The buffer layer defects of high-voltage crosslinked polyethylene (XLPE) cable occur frequently, which makes the detection method become the focus to be studied. Here, the broadband impedance detection technology for the buffer layer defects of high-voltage XLPE cables with corrugated aluminium sheath is investigated. There are nine cable samples, including new and defective ones. Some of the defective

Mineral oil is the most frequent insulating liquid used in oil-immersed transformers for electrical insulation and heat dissipation. However, oil-based nanofluids are becoming more popular in scientific research as they have proved to have better dielectric and thermal characteristics. When applying these nanofluids into actual transformers, they would be exposed to thermal and electrical stresses

Dynamic ageing process of cross-linked polyethylene (XLPE) cable insulation under combined electro-thermal effect is investigated by the construction of theoretical analysis model and the practice of operation-simulated ageing test. Firstly, theoretical analysis model is constructed from time and spatial dimensions. From the time dimension, in the light of the impeding trend of internal stress to external

Composited cable terminals are critical for reliable power delivery of traditional and traction power supply systems. During its operation, the cable terminal continually undergoes complex circumstances where humidity, temperature, field strength, mechanical stress and other factors continuously change at different levels. In extreme cases, defects or even failures may occur in the cable terminals

Partial discharges (PD) are the ‘cancer’ of electrical insulation. Insulation design and mitigation of PD-induced degradation should be based on good knowledge of PD phenomena. In that regard, a significant body of knowledge has been built up from concerted research across the world in past decades and on various aspects of PD phenomena under various conditions. However, the work is far from being

In modern megacities, stray currents from metro systems intrude into multiple transformers' neutral points becoming a potential threat to the high-capacity transformers. Neutral current anomalies are exacerbated in unprotected substations when we instal guards at single stations. This paper presents a system protection strategy for multiple substations affected by stray currents in modern megacities

Composite polymer dielectrics have strong electrical, mechanical, thermal and environmental properties but experience both high electric fields and harsh environmental conditions as outdoor insulation. The present investigation of the stress-strain characteristics and morphology of the fracture cross-section reveal the risk of a weakly bonded interface between the aluminium hydroxide (ATH) filler and

The electromagnetic (EM) rail launcher G10 insulator is prone to delamination damage during launch, which affects the service life of the insulator. Through the secondary development of ABAQUS® commercial finite-element software, an EM-structure coupling launch dynamics model considering projectile-barrel coupling is established. The simulation indicates that the transverse swing of the projectile

In the process of coping with energy and environmental protection issues, technologies such as energy materials, energy devices, and energy systems have made great progress. With excellent performance, film capacitors play an increasingly important role in energy-related fields. With the increase of application scenarios and the continuous development of film material technology, it is urgent to establish

The composite insulation composed of cross-linked polyethylene (XLPE) and silicone rubber (SiR) is common in high voltage direct current cable accessory installation. However, the space charge accumulation, especially the interfacial charge accumulation of XLPE/SiR, poses a serious threat to the safe operation of cable accessories, and its charge transport mechanism is still unclear, especially at

Most reactors for non-thermal plasma excitation are capacitive to pulse generators. The density and temperature of electrons in plasma are dominated by the discharging currents which are proportional to the pulse edges. However, adjusting the pulse edges is quite challenging since the switching speed and the inductance and capacitance in the discharging loops dominate them. This study proposes a drive

Surface charge accumulation is the potential criminal for surface insulation failure on spacers under direct current (DC) voltages. The existence of thermal gradient posing the difficulty of surface charge regulation. This study proposes a temperature-dependent adaptive conductivity coating technique for surppressing surface charge accumulation under electro-thermal coupling field. A two-dimensional

The degradation of dielectric properties of polypropylene (PP) at high temperature affects the operational stability of metallised film capacitors. This study presents a method to improve the high-temperature dielectric performance of PP through long-chain branching modification and regulating the crystalline properties. Different amounts of nucleating agents were added to long-chain branched polypropylene

