy of such models by usage of measured coaxial mode propagation characteristics. The information is introduced into a wide-band multi-conductor cable model at high frequencies by a merging procedure, with only a minor impact on the non-coaxial modes of propagation. The application of the developed model is demonstrated for cases where the metallic sheaths are grounded at one end only, or are cross-bonded.

Efficient modelling of both skin and proximity effects in solid and hollow cylindrical conductors over an ultrawide frequency range is performed. The transition factors (TFs), denoted by TFs, responsible for the transition property between low and high frequency regions are at first extracted using an efficient analytical technique. Then, they are applied for the development of fields within and around the conductors, respectively, leading to the definition of the other new compound TF. Therefore, the skin and proximity effects with the transition property along a wide frequency range are accurately predicted, and enclosed with compact elegant formulas. Also, it is shown that the lossy conductors cannot be always considered as equipotential surfaces during the potential derivation because they can behave as transparent surfaces to the magnetic field lines, and this concept can be explained by using the TFs properties. Moreover, the transfer impedances of a shielded multiconductor cable with hollow shields are also generalized with TFs and the skin and proximity effects included, together with the transfer impedances examined. The induced common- and differential-mode within shield multiconductor cables, due to the coupling through their hollow shield, are fast predicted accurately using the developed transition property. Finally, the proposed model is validated in comparison with both COMSOL Multiphysics and HFSS software.

… wire and a shielded cable, spanning a total length of 1 m3. The single wire has an inner radius of 0.7 mm and an insulation … shielded cable's core conductor to evaluate electromagnetic …

A comprehensive formulation for analyzing subsea cables in the frequency domain is introduced. This cable design encompasses multiple conductors, necessitating the resolution of a complex, coupled wave equation. To ensure accuracy and reliability, the derived results were rigorously validated against simulations conducted using PSCAD software.

A new method is proposed for the generalized distributed capacitance matrix extraction of multi-conductor transmission lines (MTLs) composed of insulated cables based on S-parameter measurements in this paper. The theoretical derivation of the proposed method is presented. Then, a simulation model is established, and the distributed capacitance matrix of the model is extracted according to the proposed method. The terminal responses of the MTLs are calculated according to the distributed parameters extracted through the S-parameter measurements and calculated based on the analytical formula. The calculated results are compared with the simulation results. The simulation results demonstrate that the proposed method can accurately extract the distributed capacitance matrix of the MTLs. The results also indicate that significant errors are introduced when the analytical formula under wide separation approximation is used to calculate the distributed capacitance matrix of MTLs composed of insulated cables. In contrast, the proposed method is accurate. The proposed method is believed to have strong potential for applications in electromagnetic radiation analysis and fieldline coupling of MTLs composed of insulated cables.

The reliable and efficient computational approach for the cable interference in gas insulated substations (GIS) is presented. The hybrid domain decomposition method-multilevel fast multi-pole algorithm (DDM-MLFMA) is presented herein. This technique determines the specifications of GIS cables for RG58 and AWG23. Self and mutual interference are identified utilizing the very fast transient overvoltage (VFTO) transient interference signal. The hybrid technique offers a numerical simulation to replicate the impact of the VFTO interference signal. Utilizing the matrix-vector multiplication product (MVX) to address compression and approximation challenges, the hybrid approach proves reliable and pragmatic. Because of its computational nature and explicit factorization reduction, this strategy reduces computation time and memory requirements. Consequently, the system's complexity follows a linear trend under this proposed approach. The computed results are juxtaposed with traditional methodologies to validate the effectiveness of the proposed algorithm.

… led to a greater utilization of multi-conductor stranded cables. Calculating the electrical … on electromagnetic shielding performance is investigated. There are two different kinds of cables …

When the electromagnetic radiation emitted by the lightning channel couples to the shields of overhead or buried cables, it induces large currents causing transient overvoltages between the internal conductors and the shield. These disturbances can alter the insulation of the cable and also cause malfunctions in the electrical devices connected to it. For the analysis by simulation of the electromagnetic coupling between a buried shielded single core cable and a lightning channel, this paper presents a modeling developed from the extended transmission line theory and the topological electromagnetic formalism. It also discusses the role of a bare shield wire buried parallel to the shielded Single Core cable (SC cable) to reduce these disturbances. We validate the modeling used by comparing our calculation results with those achieved by measurement and we propose some applications to highlight the role of the shielding wire in reducing the disturbances induced in the shielded SC cable.

To address the limitations of low detection efficiency and poor spatial resolution of traditional cable insulation diagnosis methods, a novel cable insulation diagnosis method based on impedance spectroscopy has been proposed. An impedance spectroscopy analysis model of the frequency response of high-voltage single-core cables under different aging conditions has been established. The initial classification of insulation condition is achieved based on the impedance phase deviation between the test cable and the reference cable. Under localized aging conditions, the impedance phase spectroscopy is more than twice as sensitive to dielectric changes as the amplitude spectroscopy. Leveraging this advantage, a multi-parameter diagnostic framework is developed that integrates key spectral features such as the first phase angle zero-crossing frequency, initial phase, and resonance peak amplitude. The proposed method enables quantitative estimation of aging severity, spatial extent, and location. This technique offers a non-invasive, high-resolution solution for advanced cable health diagnostics and provides a foundation for practical deployment of power system asset management.

… XLPE insulations with thermoplastic ones in high-voltage DC cables. The main reason for … within the insulation layer different from HVAC cables. Thermoplastic cable insulation is …

Medium voltage high-frequency transformer (MVHFT), the key component in a MV solid-state transformer (MVSST), requires high reliability on its insulation parts. With the increase of power density, the insulation design of the MVHFT becomes a big challenge. The transformer needs to ensure both high breakdown (BD) strength for short-term fault tolerance and low partial discharge (PD) for long-term reliable operation. Therefore, beginning with the electric stress analysis and the anti-corona consideration, a mass-manufacturable insulation structure is proposed in this article. In the structure, an improved multishielding structure with an optimized shield potential design is used to reshape the electric field (E-field) distribution for higher BD strength and lower PD. And an end-winding stress grading (SG) method is proposed and modeled for both the structure and the material used. Finally, with the proposed insulation structure, a 100 kW PD free transformer prototype with 75 kV base insulation level (BIL) is built. It passed all insulation tests. Also, the prototype realizes high power density under a high insulation level, which reaches 11.2 kW/L.

… advantageous thermal and electrical properties. In order for the PP to be used as an insulating materials for HV power cable, however, it is necessary that not only the high modulus (…

Health assessments of high-voltage power cables are important for stable operations of power grids; however, most current health assessment model parameters lack whole cable test data, making them unable to effectively characterize the insulation aging state of whole cables. In this paper, a dielectric loss measurement device for high-voltage cables is developed. Using a high-voltage amplifier and high-precision dielectric loss measurement algorithm, the dielectric loss values of whole cables at different aging stages are measured, and the physicochemical and electrical characteristics of XLPE slice samples at each aging stage are analyzed. Through the analysis of high-voltage dielectric loss, crystallinity, carbonyl index, AC breakdown field strength, and elongation at break, aging correlation parameters are determined. The characteristic high voltage frequency domain dielectric response and delamination degree are proposed to characterize the aging state of cable insulation. The correlation between the high voltage frequency domain dielectric characteristics and cable insulation aging state is established. Finally, an assessment method of the insulation aging state of high-voltage cable is developed, providing a reference for the diagnosis and assessment of the insulation state of high-voltage XLPE cable on site.

