The authors investigated the ingredient detection technique of silicone rubber based on the Terahertz spectrum. For this purpose, 18 diverse high-temperature vulcanised silicone rubber (HTVSR) formulations were customised, 8 of which are used as calibration set while the rest 10 as prediction set. Based on the Beer-Lambert Law, the partial-least-square (PLS) regression model and the least-squares support-vector

For the space charge measurement method with optical excitation for electrical insulation, the distortion of the excitation laser on the measurement signal and the accumulation of space charge have not been discussed before. Both experiment and simulation results show that three types of distorted components introduced by optical excitation can lead to distortion of the upper interface signal. Further

Insulation systems in high-voltage electric machines play a pivotal role in the reliable operation and longevity of the equipment. Mica-based insulation materials have proven to possess and maintain excellent dielectric properties in the long run and prevent premature insulation degradation. Numerous qualifications tests, such as voltage endurance, are outlined in IEC and IEEE standards. The authors

Line-commuted converter (LCC)–voltage source converter (VSC) hybrid high voltage direct current (HVDC) transmission system is an innovative technology, the existing LCC and VSC protection require setting, and it is difficult to be directly applied in the LCC–VSC hybrid HVDC, which is a serious problem in practical engineering. A novel linear regression density peak clustering (LRDPC) approach is introduced

When some new-type sensors are subjected electromagnetic interference (EMI), the traditional standard can no longer serve as the guidance for their EMI protection. Therefore, it is necessary to evaluate the complexity of the new sensing equipment's suffering from electromagnetic interference. A hybrid method of feature extraction and complexity evaluation of Electromagnetic Interference signals based

Ultra-wideband (UWB) microwave sources driven by specialised pulsed power generators have experienced a considerable development in the last decade due to their wide domain of new applications such as defence or counter-terrorism activity. The authors present the main findings of a research dedicated to the development of a pulsed power-driven electromagnetic field source for disabling improvised explosive

C6F12O is proposed to be one potential eco-friendly insulation gas to replace SF6. However, the assessment of its decomposition properties and the compatibility with metal electrodes in discharge faults is still challenging, which greatly hinders the development of its insulation and arc-extinction applications. Herein, a theoretical method is proposed to reasonably address the discharge effects on

The cross-linked polyethylene insulated cables with corrugated aluminium-sheathed are widely used in urban power systems. Recently, a new type of power cable fault has emerged, primarily due to defects in the buffer layer. However, there is a notable lack of effective evaluation methods for these defects in high-voltage (HV) cables. Initially, a theoretical analysis of the gas generation mechanism

Understanding the impulse discharge behaviour of natural ester (NE) is crucial for its safe application in high-voltage transformers. The ionisation potential (IP) of triglycerides plays a significant role in the process of molecular ionisation during impulse discharge for NE. The correlation coefficients between molecular size, frontier orbital, electrostatic potential, polarity, and IP were analysed

Long-term exposure to moisture leads to a gradual deterioration of performance and reduced service life of glass fibre-reinforced epoxy resin (GFRP) material in composite insulators. Therefore, it is necessary to analyse the moisture absorption characteristics of GFRP material and the evolution of damage to their internal interface properties. Moisture absorption tests on GFRP rod material used in

The influences of thermal cycling ageing on structures and insulation performances of polypropylene (PP)/elastomer/boron nitride (BN) nanocomposites are investigated. The Melt blending method was used to prepare the nanocomposites, in which propylene-based elastomer (PBE) or ethylene-octene copolymer elastomer (EOC) was contained for comparison. Then, the samples were treated using a thermal cycling

The potential of using eco-friendly thermoplastic polypropylene (PP)-based insulation for high voltage direct current (HVDC) cable has been widely investigated but much less work on the PP-based semiconducting screen (SC). Considering a long service life (>30 years) under high temperature and high electrical stress is required for typical HVDC cables, and investigations on the effect of antioxidant

The real-time simulation of the modular multilevel converter-based high-voltage direct current (MMC-HVDC) transmission system has become a popular research topic. However, in order to meet the real-time performance, the real-time simulation technology will cause additional simulation errors for MMC-HVDC, especially on its frequency characteristics. Therefore, a parallel multi-rate simulation scheme

To solve the problem of the energy harvesting (EEH) effect of the condition monitoring devices power supply on the transmission line is not ideal. The authors designed three kinds of EEH schemes based on AC electric field induction, which can effectively improve the output power of load power supply. The EEH principle of each scheme was analysed in detail, and the influence factors such as the shape

The authors investigate the effects of nanofillers with varying band-gap energies on the space charge properties, breakdown field strength, and bulk resistivity of epoxy (EP)-based composites. Additionally, the molecular orbital distribution of both the epoxy resin and nanofillers were examined through density functional theory. Experimental results indicate that the space charge accumulation within