With the increase in applied voltage and the decrease in volume, integrated electronic modules have become electrostatic sensitive. ZnO microvaristors doped silicone rubber (SiR) composite, with electric field-dependent conductivity, shows promising prospects for solving the electrostatic problem. In this study, 20 vol% to 50 vol% ZnO/SiR composite films, filled with 10–30 μm ZnO microvaristors, were

In this paper we investigated SF6 decomposition behaviour of typical insulation defects in gas-solid insulated converter transformer valve-side bushing under partial discharge (PD). Additionally, we compared the results with that of gas insulated switchgear (GIS). The results indicated that SF6 decomposition behaviour varies with the insulation defects type. For metal protrusion defects, the proportion

Engineering experience shows that for transformers with long service life and serious moisture exposure, the inter-turn paper insulation inside the winding will precipitate bubbles under the condition of electric field and conductor heating, which will endanger the equipment insulation. In order to explore the influence factors of bubbles formation in the moist insulating paper of transformers, based

High-voltage withstand tests are essential for electric equipment like power transformers, electric cable lines, gas insulated switchgears etc. The partial discharge (PD) measurement for such equipment under applied high voltage is also required at the same time. Pulse Width Modulation (PWM)-based variable frequency power supply (VFPS) finds wide applications in the series resonance high-voltage testing

Compared to the traditional aircraft, electrification of power system in aircraft has potential to revolutionise the aviation industry. Typically, more-electric aircraft (MEA), even all-electric aircraft has been developed and delivered to decrease the greenhouse gas emission and increase the energy efficiency. The next generation of MEA will operate at high voltage to facilitate the transfer of significant

Long-term thermal ageing might have impacts on the physicochemical properties of cross-linked polyethene (XLPE) cables, thereby influencing their electrical behaviours, such as electrical treeing initiation and growth. The main objective of this work is to report the effects of thermal ageing on the electrical treeing behaviours (initiation and growth) in XLPE cable insulation. For this purpose, the

The phenomenon of transformer failure caused by oil-sulphur corrosion of oil₋paper insulation system has always been concerned by scholars. Irgamet 39 is the most used metal passivator for inhibiting sulphur corrosion. However, Irgamet 39 causes abnormal dissolved gas in oil during the process of exerting anti-corrosion effect. Herein, the gas production mechanism of Irgamet 39 and its long-term corrosion

The electric field imposes a significant effect on ice accretion on the insulator. The impact of an AC electric field on insulator icing in an artificial climate chamber has been addressed. Compared with AC, DC electric field exerts an attraction on supercooled water droplets, which is more detrimental to the power system. Moreover, the icing on energised insulators is rarely studied in the natural

In this study, three kinds of radical scavenger Chimassorb 944, Tinuvin 622, and Tinuvin 770 are used to suppress the growth of electrical trees in cross-linked polyethylene (XLPE) with transient superimposed voltage under the temperature gradient. The tree morphology, tree length, accumulated damage, and time to breakdown are used to investigate the effect of radical scavenger on the electrical treeing

Automatically and accurately detecting the self-blast state of glass insulators is of great significance to operation and maintenance of transmission lines. To solve the shortcomings of the existing open-loop cognitive models to detect the self-blast state of glass insulators, this study explores a mixed data augmentation-based intelligent recognition method to detect the self-blast state of the glass

Ethanol solution as a disinfectant has been widely used in various fields. However, it has a significant bactericidal capability only when the volume fraction of ethanol is around 70%–75%. For such high concentration of ethanol solution, it has an irritating smell. When it is used for applications such as wound disinfection, it causes a stinging sensation. Low concentrations of ethanol solution are

The development of positive and negative streamers in a point-to-plane gap filled with air and nitrogen at various pressures (50–200 kPa) and voltages (8–25 kV) was studied. A four-channel intensified charge-coupled device (ICCD) and a streak-camera were used. Electrical parameters were measured with high resolution (10 GHz). An original method of measuring a displacement current caused by a streamer