… -cycle voltage disturbances caused by the incipient fault are obtained by performing an applying voltage test on a 10 kV cable with local insulation defects. Then, for the voltage signal …

This review focuses on the use of polyolefins in high‐voltage direct‐current (HVDC) cables and capacitors. A short description of the latest evolution and current use of HVDC cables and capacitors is first provided, followed by the basics of electric insulation and capacitor functions. Methods to determine dielectric properties are described, including charge transport, space charges, resistivity, dielectric loss, and breakdown strength. The semicrystalline structure of polyethylene and isotactic polypropylene is described, and the way it relates to the dielectric properties is discussed. A significant part of the review is devoted to describing the state of art of the modeling and prediction of electric or dielectric properties of polyolefins with consideration of both atomistic and continuum approaches. Furthermore, the effects of the purity of the materials and the presence of nanoparticles are presented, and the review ends with the sustainability aspects of these materials. In summary, the effective use of modeling in combination with experimental work is described as an important route toward understanding and designing the next generations of materials for electrical insulation in high‐voltage transmission.

The intermediate joint of high-voltage cables, as a critical component in the power transmission system, plays a direct role in the stable operation of the entire electrical system. In recent years, frequent explosions of intermediate joints in high-voltage cables have led to significant economic losses and safety risks. Therefore, studying the explosion mechanisms and explosion prevention measures of high-voltage cable intermediate joints is particularly important. This article provides a systematic review of the explosion mechanisms and explosion prevention measures for high-voltage cable intermediate joints. It begins by introducing the composition of cable systems and the structural features of the 220 kV prefabricated cable joint. Next, the article elaborates on the spatiotemporal evolution process of cable joint explosions. Typically, a cable joint explosion undergoes several stages: partial discharge, arc breakdown, and insulation material decomposition, which ultimately leads to explosion and ignition. Subsequently, the article reviews each of these dynamic stages in detail. Finally, the article discusses the existing explosion prevention measures and their shortcomings, and proposes future directions for the development of explosion prevention measures. This article can provide a theoretical foundation and technical reference for the research on the explosion mechanisms of high-voltage cable joints, as well as for the development of explosion prevention measures.

This paper proposes a new prognostic method capable of preventing catastrophic failures in Medium Voltage (MV) power cables. The main objective is the development of a monitoring system focused on the detection and localization of cable overtemperatures in underground distribution networks. The predictive analysis proposed here is based on a Multi-Layer neural network with Multi-Valued Neurons (MLMVN), which elaborates measurements of high frequency signals transmitted through Power Line Communication (PLC) devices. Therefore, the prognostic method does not require the introduction of additional components since the power line is already equipped with a communication system. This allows low intrusion and the possibility of monitoring power lines during their operation. Furthermore, the MLMVN-based classifier processes magnitude and phase of the received signals without preliminary coding steps and ensures a low computational cost. The main theoretical concept on which the predictive analysis is based is the detection of malfunctions starting from their effects on the cable parameters. For this reason, an RG7H1M1 cable has been experimentally characterized in the frequency range between 90 kHz and 1 MHz, both in nominal conditions and in overheating situations generated by means of a climatic chamber. The changes in the electrical parameters of the cable modify the transmitted signal and the monitoring system proposed here allows the identification and localization of the overheated section with high accuracy.

… insulation recovery time of the damp cable joint’s interface is shorter than the action value of relay protection, resulting in the line … of 20 kV damp three-core cable joint was investigated. …

This article presents the recent developments in the field of evaluation of the breakdown performance and remaining lifetime of XLPE insulation and analyzes the accuracy of existing lifetime prediction models through experiments. The effects of the crystalline morphology, cable thickness and sampling location of XLPE insulation on the evaluation of short-term breakdown performance are reviewed in the context of the experiments. The study reviews the application of the Ramu, Simoni, and Ramu multi-stress lifetime prediction models and explores the other remaining lifetime prediction models under the combined electrothermal stresses which are applicable to XLPE insulation. Finally, this paper recommends the most effective engineering evaluation methods and provides suggestions for improving the electrical performance of XLPE insulation for high-voltage cables.

incredibly crucial pieces of gear for tall-voltage, big-capacity, and distant communication power transfer are strong-voltage electrical currently (HVDC) & hot-voltage alternating electricity (HVAC) lines. Electrical trees represents the primary issue endangering the security and sustainable functioning with HVDC other HVAC cabling lines. It constitutes a this was before the-breakdown event that causes insulation components to degrade. The accomplishments in teh paper of electricity trees with HVDC then HVAC wires are compiled and analyzed within this publication. To completely comprehend the electromagnetic deterioration process in insulating materials, the beginning principles that comprise the electromagnetic tree, encompassing Kepler electrical current-mechanical stress, charging infusion-extraction, charge capturing, and electricity hypotheses, are expanded. The effects from a strong current, a hot environment, and physical strain upon a power tree are then discussed. The link involving charge transfer until the power trees is analyzed and displayed while tendencies are outlined. By adding mineral and natural compounds to insulating substances, the cancellation techniques associated with the electromagnetic trees are proposed. These suppression processes are provided through a perspective of its framework-property and initial model-macroscale correlations. The tall-precision initiating theories, tall-dependence of many physiological industries, and strong-efficiency suppression approaches have recently been the primary focus among electric trees research projects. While there is another operational problem with determining the viability during their owners. use of them with HVDC along with HVAC wiring, the results offer scientific backing to boost the electrically efficiency of materials used as insulation.

This study investigates the effect of operating temperature on the breakdown strength and aging life parameter of cross-linked polyethylene (XLPE) insulation for 500 kV extra-high voltage alternating current (EHVAC) cables. The test samples were cut from a properly degassed real 500 kV XLPE cable. The continuous-rising voltage breakdown tests and step-up voltage breakdown tests were conducted at 30 °C, 50 °C, 70 °C, and 90 °C, respectively. The results show that, the AC breakdown strength decreases with increasing operating temperature regardless of the thickness of XLPE samples. When the temperature is 70 °C or below, increasing the thickness of samples effectively slows down the decreasing trend of the breakdown strength. However, at 90 °C, increasing the sample thickness cannot resist the decrease in AC breakdown strength. By analyzing the aging life curves of the XLPE samples at different temperatures, it is found that the aging life parameters of the XLPE samples at 30 °C and 90 °C are 18 and 14, respectively. It is perceived from testing results that even after continuous operation for 40 years, the tested XLPE material can possess AC breakdown strengths of 44.6 MV/m and 28.3 MV/m at 30 °C and 90°C, respectively. This study provides a reference basis for the design of insulation thickness and the electrical life assessment of 500 kV EHVAC cables during the long-term operation.