Various dielectric response processes in the oil-paper insulation are sensitively affected by the insulating states (ageing degrees and moisture contents). However, the existing research is still incomplete in revealing the microscopic mechanisms of various dielectric response processes in oil-paper insulation with different insulating states. Given this issue, the genetic algorithm is first adopted

When a high-speed train approaches the insulated phase-splitting section embedded between neighbouring power supply arms, the vacuum circuit breaker (VCB) installed on trains must be disconnected to maintain the traction power supply system as a no-load condition for completing phase-switching action, as the train passes through the phase-splitting section depending on its inertia. However, when operating

A dual-frequency (DF) dielectric barrier discharge, excited by the superposition of a 50 Hz low frequency (LF) and a 5000 Hz intermediate frequency (IF), is proposed to enhance discharge. The effect of the LF voltage component on the breakdown behaviour of the DF discharge during different periods has been studied both experimentally and numerically. The number of high-current pulses rises as the LF

Electrical tree degradation is one of the main causes of insulation failure in high-frequency transformers. Electrical tree degradation is studied on pure epoxy resin (EP) and MgO/EP composites at frequencies ranging from 50 Hz to 130 kHz. The results show that the tree initiation voltage of EP decreases, while the growth rate and the expansion coefficient increase with frequency. Moreover, the bubble

Commutation failure (CF) is one of the most common issues in line-commuted converter-based high voltage direct current systems (LCC-HVDC), leading to critical power system security and stability problems. Accurate and rapid identification of CF is crucial to prevent subsequent CF in HVDC systems. However, the existing CF identification methods are lack of the required accuracy and speed. The relationship

Accurate calculation of short-circuit electromagnetic force is crucial for both mechanical strength check and the optimal design of gas-insulated transmission lines (GIL). Since the full 3D numerical simulation method is highly time-consuming, a novel lightweight 2D multi-slice electromagnetic field-circuit coupled method for computing transient electromagnetic force is proposed, where appropriate

A high-temperature superconducting (HTS) dynamo flux pump can inject DC currents into closed-loop HTS magnets without contact. It enables the realisation of current-lead-free or even through-wall charging systems for high-field applications such as nuclear magnetic resonance/magnetic resonance imaging (MRI) magnets, fusion reactors and accelerators. Researchers have proposed many simulation models

With the widespread application of composite insulators in transmission lines, exploring the accumulation mechanism of pollution particles on composite insulator surfaces is of importance to ensure the safe and steady operation of the power system. Addressing the current theoretical shortcomings, this study categorises the accumulation process of particles on the insulator surface into three stages

In order to accurately predict the content and variation trend of dissolved gas in transformer oil and guide the condition maintenance of power transformers, a combined prediction model based on multi-information fusion is proposed and its effectiveness is analysed. First of all, based on the possibility of pathological and missing historical sample data, a detection and filling method based on variable

Transformers may suffer multiple short-circuit impacts during long-term operation, and axial instability is one of the typical types of serious accidents caused by short-circuit faults. The axial instability form of the winding-block structure is analysed, and the dynamic solution of the winding short-circuit electromagnetic force is obtained by establishing the three-dimensional magnetic-circuit-force

Developing low-carbon gas insulated transmission and distribution equipment is essential to achieve the ‘carbon peak, carbon neutralisation’ or ‘net-zero’ in the power industry. Scholars have carried out various research on the eco-friendly insulating gas (such as C4F7N, C5F10O) and next-generation SF6-free equipment to gradually reduce the utilisation of strong greenhouse gas SF6. The cover of this

The eco-friendly insulating gas perfluoroisobutyronitrile (C4F7N) is potentially used in gas-insulated transformers (GIT) to replace sulphur hexafluoride (SF6). However, evaluation of the long-term insulation reliability and gas–solid interface discharge decomposition characteristics of the gas–solid film insulation structure in GIT is indispensable. The authors simulated the gas–solid film insulation

A novel control scheme is presented to eliminate the negative effects of communication disturbances, which introduces active disturbance rejection control (ADRC) in the control strategy design to achieve the objectives of the restoration of the bus voltage and the sharing of the power even in the presence of disturbances and delays in communication. Simultaneously, its dynamic disturbance decoupling

The insulation performance of oil paper insulation is significantly affected by moisture such that monitoring moisture content is important. However, it is difficult to obtain the moisture content accurately due to its dynamic change under multi physical fields. Studying the moisture transportation in oil paper insulation under multi physical fields becomes a vital method in solving the problem. A

Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical utilities. Dissolved gas analysis (DGA) is frequently used for this purpose. However, DGA lacks the necessary level of accuracy to identify all equipment faults, particularly in their initial stages of degradation. Also, it does not have the capability for real-time monitoring