Furfural content in oil is considered as an effective parameter to evaluate the ageing state of oil-immersed transformers. In previous thermal ageing experiments at 130°C, we found that moisture increment in oil-paper system makes more furfural distribute in oil. However, the microcosmic mechanism of moisture effect on furfural diffusion from paper to oil is still unknown, and the furfural equilibrium

Unclean air discharge refers to the discharge phenomenon of a large number of polluting gases, droplets or solid particles floating in the air, which will cause insulation breakdown and safety accidents for the power transmission equipment that have been left outdoors for a long time. In order to investigate the effects of particle concentration, particle size and dielectric constant on DC breakdown

The development of a high-current DC breaker is very important for the protection of the expensive superconducting magnet. A kind of an economic switch called pyrobreaker, which is driven by explosive detonation waves, has been used as the backup quench protection due to its inherent reliability and fast response. A prototype pyrobreaker with a special structure that can withstand and break 100 kA

Organophilic groups of coupling agents can be the key factor for the electrical performance of Boron Nitride (BN)/meta-aramid composite paper. In this article, four types of triethoxy-silane coupling agents with different organophilic groups, including mercapto-propyl (MP), glycidylether-propyl (GP), amino-propyl (AP) and trideca-fluoro-octyl (TFO) were studied. The structural and electrical properties

Flashover is prone to occur in composite insulation structures such as vacuum-solid and gas-solid, which are universally employed in high-voltage power equipment. In this study, a high flashover strength and superhydrophobic coating were proposed by constructing porous surface morphology. Octadecyl trichlorosilane (OTS) particles were prepared by hydrolysis condensation reaction, and thereafter sprayed

A triple-objective optimal design method for AC filters in high voltage direct current (HVDC) system based on an improved multi-objective evolutionary algorithm based on decomposition (MOEA/D) is proposed. A triple-objective optimisation mathematical model including total harmonic distortion (THD) on AC side voltage, investment cost of AC filters and telephone harmonic form factor (THFF) is established

The winding current harmonic content of converter transformer in operation is rich. However, affected by harmonics, the radial vibration characteristics are quite different from the power transformer, structural loosening and deformation caused by winding vibration are more prominent. Therefore, in view of the influence of current harmonics on axial and radial vibrations, this study builds a 3D winding

This study set out to systematically investigate the structural characteristics of plane electrohydrodynamic jets through the particle image velocimetry (PIV) techniques. Due to the wide range of applied voltages and electrode gaps under various experimental conditions, an assessment of the image quality and a statistical analysis of the velocity fields are first performed to ensure the validity of

The 2 × 2 couplers, as a demodulation core of the fibre optic sensing system, have been extensively employed in fibre optic sensors for partial discharge (PD) detection of power equipment. However, the unstable demodulation sensitivity and low signal-to-noise ratio (SNR) of such a system are still unsatisfactory in engineering. This work uses a distributed feedback fibre laser as the sensor and employs

As the core equipment of transmission and distribution hubs, the operational status of gas-insulated switchgear (GIS) is closely linked to the safety of the power system. Recently, X-ray digital imaging technology has been extensively used in GIS equipment fault detection. However, the X-ray image of GIS is blurred, which is not conducive to the detection of tiny defects. Thus, a super-resolution method

Tri-post insulators in gas-insulated transmission line (GIL) are usually fabricated with high mass fraction of micron aluminum oxide (Al2O3), which will unavoidably settle under the action of gravity during the preparation process and seriously affect the uniformity. A model of filler sedimentation in epoxy resin composite materials was proposed based on the particle size analysis and Stokes' Law.