This article updates previous reviews of life and reliability models for high-voltage direct-current (HVDC) cables. The update is motivated by the impressive research and development activities on HVDC cable systems in the last years, with many projects at increasing levels of voltage and power; this makes the sound evaluation of the life and reliability of HVDC cables crucial. Physical and phenomenological life models proposed over the years for constant electrical and thermal stresses are reviewed first, including the relevant probabilistic framework and the effects of cable insulation volume enlargement. Then, more recent procedures for life and reliability estimation under time-varying electro-thermal stress are reported, focusing on thermal transients due to load cycles and voltage transients due to long temporary over-voltages (TOVs), superimposed switching impulses (SSIs), and voltage polarity reversals (VPRs). Results of the application of such procedures are also presented, with a discussion on their limitations and open issues.

Thermal aging is one of the main reasons for the degradation of insulation properties of high voltage cable. Dielectric properties and breakdown strength are important parameters to reflect the insulation performance of the cable insulation materials. In the work, the influence of thermal aging on dielectric and breakdown performance of the cable insulation layer was studied. Firstly, XLPE cable insulation samples were prepared and the thermal aging treatment was carried out. Secondly, the microstructure and molecular structure of XLPE samples under different thermal aging time were analyzed. The dielectric properties and breakdown characteristics of XLPE samples under different thermal aging times were characterized in macro aspect. Finally, the effects of different temperatures on the molecular microstructure of XLPE were studied. The results show that with the extension of thermal aging time, the microstructure of XLPE molecule is destroyed, the macromolecular chain is gradually cleaved, and the carbonyl absorption intensity increases. At power frequency, the breakdown strength decreases from 75.37 kV/mm to 62.18 kV/mm, the relative permittivity increases from 2.44 to 2.51, and the dielectric loss increases from 1.47 × 10−4 to 3.10 × 10−3. The free volume rate of XLPE molecules increases with the increasing temperature, and the mean square displacement gradually increases. The work has good guiding significance for the safe operation and condition assessment of high-voltage cables.

Predicting the remaining life and insulation failure of high-voltage distribution cables using statistical methods is essential for ensuring the reliability and safety of electrical power systems. Statistical techniques enable the identification of degradation trends by analyzing historical operational and diagnostic data. The paper examines the life expectancy of 10 kV Paper-Insulated Lead-Covered (PILC) cable insulation. The presented experiment was performed on both used and new cable samples. Presumptions of Weibull distribution parameters for random variables “breakdown voltage” and “breakdown time” are experimentally validated. The exponent of life expectancy for both used and new cable samples is obtained from experimentally derived parameters of the Weibull distribution. As a result, the dependence quantile for the breakdown probability of used and new cables is determined.

This article focuses on the effect of annealing process on the electrical properties of polypropylene (PP) insulation containing the <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-nuclear agent of WBG-II. The crystal form transformation during annealing at 140 °C is investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS). The results indicate that as the annealing time increases, part of <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-crystals transforms into <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>-crystals, followed by the increase in total crystallinity. As the annealing time increases from 0 to 8 h, the dc conductivity is reduced by an order of magnitude at 90 °C, the accumulation of space charges is suppressed, and the dc breakdown strength increases by 13.2%. During annealing, the molecular chains in some <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-crystals and amorphous rearrange and form <inline-formula> <tex-math notation="LaTeX">$\alpha $ </tex-math></inline-formula>-crystals, with higher molecular ranging regularity and better thermal stability. It is demonstrated that the crystal form transformation reduces the physical defects within the aggregate structure and increases the trap level, which contributes to the suppression of space charge and the improvement of the breakdown characteristics.

Dampness in the joint is a common defect of power cables, and the influence of moisture on the performance of the intermediate joint is very important. The electric field distribution of the joint is analyzed by simulation, and the XLPE sample is used as an experimental object to test the breakdown voltage under different damp levels. Simulation results show that in the composite interface outside the main insulation, the electric field at the water film is only 20%–60% of normal. However, the electric field around the water film generally increases, and as the degree of moisture increases, the electric field distortion becomes more serious, which is prone to inducing breakdown accidents. The electric field around the water film outside the conductor has no obvious distortion and will not directly induce accidents. Through the breakdown voltage experiment of the damp XLPE sample, it is found that the average breakdown voltage is 85%–94% of normal, and it decreases with the increase of moisture. The experimental results are consistent with the simulation results. The results can be used to guide the cause analysis of cable intermediate joint accidents.

… Assessments of aging and insulation degradation in power components are important to … components’ insulation. PD is initiated when the dielectric strength of localized insulation part is …

… requirements for electrical insulation, sealing … power factor over a range of frequencies (dielectric spectroscopy), analyzing physical insulation samples in a lab for polymeric breakdown …

In this article, the ±200-kV crosslinked polyethylene (XLPE) cable used in Zhoushan flexible dc transmission project is targeted. Three accelerated aging schemes of continuous electrical (CE) aging, intermittent electrical (IE) aging, and electrothermal (TE) combined aging are designed, and the simulation test platform is built accordingly. The lamellar samples, cut from the XLPE insulation of the spare cable, are aged for predetermined durations under different design stresses. The samples are tested for oxidation induction time (OIT), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermal stimulation current (TSC), space charge, dc conductivity, and dc dielectric strength, and the variation of various performance parameters are summarized. By analyzing the correspondence between the variation trend of each parameter and the aging process, the feature parameters that can effectively characterize dc XLPE insulation performance are determined, and the aging mechanism of dc insulation is explored. The results show that both electrical stress and thermal stress are important factors causing insulation aging, and their combined effect will significantly accelerate insulation deterioration. In addition, compared with the CE stress, the rise and fall of dc voltage will also aggravate the aging to a certain extent. Therefore, after the same time of continuous electrical stress, IE stress, and TE combined stress, the aging degree of XLPE samples increases in turn.

… domains, from electrical engineering to … on high-voltage insulation materials, narrowing its scope, an inherently arbitrary decision, to their role in high-voltage engineering within power …

… optimizing the machine process parameters and in determining the optimal raw material formulation in TIX cable … The aim of the study is to enhance revenue generation in the TIX cable …

… optimization. This paper introduces a new approach for ampacity calculations of long submarine power cables. As … Additionally, current characteristics in long AC cable conductors are …

In recent years, many projects have initiated to use superconducting cables to meet industrial challenges. More specifically, the integration of superconducting cables into DC railway network. This paper presents a comprehensive analysis of a single-pole superconducting cable and the losses caused by its associated components. The model used features a two-layer unipolar cable with a copper screen layer, a nominal current of 3 kA, and a nominal voltage of 1.5 kV. Furthermore, a coupled electric and thermal study is presented to assess the losses resulting from the terminations. The current flowing through the superconducting cable and terminations is simulated using a dynamic model of the railway network. Additionally, a detailed evaluation of the losses was conducted, along with a novel termination optimization approach which accounts for the true simulated current flow in the cable. This approach has considerably reduced the system's overall consumption, by 37%.