Accurate surface charge inversion can guide the research on surface modification of insulators in GIS/GIL. The current inversion algorithms have disadvantages of high computational cost and low accuracy. Based on that, the integral equation method (IEM) is proposed to calculate the transformation matrix. Compared with the traditional analytical method (AM), IEM has a simple calculation process. The

Outlet short circuit on the low-voltage (LV) side and winding inter-turn short circuit faults are hazardous to transformer operation. To investigate the formation mechanism of winding insulation faults of distribution transformer, ANSYS Maxwell was used to build a coupled magnetic field-circuit model with the same structural dimension as the actual distribution transformer. An outlet short circuit

In the past three years, a number of oil-immersed ultra-high-voltage shunt reactors have experienced discharge defects when being put into operation, resulting in an overload of acetylene. However, detecting and identifying these discharge defects caused by switching impulse voltage is challenging under steady-state conditions. This poses unpredictable and difficult-to-assess safety risks for the longterm

Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military, industrial, and aerospace engineering. The oriented hexagonal boron nitride (hBN) composites, due to excellent thermal and electrical insulating properties, show a potential application in high-voltage power equipment, while the surface flashover performance of hBN composites dependent on oriented hBN

As a typical failure phenomenon in transformers, sulfur corrosion has garnered significant attention in the field of high-voltage engineering. Grain boundary character distribution (GBCD) copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular corrosion. In this study, the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various

The strain clamps and leading wires are important components that connect conductors on overhead transmission lines and conduct current. During operation, poor contact between these components can cause abnormal overheating, leading to electric failures and threatening power system reliability. Recently, the use of unmanned aerial vehicles equipped with infrared thermal imagers for strain clamp and

A simulation analysis and an experiment are carried out to investigate how the gap difference between the breaks of a direct current vacuum circuit breakers with multi-breaks (MB-DC VCB) caused by the mechanism dispersion of the breaker influences the distribution of TRV among the breaks. An interruption model of MB-DC VCB, combining the continuous transition model, is established to analyse the rising

Accurate simulation of lightning-induced overvoltage for overhead distribution lines is helpful to prevent lightning trip accidents. An electromagnetic return-stroke model was used to represent lightning and then a 3D finite-difference time-domain (FDTD) method was adopted to simulate the lightning-induced overvoltage on a distribution line without a field-line coupling model. How lightning-induced

An arc is the high-temperature discharge plasma produced in the opening process of mechanical switches, which directly affects the breaking capability of a hybrid DC circuit breaker. According to the physical mechanism of an electric arc, the construction of an arc model for simulation analysis is an important technical means in the electrical field. In this study, based on the theory of magneto hydrodynamics

During the operation of high-voltage cables, external stress and residual stress can affect the aggregated structure of insulating materials and lead to significant deterioration in their electrical performance. To investigate the evolution characteristics of the electrical properties of cross-linked polyethylene (XLPE) under mechanical stress, this paper explains the relationship between the aggregated

Wang, P., et al.: Impact of air pressure variations on electrical vehicle motor insulation. High Voltage. 8(5), 1011–1019 (2023). https://doi.org/10.1049/hve2.12346 The authors wish to bring to the readers' attention the following error in the article by Peng Wang, Chaofan Yu, Shakeel Akram, Ziyuan Fan, Wenhuan Zhao, ‘Impact of air pressure variations on electrical vehicle motor insulation’. Equation (4)

The main part of oil-immersed power equipment is oil-paper insulation. At lower ambient temperatures, transformer oil will become viscous. As a result, compared to those at room temperature or operating temperature, the frequency domain dielectric properties of oil-paper insulation at low temperatures are drastically different. For evaluating the insulation condition of electrical equipment, it is

The flashover in vacuum is a rapid interfacial discharge across the insulator surface when subjected to high applied voltage. Here a theoretical model covering above-surface processes is introduced. The model calculates the flashover threshold in vacuum, with revised secondary electron emission avalanche theory and improved desorbed neutral transport model. The model serves as the first part of an

The semi-conductive shielding layer is an important part of the high-voltage cable, playing a role in uniform electric field and reducing the air gap at the interface. The overall performance of the cable is affected by the semi-conductive shielding layer with different base resin composition. The matrix resins of ethylene-vinyl acetate (EVA), ethylene-ethyl acrylate (EEA) and ethylene-butyl acrylate

The analysis of the eddy-current field in the wound core widely used in the field of transformer energy conservation is taken as the theme. Adopting the homogenisation idea to consider the unique geometry of the wound core and features of its equivalent multi-stage circular cross-section magnetic boundary, a homogeneous model consisting of a columnar material with continuous homogeneous electromagnetic