All-solid-state switches are one of the core components of pulsed power supply systems. However, the voltage level of a single switch is limited. By optimizing the chip structure, the voltage level of a single switch can be improved. Due to the immaturity of the production process and the positive correlation between the blocking voltage and the on-resistance of the switch, it is difficult to improve

In order to reveal the effect of insulating nano film on the insulation strength of SF6 gas gap, SiO2 nano film was deposited on the electrode surface by the plasma-enhanced chemical vapour deposition technique. The power frequency breakdown characteristics of SF6 gas under Cu and Al electrodes were obtained before and after coating. The results showed that when the Cu electrode was coated, the breakdown

The physical mechanism of leader formation and development is not well understood. In this study, we present experimental and simulation results obtained with a 10 m long air gap discharge. A 10 m outdoor discharge experiment is carried out to obtain the current, voltage, and optical image during the leader discharge process. Four different impulse voltages were applied to the rod-plane gap. The measured

Diagnosing insulation intrinsic ageing is essential for preventing insulation failure of submarine cables, and in case of failure, helping in any decision about maintenance actions. In this study, a novel aged cable diagnosis approach based on high-voltage frequency domain spectroscopy (HV-FDS) with broader frequency width is proposed to analyse the high-field polarisation characteristics and conductivity

Stable triggering of acquisition devices is critical to accurately measure electromagnetic transients, especially for very fast transient overvoltages (VFTOs). A highly stable and low-cos t self-trigger method for transient measurement is proposed. An integrated low-voltage arm module was developed to synchronously realise the triggering and VFTO measurement. The trigger branch was developed using

Pseudospark discharge is a low-pressure high-voltage pulsed discharge with hollow electrodes, and the overall discharge experiences several distinctive sub-phases. The instability phenomena, characterised by the sudden oscillations or distortions of discharge voltage and current, restrict the applications of pseudospark discharge. This study presents an investigation into phase transitions and instabilities

Polymer dielectrics with excellent energy storage performance at high temperature are urgently needed in advanced applications, such as hybrid electric vehicles, smart grid and pulsed power sources. Polyetherimide (PEI), which is supposed to be the most promising candidate among polymer dielectric materials, displays a limitation for high-temperature polymer dielectrics owing to the rapidly decreasing

Metallised polypropylene film capacitors (MPPFCs) are widely used in power electronics and are generally degraded by elevated temperatures. This work aims to determine the relationships between the structural changes of MPPFC and the microstructural variations of the PP film during the thermal ageing of MPPFC at 100°C for 38 days. The capacitance of MPPFC has a slight decrease during thermal ageing

The surface-enhanced Raman scattering (SERS) substrates enable a highly sensitive detection of furfural in the transformer oil. However, detection substrates with long-term stability are still extremely challenging. In this work, we anchored the thiol-containing coupling agents 2, 5-dimercapto-1, 3, 4-thiadiazole (DMTD) and 1, 4-benzenedithiol (BDT) on the surface of bubble copper (B-Cu) and flower-like

The optical morphology of discharge is the main characteristic parameter describing the physical process of the discharge, and the luminescence behavior is inextricably linked to the motion behavior of charged particles. Since the Trichel discharge in air is a weak ionization event occurring on the sub-nanosecond time scale, micron space scale and accompanied by weak luminescence, the current experimental

Incorporating positive temperature coefficient (PTC) ceramic particles into polymers provides a prospective alternative solution for suppressing severe electric field distortions caused by negative temperature coefficient (NTC) of electrical resistivity within polymer insulation in high voltage direct current cable. The effect of the Curie temperature of PTC particles on the inhibition of the NTC effect

Cellulose insulation paper is the main component of oil-paper insulation systems in oil-immersed transformers. However, the poor thermal conductivity and thermal stability of the cellulose can lead to thermal ageing. It is critical to address this issue by improving the performance of cellulose, nano-SiC-modified cellulose models were established by molecular simulation, while nano-SiC composite papersheets