Industrial development and population growth have increased the need for higher-capacity power transmission lines. Aluminum conductor steel-supported (ACSS) conductors, a type of high-temperature low-sag (HTLS) conductor, are now widely used in new designs and reconductoring applications. ACSS conductors are preferred over traditional aluminum conductor steel-reinforced (ACSR) conductors due to their high strength, low sag, and excellent thermal stability. These attributes have garnered significant interest from researchers, engineers, and manufacturers. This paper provides a comprehensive review of the structure, properties, testing methods, and environmental behavior of ACSS conductors.

… conductor on round core (CORC) cables. However, it is crucial to note that the dissipation of AC losses in CORC cables … to simulate AC loss using the optimal incident angle. Addressing …

This article proposes loss and thermally optimized copper and aluminum structures for automotive electrical machines. A first batch of multiphysics optimization is performed parametrically for six different electrical conductor topologies. Then, a multiphysics—thermal and electromagnetic—hybrid parametric and topology optimization coupled with multiobjective differential evolution (MODE) and with an additional step of local search (LS) is proposed. The introduced topology optimization (TO) algorithm is explained in detail and applied to optimize electrical conductor geometries of pure Cu and AlSi10Mg. After that, the manufacturing by additive manufacturing (AM) of the most promising model is presented. The produced topology is benchmarked against a well-known fully rectangular structure. The proposed topology-optimized geometry has been found to improve conventionally manufactured electrical conductors at intermediate frequencies, around 600–800 Hz, and improves considerably at high frequencies, achieving a reduction in losses of 58% at 2000 Hz compared to a conventional rectangular copper structure.

… on the electric field intensity along the cable terminal umbrella skirt. It is found that both … materials and high dielectric materials can effectively optimize the electric field intensity of cable …

The Conductor on Round Core (CORC) cable has attracted wide attention with its strong current carrying capacity and high flexibility. Due to the limitation of soldering technology, joint resistances of a CORC cable are evitable, which can impact the performance of CORC cable significantly. In this work, a 3D model of a typical CORC cable with joint resistance is proposed based on H-formulation and heat transfer theory. Then, investigations are carried out on impacts of the joint resistance on the current distribution of CORC cable with DC transport current and AC transport current. Besides, the influence of Joule heat generated by the joint resistance on the temperature of the CORC cable is explored. The proposed model can serve as a powerful tool to analyze the electromagnetic-thermal behaviors of CORC cable in real applications.

… In this study, electrical and thermal analyses of a cable system … of the distance between the cables according to three different … Screen currents, screen voltages, cable temperatures, and …

… of high strength lightweight conductors rely on the optimization of alloys … optimal combination of strength and electrical conductivity is achieved for a ratio between the core and the wire …

… cables designed according to industry standards. It emphasizes the need for optimization in cable … The study highlights the interest in single-conductor cables and the associated issues …

Future collider accelerators will rely on high-temperature superconductors reaching high field up to 20 T and above. Among the existing high-temperature superconducting materials, the Rare-earth Barium Copper Oxide (ReBCO) tapes arranged according to the Conductor-on-Round-Core (CORC®) concept could be a viable solution to wound accelerator magnets such as Cosine Canted Theta (CCT) magnets. Dedicated experimental characterization of the critical current to quantify the degradation due to the winding process and operating conditions should proceed in parallel to the development of numerical models capable to reproduce and, in perspective, predict the cable performance. This paper presents the development of a new multi-physics model for a CORC® wound with ReBCO tapes together with its validation. The $T-A$ formulation has been used leveraging the high aspect ratio of tapes, suitably coupled with a conduction thermal model which for the first time properly accounts for the cable convective cooling. The model developed in this work can accurately simulate the thermal, electric and magnetic behaviors and the current sharing among tapes by using a set of self-consistent boundary conditions adopted for the first time in this kind of simulations. The model is verified and benchmarked against other well-established formulations on a set of test cases. The comparison of the computed $V-I$ characteristic of the straight cable to available experimental data shows that the main physics features of the cable are well captured by the model, including performance degradation due to cable tapering at the terminations.

The operating temperature of a submarine cable must be lower than its permissible limit to prevent degradation of the insulation material. Ground conditions influence the heat transfer between the cable and the surrounding soil, thereby affecting both the cable temperature and its economic efficiency. This paper investigates the effect of ground conditions on the thermal performance and economic efficiency of a three-core 220 kV AC XLPE submarine cable. A coupled finite element model based on electromagnetic, thermal, and pore water flow fields is developed and the effects of laying depth, initial temperature, soil thermal conductivity, and permeability on the thermal performance and economic efficiency of the cable are investigated via parametric studies. The results show that the conductor temperature increases with increasing laying depth, and this effect becomes more pronounced at greater laying depths. The conductor temperature increases linearly with increasing initial temperature and decreases nonlinearly with increasing soil thermal conductivity. When the soil permeability is greater than 10−11 m2, the conductor temperature decreases as the soil permeability increases. From a thermal-economic perspective, the economic efficiency of submarine cables can be improved by laying cables in soil with high thermal conductivity or decreasing the laying depth. Laying cables in soil with higher permeability to improve cost-effectiveness is effective only when the soil permeability exceeds 10⁻11 m2.

… , and the effects of load current, conductor spacing, wind speed on temperature field and fluid … of multi-conductor bundle is proposed. Finally, the optimized structure is obtained, and the …

The coupling relationship between space electronics systems is complex, and the signals of optoelectronic load cables are susceptible to interference, especially the early anomalous weak signals on a ground surface used for immediate remote sensing, which are more susceptible to coupling interference between cables. Ensuring a good grounding state for the cable shield is vital for reducing the interference suffered by cables and increasing the electromagnetic compatibility of the system. In this paper, we propose a shielding grounding optimization method for a spaceborne multi-cable shield, including a cable model and parameter extremization and parameter scanning simulation performed using CST, data processing and truth table transformation conducted using MATLAB, and logic expression extraction carried out using Multisim. The method can sort and classify the shielding effects of all the grounding states of multi-cable shields in batches, and ultimately output logical expressions specifying the mapping relationship between the shield grounding state and shielding effect, allowing the optimal shield grounding state to be quickly identified. Finally, the method was applied to a satellite-borne scanning mirror drive control system, and the effectiveness and accuracy of the method were verified by experimental tests.