Low temperature plasma stands at the forefront of green and clean energy technologies, showcasing remarkable versatility across a wide array of applications including material processing, water splitting, methane conversion, and plasma medicine. To fully harness the potential of this technology, it is imperative to deepen our understanding of the physics underlying various discharge structures. This

Because DC conductivities of oil-paper materials can be easily affected by electric field and temperature, the electrical properties under electro-thermal coupling of oil-paper materials should be considered when optimising the insulation structure of valve-side winding of the converter transformer. Based on the finite element multi-physical field coupling simulation, the multi-objective optimisation

The micro-defects in epoxy-based insulation materials generate a local high electric field which results in continuous degradation, seriously endangering the insulation system of gas-insulated switchgears. A highly sensitive detection technique is reported for micro-defects of insulation pull rods based on the photon counting (PC) technique. The results demonstrated that for an epoxy-based insulation

The unsatisfactory insulating properties of solid–gas interfaces seriously restrict the development of high-voltage electrical equipment and threaten their power supply stability. Electron-beam irradiation (EBI) can effectively improve the surface flashover voltage of dielectrics. However, the underlying mechanism of EBI in tailoring the surface trap and improving the flashover voltage remains unclear

The moisture generated by the ageing of the oil-paper insulating system can easily lead to the deterioration of the performance of the insulating paper. In order to alleviate the impact of moisture on the performance of the insulating paper, we developed a kind of lipophilic hydrophobic self-repairing cellulose insulating paper (new insulating paper) based on the ternary system of polytetrafluoroethylene

Dielectric barrier discharges (DBD) are widely utilised non-equilibrium atmospheric pressure plasmas with a diverse range of applications, such as material processing, surface treatment, light sources, pollution control, and medicine. Over the course of several decades, extensive research has been dedicated to the generation of homogeneous DBD (H-DBD), focussing on understanding the transition from

Due to the increasing power system capacity, the interruption of large fault currents has gradually become a major challenge in power systems. At the moment, such currents are interrupted mainly via circuit breakers based on the method of active current commutation. However, these types of circuit breakers tend to be costly and oversized. One possible alternative—a fuse-based circuit breaker with current

The step-up resonant converters are widely adopted to provide high voltage in kV-level for electric propulsion system due to their high efficiency, low mass, modularisation, and high-power density. The bipolar Cockcroft-Walton voltage multiplier (BiCWVM) is a major circuit that steps up the voltage in the resonant converter. However, the diode non-linearity in BiCWVM can introduce self-sustained quasi-periodic

A wireless signal transmission technology based on acoustic carrier is proposed, which overcomes the limitation of electromagnetic signal shielding and shows great potential for in-site monitoring of sliding electrical contact used in gas-insulated switchgear (GIS)/gas-insulated transmission line (GIL). Here, the state parameter of the sliding electrical contact is modulated onto the frequency domain

Hydrogen generated by water electrolysis is considered as one of the most promising protocols to partly replace the roles of traditional fossil fuels. However, high-performance electrocatalyst satisfied with the industrial requirement still faces significant challenges. Low-temperature plasma contains numerous high-energy ions, electrons and other reactive species, which can provide a highly reactive

Bisphenol F epoxy resin (EP) is often used in terminal current lead insulation of superconducting equipment because of its good insulation performance, high mechanical strength, good toughness at cryogenic temperatures, and resistance to cold shock and heat shock. However, due to the wide temperature range of 80–300 K and the strong electric field, the EP-N2 interface is prone to surface flashover

The lifetime model of turn-to-turn insulation in inverter-fed motors is studied. A lifetime model has been built by considering the effect of inverter-generated high voltage rise rate (dv/dt up to 20 V/ns). This model is followed by the generalised probabilistic model, in which the lifetime is proportional to the nth power of the voltage rise rate. Moreover, by investigating the effect of voltage rise

Trace hydrogen sulphide (H2S) could reflect the severity of insulation faults in gas-insulated switchgear (GIS), therefore, accurate and fast detection of low-concentration H2S is important for on-line monitoring, fault diagnosis, and state evaluation in GIS. Ag-Ti3C2Tx chemiresistive-type sensors were fabricated via drop-coating with self-reduction synthesised Ag-doped Ti3C2Tx. The as-prepared sensors

Rubber-based composites based on ethylene propylene diene monomer (EPDM) with excellent non-linear electrical conductivity are preferred to serve as reinforced insulation in cable accessories, which can self-adaptively regulate electric field distribution and avoid electric field concentration due to the non-linear conductivity. The conductive carbon nanotubes (CNT) are filled into EPDM to improve

Ice monitoring methods were applied for 110 kV and above transmission lines with tangent towers. However, the change in the vertical span is not considered, and a significant difference lies in the tower-conductor structure of 10 kV transmission lines. For this reason, a proposal is made about the ice monitoring method for the 10 kV transmission line with tangent tower in alpine landform, which includes