Thermal characteristic is one of the key performances of dry-type on-board traction transformer (D-OBTT), which directly affects the operation safety of the new generation electric multiple units. However, due to the particularity of train-induced wind cooling mode of D-OBTT, the existing efficient thermal modelling methods cannot be used under fluctuating air velocity and load. A time-saving transient

Composite cross-arms have the advantages of high lightning resistance but impose onerous requirements on mechanical and insulation reliability. Traditional glass fibre composites fail to meet the needs of practical applications. Basalt fibre exhibits better mechanical properties and stability than glass fibre and has potential application value. This study aims to evaluate the feasibility of its application

Online detection of insulation defects the decomposition products of SF6 plays a key role in ensuring the safe operation of the gas-insulated switchgear (GIS) equipment. The pristine TiO2 (1 0 1) modified by Ni cluster (1–3 Ni atoms) is used as a new gas-sensing material to study its gas-sensing characteristics to the characteristic decomposition products of SF6: SO2, SOF2, and SO2F2. Through density

To investigate how the multiphase structures affect the electrical conductivity in semi-crystalline polymer composites, herein, an accurate multiphase content calculation method is proposed and verified, which combines amorphous phase information in broadband dielectric spectroscopy and crystalline phase information in differential scanning calorimetry. Taken aluminium hydroxide (ATH) filled silicone

The failure of electrical equipment directly or indirectly caused by overheating has become one of the main reasons for equipment accidents. The real-time condition monitoring method of electrical equipment based on digital twin (DT) has received extensive attention and is considered as a technology with great engineering values and excellent application prospects. However, the current calculation

Calculated parameters (soil layer resistivity, soil layer thickness, and the number of soil layers) of horizontally layered soil are usually obtained based on the measured apparent resistivity under different measurement distances, which are significant for the design, operation, and maintenance of grounding grids. Most existing calculation methods of soil parameters are just trying to make the calculation

Due to the complexity of test procedures and the high cost of measurements, the mechanism of the decay-like fracture is unclear, which brings hard concepts and the small sample problem. Therefore, it is intractable to establish accurate data-driven models. To solve the above mentioned problems, this paper proposes a data-driven modeling method based on radar graph mapping models and virtual sample

Recent studies have shown the in vitro neuro-protective functions of atmospheric pressure plasma (APP) against multiple pathological injuries during ischaemic stroke (IS). However, whether APP treatment exerts a therapeutic effect on a rat IS model remains unclear. Here, on the basis of needle-to-ring dielectric barrier discharge, an atmospheric pressure plasma jet (APPJ) was designed, with the Helium

In this study, three kinds of inorganic fillers are chosen and filled into ethylene-propylene-diene monomer (EPDM) matrix, including silicon carbide, copper calcium titanate (CCTO), and vanadium dioxide (VO2). The electrical properties of the three modified composites at different temperatures have been systematically studied. The intrinsic conductance behaviours of different inorganic fillers on the

In order to elucidate mechanical impacts affecting the insulation strength of thermal-ageing oil-impregnated pressboards, we perform mechanical degradation experiments of impacting forces that are represented as the winding-suffered stresses on thermal-ageing oil-paper insulation in transient short-circuit of transformer. Water content, degree of polymerisation (DP), partial discharge inception voltage

This paper reports on the individual and synergistic influence mechanisms of nano-silica (SiO2) and voltage stabilizers on partial discharge (PD) resistance of polypropylene blended with ethylene-octene copolymer elastomer. The SiO2 nanoparticles and three types of voltage stabilizers, that is, benzoin, 4,4′-dimethoxybenzil, and 3-aminobenzoic acid are selected as fillers to prepare samples. PD is

C4F7N is considered to be the most potential alternative gas for SF6. However, harmful decomposition by-products generated by the discharge or overheating faults will pose threat to safe operation and service life of gas insulated equipment (GIE). Herein, we investigated the adsorption performance of γ-Al2O3 on C4F7N and its decomposition products to evaluate the possibility of using it as by-products