Accurate current measurement in multicore power cables plays a pivotal role in maintaining grid stability. Noninvasive measurement methods are drawing more attention from researchers because the sensors are not electrically connected to the conductor, avoiding the problem of insulation. These methods are made by measuring the magnetic field generated by the current and then reconstructing the current from the magnetic field. As for the current measurement of multicore cables wrapped in ferromagnetic armor, due to the nonnegligible magnetic permeability of the armor, it is necessary to introduce the finite element method (FEM) for the computation, which significantly increases computational time. In this article, a magnetic field-current reconstruction algorithm with FEM precomputation is proposed to address this problem. This algorithm computes the positional current–magnetic field sensitivity (PCMS) in advance by using the parameters obtained from the sensor array calibration, and the conductor positional coefficients are obtained by linear interpolation of PCMS at the positions generated by the stochastic optimization. A measurement system for multicore power cable current is developed, with a 10-kV three-phase cable taken as the measurement object. The reliability of the system was verified through the built experimental platform and field test. The results show that the measurement error of multiple reconstructions within the 12-A range is 3.2%, and the max error in 23 h of continuous field measurement is 4.09%. Under the nonlinear magnetic permeability induced by high currents, the corrected reconstruction error remains below 2.5%. The proposed system shows potential for real-time grid monitoring and early fault detection.

Nuclear Instrumentation and Control (I&C) cables laying in a complex environment are prone to shield damage. And, the traveling wave reflection method can be used to detect and locate damage using the characteristic impedance change caused by I&C cable damage. Therefore, this paper establishes a quasi-coaxial cable shield characteristic impedance calculation model. And, it brings in the defective circumferential angle of the damage coefficient. Then, it builds a quasi-coaxial I&C characteristic impedance model approximation of the multi-core cable structure combined. Finally, the results of this paper through calculations and simulations are as follows. Firstly, the characteristic impedance of the cable with eccentricity e equal to 2.57 mm is stabilized at 37.795 Ω with increasing frequency. Second, the difference in the computational model is 3.88 Ω at 10 MHz of frequency, and a less than 3% difference in model approximation of a four-core cable at 5 MHz of frequency. Third, the calculation model can control the error of the characteristic impedance calculation result within 4 Ω within the defect angle of 270°. These results validate the reasonableness of the model.

Transient Overvoltage (TOV) poses significant safety risks to both substation equipment and personnel. Accurate measurement provides an essential reference for overvoltage protection. At present, the outer shield of the test cable used for potential leads is typically grounded at both ends to the ground grid (Method 1) to suppress external magnetic field interference. However, TOV events are usually accompanied by strong Ground Potential Rise (GPR), which causes interference currents on the shield due to Ground Potential Difference (GPD), leading to measurement errors. To address this issue, this paper proposes an alternative grounding scheme in which the outer shield is connected in parallel with a metal return wire (Method 2), thereby mitigating the impact of GPD. A numerical calculation model for evaluating the Shielding Effectiveness (SE) of the test cable under both interference magnetic fields and GPD was developed. The SEs of Method 1 and Method 2 were analyzed in both the frequency domain and under typical transient magnetic field waveforms in the time domain. The results show that, for each GPD frequency, there exists a characteristic interference magnetic field frequency f. When the magnetic field frequency is lower than f, Method 2 achieves significantly higher SE than Method 1; when it is higher than f, the SE of the two methods becomes nearly identical. Under typical magnetic fields, Method 2 consistently outperforms Method 1, with a maximum SE difference of 28 dB observed under a ringing wave condition. In practice, the selection of the test cable shield grounding method during TOV testing at generation and transformer substations should be based on the dominant frequency of the interfering magnetic field and the amplitude and frequency of GPD. For Transient Ground Potential Rise (TGPR) tests, Method 2 is strongly recommended.

Lightning-induced coupling effects pose substantial risks to the safety of power and signal transmission systems, particularly in complex electromagnetic environments. This study comparatively evaluates the shielding effectiveness (SE) of various shielded cables under two typical lightning surge waveforms. To simulate the coupling effects of lightning electromagnetic pulses, an experimental platform based on dual circular coils is established. The induced responses of various cable configurations are recorded and analyzed in time, frequency, and energy domains. The evaluated shielding strategies include single-ended grounding, double-ended grounding, and metal pipes with different coverage ratios. Results show that double-ended grounding markedly improves shielding performance under both waveforms, while multilayer shielding outperforms single-layer designs in suppressing both high-frequency and low-frequency interference. Note that, metal pipe shielding is only effective when fully covering the cable and grounded at both ends, yet underperforms compared to intrinsic cable shielding. Sensitivity analyzes further reveal the critical influence of geometric parameters on the induced response, with lower cable height drastically reducing magnetic loop coupling. Short pulses induce high transient currents and exert significant stress on magnetic coupling paths, while long pulses primarily trigger capacitive coupling. In addition, the energy accumulation analysis highlights the distinct temporal energy injection profiles of different surge waveforms, which informs protection strategies against both immediate impulses and prolonged stresses. These research findings offer practical guidance reference for the optimal selection and installation of shielded cables in lightning-prone environments.

: The measurement and decoupling of currents in multi-core power cables is a significant concern for power operators and holds immense potential for optimizing the monitoring and control of urban distribution networks. This paper aims to provide a widely applicable method for reconstructing current measurements. A YJLV22-3 ∗ 300 power cable is taken as an example, specifically focusing on the effect of steel armor on the measurement of the magnetic field generated by the current. Sample tests and field experiments are conducted to verify the spatial distribution of the magnetic flux density. Then the inverse problem of calculating current from the magnetic field is discussed. The defects of the existing methods are shown, and a new method for the inverse problem with the measured waveform of the tangential component of the magnetic flux density is proposed. The feasibility of the new method has been verified. The least-squares method is introduced to obtain the generalized inverse of the position coefficient matrix by maximum rank decomposition to extrapolate the conductor current matrix. A query method is proven to efficiently generate this matrix. Finally, the inverse problem is modeled as a stochastic search problem to compare the efficiency and stability of different algorithms, and CAM-ES performs best. The future research direction is toward developing and testing hardware measurement systems.

The shielding performance of cables with less weight has become a pivotal strategy for ensuring the device stability and reliability, especially in harsh operational conditions. This article develops nickel-coated aramid fiber (Ni@AF) composites as a novel cable shielding material and designs shielding layer structures using a proposed simulation-driven framework, through which excellent cable shielding performance is achieved. Specifically, the Ni@AF composite possesses an average shielding effectiveness (SE) of up to 65.4 dB at 4–12.4 GHz, and the cables using Ni@AF are predicted to show 87.51% increase in the time domain shielding effectiveness (TDSE) and 46% reduction in weight, as compared to the cables using conventional metal materials. Moreover, the TDSE of the proposed cable structure remains highly stable, with a variation less than 3.08% across different pulse widths, and also displays extremely low sensitivity to the polarization patterns and incident angles, with difference variation less than 17.38% and 17.72% respectively. The practicality of the proposed shielded cable structure, including its incident condition insensitivity and adaptability in high-power electromagnetic pulse environments, has been confirmed by measurements and real-world scenario simulations.

… armored shielded multi-core parallel cables with a length of 1 meter was built in the shielding … layer, the shielding layer, the insulation layer, and the inner core wire. The 3D model of the …

The shielding effectiveness of secondary cables is a key feature in improving the level of EMC in substations. However, the shielding effectiveness of the secondary cable armor layer is still an unclear issue, and the armor layer’s grounding method is not explained in the relevant IEEE and IEC standards. In this paper, the shunt capacity and grounding methods of shield and armor layers were tested in the laboratory and substation to clarify the respective shielding performance. The results show that the armor layer also has the same shunt capacity as the shield; and the method of double-end grounding of the armor layer, single-end grounding of the shield on the control room side can effectively reduce the core wire induced voltage. Finally, through test analysis and comparison, some engineering suggestions were put forward.

To address the significant challenges of testing the electromagnetic pulse (EMP) radiation effects on the shielded multicore wire coupling channel in large-scale weapon systems, a theoretical model has been developed that utilizes bulk current injection (BCI) as an equivalent substitute for high-field-intensity electromagnetic radiation. This model establishes equivalence based on the equal terminal responses of each wire pair under both radiated and injected conditions. The equivalent relationship between the injection source and the radiation field intensity for each wire pair is linear and uniform. This relationship, being independent of the terminal impedance at the equipment under test (EUT), enables the calculation of the equivalent injection waveforms. The equivalent testing method for strong EMP radiation effects is proposed and demonstrated by experimental validation. The average correlation coefficient of response curves for each wire pair in the pass-through load simulating the EUT test exceeds 0.9. The maximum error observed in the airborne computer effect test is 1.48 dB. The proposed method indicates that achieving equivalence for one wire pair’s terminal response under radiated conditions ensures equivalence for the remaining wire pairs as well, demonstrating applicability to nonlinear systems.

The induced voltage, apart from being a concern for human safety, also becomes a concern for the continuous operation of plants, where the electrical equipment is connected via numerous wires and cables for control purposes. The induced voltage beyond permissible limits may intervene with the proper functioning of the signalling and controlling devices of the plant and result in unscheduled interruptions. It is a well-known phenomenon of electromagnetism, that when the static conductor is situated within a changing magnetic field or a conductor moves within a static magnetic field, a voltage is induced in the conductor and thus, induced voltage is inevitable in conductors in alternating current fields. In this paper, we have attempted to study induced voltage considering variations in cable constructions aiming to derive a solution to mitigate or minimize induced voltage in control cables. We have come across enquiries from cement plants towards the requirement of control cables limiting induced voltage up to 50V to prevent malfunctioning of their signalling and sensing equipment which sometimes may be catastrophic, which has triggered this study.

… was conducted on multi-core I&C cables with varying severities of external shielding damage. … Each type of defect affected the cable’s outer sheath, insulation, and shielding, revealing …

… The findings show that connecting a load reduces terminal voltage but increases entrance voltage on the cables, and that grounding the cable shielding layer significantly mitigates …

The development of medium-voltage direct current (MVDC) cable systems for wide-body all-electric aircraft (AEA) requires insulation technologies capable of operating reliably under reduced-pressure environments. Conventional underground cable insulation, designed for atmospheric conditions, exhibits degraded partial discharge (PD) and dielectric performance at low pressure, limiting its applicability to aerospace systems. This work presents a controlled experimental comparison between a conventional single-layer extruded insulation system and a micro-multilayer multifunctional electrical insulation (MMEI) architecture, in which all cable components are kept identical except for the insulation. The MMEI system is implemented with only 10% of the baseline insulation thickness to evaluate the effectiveness of insulation architecture in enhancing performance. PD characteristics and dielectric strength are experimentally evaluated under DC voltage at atmospheric pressure and 18.8 kPa. Results show that the MMEI-based cable exhibits higher PD inception voltage (PDIV) and maintains a detectable PD extinction voltage (PDEV) under reduced pressure, unlike the conventional cable. Furthermore, despite its significantly reduced thickness, the MMEI system demonstrates a substantial increase in dielectric breakdown strength, withstanding voltages exceeding 20 kV compared to below 5 kV for the conventional design under low-pressure conditions. These findings demonstrate that insulation architecture, rather than thickness alone, governs performance in MVDC aerospace cables. The results highlight the potential of MMEI systems to enable lighter, more compact, and higher-performance cable designs for future electrified aviation platforms.

This paper goes one step forward in the life estimation of HVDC cable insulation under load cycles by introducing for the first time a microscopic model of charge conduction and transport i.e., Bipolar Charge Transport BCT model for electric field calculation inside the insulation thickness. The paper firstly includes the development and the validation of BCT model with that found in literature. Then, the parameters of the developed BCT model are optimized using Pulsed Electro-Acoustic PEA space charge measurements. Followed by the integration of the developed, validated and optimized model into the electric field calculation for life estimation of a 500 kV DC-XLPE insulated cable subjected to Type Test load cycles according to Cigre Techical Brochure 852. The developed microscopic model is compared to the macroscopic models already found in the literature. The microscopic model shows a comparable electric field inversion similarly to macroscopic models. However, the behavior of the microscopic model is noticed to be different under heating and cooling load cycles. In hot cable, the maximum electric field stabilizes at different amplitude and position inside the insulation thickness in both models. This investigation has been carried out in the framework of the HEU-NEWGEN research project.

We present a novel topography scanning system developed to XLPE cable core monitoring. Modern measurement technology is utilized together with embedded high-performance computing to build a complete and detailed 3D surface map of the insulated core. Cross sectional and lengthwise geometry errors are studied, and melt homogeneity is identified as one major factor for these errors. A surface defect detection system has been developed utilizing deep learning methods. Our results show that convolutional neural networks are well suited for real time analysis of surface measurement data enabling reliable detection of surface defects.

Loss allocation of the three different components (conductor, sheaths and armor) of solidly bonded three-core separated lead-sheathed armored cables, frequently employed in offshore wind farms, is challenging due to the lack of accurate enough analytical expressions in the IEC standard. Also, loss allocation through experimental tests leads to inaccurate results since it is based on questionable assumptions. This paper improves both the IEC formulae and experimental methods by means of different analytical corrections in the conductor and sheath loss expressions. To this aim, an ad hoc application interface (Virtual Lab) based on 3D numerical simulations (finite element method) has been developed. This tool virtualizes and automates different test setups to emulate, in few seconds, the most employed experimental procedures in this type of cable. The analytical corrections have been derived from an in-depth analysis of a first set of 368 cables, ranging from 30 to 275 kV. The new loss expressions were successfully applied to a second set of 645 armored cables of quite diverse features (voltages from 10 to 275 kV, sections and dimensional parameters), hence bringing a general framework for any kind of three-core armored cable.

The great expansion in offshore power plants is raising the concern regarding the cumulative effect of the electromagnetic field emissions caused by submarine power cables. In this sense, owners are required to predict these emissions during the permitting and consenting process of new power plants. This is a challenging task, especially in the case of HVAC three-core armored cables due to their complex geometry. Customarily, 2D approaches based on the finite element method (FEM) have been employed for evaluating the magnetic field emissions caused by these cables. However, inaccurate results are obtained since the phase conductors and armor twisting is omitted. This work develops, for the first time in the literature, an in-depth analysis of the magnetic field caused by this type of cable through an ultra-shortened 3D-FEM model, which is also faced to experimental measurements taken on an actual 132 kV, 800 mm2 three-core armored cable. Relevant conclusions are derived regarding the impact of the cable design on the magnetic field emissions, including material properties, as well as single and double-layer armors, presenting the proposed model not only as a valuable tool for predicting purposes, but also for optimizing cable design in terms of magnetic field emissions.

Over the past decade, significant progress has been made in the field of loss and rating calculations for armoured three-core cables. This development was prompted by an industry realization that the applicable international standards often overestimate losses, leading to unnecessarily bulky and more expensive cables. Starting with first-principles, this paper presents an accurate analytical formula for armour losses in three-core cables. The formula has undergone rigorous validation against 3D Finite Element Analysis (FEA) and demonstrate excellent accuracy. In the specific cases examined, the largest deviation from FEA results in terms of armour loss is approximately 2.4 percent for fully armoured cables. Although this study specifically focuses on armour losses, it establishes the groundwork for precise loss calculations in armoured three-core cables, including the conductor and screen losses. And the work presented here formed the basis for the complete loss calculations presented in the CIGRE Technical Brochure 908.

The review begins with an exploration of acceptable cable types guided by local standards. It then investigates typical cable faults, including insulation degradation, conductor faults, and ground faults, providing insights into their characteristics, causes, and detection methods. Furthermore, the manuscript surveys the latest publications and standards on DSP techniques in fault location spanning various algorithms used. This review provides a comprehensive understanding of low and medium-voltage cables, fault types, and DSP techniques. The findings contribute to improved fault diagnosis and localization methods, facilitating more accurate and efficient cable fault management strategies

This paper analyzes different ways to simulate electromagnetically three-core armored cables in 3D by means of the finite element method. Full periodic models, as lengthy as 36 m, are developed to evaluate the accuracy when simulating only a small portion of the cable, as commonly employed in the literature. The adequate length and boundary conditions for having the same accuracy of full periodic models are also studied. To this aim, five medium voltage and high voltage armored cables are analyzed, obtaining the minimum length of the cable that may be simulated for having accurate results in shorter time and with less computational burden. This also results in the proposal of a new method comprising the advantages of short geometries and the applicability of periodic boundary conditions. Its accuracy is compared with experimental measurements and the IEC standard for 145 kV and 245 kV cables. The results show a very good agreement between simulations and measurements (errors below 4 %), obtaining a reduction in the computation time of about 90 %. This new method brings a more effective tool for saving time and computational resources in cable design and the development of new analytical expressions for improving the IEC standard.

Development of REBCO cables that carry high electrical current in high magnetic field is crucial for future large-scale magnet applications. This experimental work presents the critical current measurements of two different REBCO cables by a test facility at the National High Magnetic Field Laboratory (NHMFL). The simple-stacked cable is made by the NHMFL by stacking 21 REBCO tapes without soldering. The Conductor-on-Round-Core (CORC) cable provided by Advanced Conductor Technologies has 21 layers of REBCO tapes with 2 tapes/layer. The test facility consists of a 12 T split solenoid magnet with 15 cm bore providing transverse field to the samples, a superconducting transformer (SCT) as a current source providing up to 45 kA current. Special attentions were paid to fabrication of solder joints between REBCO cables and the SCT output. The voltage-current traces were measured as a function of magnetic field at 4.2 K, from which the critical currents are determined. The details of this measurement are discussed.

Power cables have complex geometries in order to reduce their AC resistance. The cross-section of a cable consists of several conductors that are electrically insulated from each other to counteract the current displacement caused by the skin effect. Furthermore, the individual conductors are twisted over the cable's length. This geometry has a non-standard symmetry - a combination of translation and rotation. Exploiting this property allows formulating a dimensionally reduced boundary value problem. Dimension reduction is desirable, otherwise the electromagnetic modeling of these cables becomes impracticable due to tremendous computational efforts. We investigate 2D eddy current boundary value problems which still allow the analysis of 3D effects, such as the twisting of conductor layers.

Due to recent advances, the numerical analysis of submarine three-core armored cables can nowadays be developed through the finite element method (FEM) in a small slice of the cable. This strongly reduces the computational burden and simulation time. However, the performance of this ultra-shortened 3D-FEM model is still to be fully assessed with experimental measurements. This paper focuses on this validation for an extensive variety of situations through the experimental measurements available in the specialized literature for up to 10 actual cables. In particular, it deals not only with relevant calculations at power frequency, like the series resistance and inductive reactance or the induced sheath current, but also with other aspects never analyzed before through 3D-FEM simulations, such as the zero sequence impedance, the magnetic field distribution around the power cable, as well as side effects due to the nonlinear properties of the armor wires. All this considering different armoring and sheath bonding configurations. Results show a very good agreement between measured and computed values, presenting the ultra-shortened 3D-FEM model as a suitable tool for the analysis and design of three-core armored cables, and opening the possibility to reduce the need of extensive experimental tests in the design stage of new cables.

Recently, large offshore wind power plants have been installed far from the shore, using long HVAC three-core armored cables to export power. Its high capacitance may contribute to the appearance of unwanted phenomena, such as overvoltages or resonances at low frequencies. To adequately assess these problems, detailed and reliable cable models are required to develop time-domain/frequency-domain analyses on this type of cables. This paper presents, for the first time in the literature, an assessment on the performance of 3D finite element method-based (3D-FEM) models for developing frequency-domain analyses on three-core armored cables, confronting simulation results with experimental measurements found in the literature for three real cables. To this aim, a simplified ultra-shortened 3D-FEM model is proposed to reduce the simulation time during frequency sweeps, through which relevant aspects never analyzed before with frequency-domain 3D-FEM simulations are addressed, such as total losses, induced sheath current, magnetic field around the power cable, positive and zero sequence harmonic impedances, as well as resonant frequencies. Also, a time-domain example derived from the frequency-domain analysis is provided. Remarkable results are obtained when comparing computed values and measurements, presenting the simplified ultra-shortened 3DFEM model as a valuable tool for the frequency-domain analysis of these cables.

We establish mathematical bounds on the chain, ABCD and immittance matrices of a multiconductor transmission line, based on the Telegrapher's equation. Closed-form expressions for those matrices are also presented. Existing results that hold on the imaginary axis are extended to the complex plane, without reliance on a diagonalizability assumption that is prevalent in the literature. Therefore, the results remain valid under arbitrary arrangements of the conducting wires, which include electrical faults. The analysis ultimately reveals important system-theoretic implications of the Telegrapher's equation, which are of general relevance to control, power systems, and signal processing involving multiconductor transmission lines.

We investigate the electromagnetic interactions of cable harnesses in the time domain. We present a novel model that allows for curved cables, extending the standard assumptions typically made in transmission line modeling. The cables are described by the telegrapher's equations, the classical model for transmission lines, driven by input signals implemented through appropriate boundary conditions, such as imposed voltages at cable ends. The cables interact via electromagnetic radiation; the latter is determined by Maxwell's equations. This interaction is incorporated into the model through boundary conditions imposed on the electromagnetic field. The resulting coupling between the transmission lines and Maxwell's equations is energetically consistent. In particular, we show that the coupled system satisfies a global power balance.

Building on the recently published work "Modeling of radiating curved cables via coupled telegrapher's and Maxwell's equations", which introduces a model for the interaction between electromagnetic fields and radiating (possibly curved) cables, we analyze the qualitative properties of the resulting dynamical system. The model features inputs and outputs given by the currents and voltages at the cable ends, while the state comprises the corresponding distributions along the cables and the electromagnetic fields in the surrounding domain. We show that the autonomous dynamics (i.e., with zero input) generate a strongly continuous semigroup and establish sufficient conditions for well-posedness, meaning continuous dependence of the state and output trajectories on the inputs and initial conditions.

The electrification and ongoing energy transition lead to systematic changes in electricity loading and variability in power systems. Distribution systems were designed for regular operating patterns, assuming constant low loading. Now, operators need to assess whether their assets can withstand more, as well as time-varying loading. Operating the system at or near its ampacity potentially accelerates thermal ageing, so the question arises: 'how much can one operate at the limits while keeping maintenance and failures low?' This paper introduces a novel approach that derives a time-varying Weibull approximation of failure rates using thermal models and provides a shortcut method to quantify maintenance implications under time-varying loading for heterogeneous MV cable populations. The case studies investigate a dataset from Denmark and the Oberrhein Medium Voltage (MV) system in Germany, studying ageing assets and the interplay with loading, and replacement paradigms of two different cable insulation types. The studies demonstrate that a small fraction of 25% of old, low-quality cables leads to 82% of failures, and 1.4% of the time of highest loading can cause 46% of cable ageing. The case studies also demonstrate that maintenance needs may be between 10-300 times higher under future loading conditions associated with the energy transition, specifically in networks that have older PILC cables. This paper provides a new tool for operators to plan maintenance under more realistic, future operating conditions.

Given the importance of monitoring the operational status of high-voltage cables in coal mines, this study investigates the application of intelligent sensing technology to the online monitoring of such cables. Taking an actual coal mine as a case study, a three-layer architecture high-voltage cable monitoring system was designed. The system employs high-frequency current sensors and distributed optical fiber temperature sensors to achieve real-time acquisition of partial discharge signals and temperature distribution data. Data analysis and fault diagnosis are performed through a combined approach of edge computing and cloud computing. The research results demonstrate that the system can accurately identify cable insulation defects and potential overheating hazards, with a diagnostic accuracy exceeding 95%, thereby significantly enhancing the reliability of power supply in mines.

The electrical collector system (ECS) plays a crucial role in determining the performance of offshore wind farms (OWFs). Existing research has predominantly restricted ECS cable layouts to conventional radial or ring structures and employed graph theory heuristics for solutions. However, both economic efficiency and reliability of the OWFs heavily depend on their ECS structure, and the optimal ECS cable layout often deviates from typical configurations. In this context, this paper introduces a novel reliability-based ECS cable layout planning method for large-scale OWFs, employing a two-stage stochastic programming approach to address uncertainties of wind power and contingencies. To enhance reliability, the model incorporates optimal post-fault network reconfiguration strategies by adjusting wind turbine power supply paths through link cables. To tackle computation challenges arising from numerous contingency scenarios, a customized progressive contingency incorporation (CPCI) framework is developed to solve the model with higher efficiency by iteratively identifying non-trivial scenarios and solving the simplified problems. The convergence and optimality are theoretically proven. Numerical tests on several real-world OWFs validate the necessity of fully optimizing ECS structures and demonstrate the efficiency of the CPCI algorithm.

An accelerated deployment of renewable energy sources is crucial for a successful transformation of the current energy system, with wind energy playing a key role in this transition. This study addresses the integrated wind farm layout and cable routing problem, a challenging nonlinear optimization problem. We model this problem as an extended version of the quota Steiner tree problem (QSTP), optimizing turbine placement and network connectivity simultaneously to meet specified expansion targets. Our proposed approach accounts for the wake effect $-$ a region of reduced wind speed induced by each installed turbine $-$ and enforces minimum spacing between turbines. We introduce an exact solution framework in terms of the novel quota Steiner tree problem with interference (QSTPI). By leveraging an interference-based splitting strategy, we develop an advanced solver capable of tackling large-scale problem instances. The presented approach outperforms generic state-of-the-art mixed integer programming solvers on our dataset by up to two orders of magnitude. Further, we present a hop-constrained variant of the QSTPI to handle cable capacities in the context of radial topologies. Moreover, we demonstrate that our integrated method significantly reduces the costs in contrast to a sequential approach. Thus, we provide a planning tool that enhances existing planning methodologies for supporting a faster and cost-efficient expansion of wind energy.

Power cables have complex geometries in order to reduce their ac resistance. Although there are many different cable designs, most have in common that their inner conductors' cross-section is divided into several electrically insulated conductors, which are twisted over the cable's length (helicoidal symmetry). In previous works, we presented how to exploit this symmetry by means of dimensional reduction within the $\mathbf{H}-\varphi$ formulation of the eddy current problem. Here, the dimensional reduction is based on a coordinate transformation from the Cartesian coordinate system to a helicoidal coordinate system. This contribution focuses on how this approach can be incorporated into the magnetic vector potential based $\mathbf{A}-v$ formulation.

Superconducting arrays often require specialized, high-density cryogenic cabling capable of transporting electrical signals across temperature stages with minimal loss, crosstalk, and thermal conductivity. We report improvements to the design and fabrication of previously published superconducting 53 wt% Nb-47 wt% Ti (Nb47Ti) FLexible coAXial ribbon cables (FLAX). We used 3D electromagnetic simulations to inform design changes to improve the characteristic impedance of the cable and the connector transition. We increased the center conductor diameter from 0.003 inches to 0.005 inches which lowered the cable characteristic impedance from $\sim$60 $Ω$ to $\sim$53 $Ω$. This change had a negligible impact on the computed heat load which we estimate to be 5 nW per trace from 1 K to 100 mK with a 1-ft cable. This is approximately half the heat load calculated for the smallest commercially available superconducting coax. We also modified the transition board to include a capacitive coupling between the upper ground plane and signal traces that mitigates the inductive transition. We tested these changes in a 5-trace, 1-ft long cable at 4 K and found the microwave transmission improved from 6 dB to 1.5 dB of attenuation at 8 GHz. This loss is comparable to commercial superconducting coax and 3$\times$ lower than commercial NbTi-on-polyimide flex cables at 8 GHz. The nearest-neighbor forward crosstalk remained less than -40 dB at 8 GHz. We compare key performance metrics with commercially available superconducting coax and NbTi-on-polyimide flex cables and we share initial progress on commercialization of this technology by Maybell Quantum Industries.