For assessment of the insulation performance of high-voltage (HV) equipment installed in extra-high-voltage (EHV) systems, switching impulse voltage tests are performed in an HV testing laboratory. The waveform parameters of the switching impulse vol...
Knowledge of lightning impulse (LI) voltage distribution over transformer windings during the design stage of the transformer is very important. Specific design differences in inductive voltage transformers make the transient analysis approach differ...
The recent interest in the development of nanomaterials has led researchers to the study of their electrical properties and the applications that they may have as insulating materials. One of these applications is the use of nanofluids as electrical...
Owing to the increased use of antibiotics, drug-resistant strains, including those that are resistant to the antibiotic vancomycin, have emerged, which has become a major problem. In Japan, sewage treatments consist of sterilization with chlorine; ho...
Dermanyssus gallinae, a parasitic mite that subsists on the avian blood of chickens, poses a considerable threat to the poultry industry. D. gallinae infestation can result in a plethora of detrimental effects for the host birds, including decreased...
Due to the increased utilization of electric converters feeding rotating high voltage motors, their insulation is subject to transient impulse and high frequency oscillating voltages. In corresponding life time experiments with repetitive oscillating...
This paper presents an effective technique based on an artificial neural network algorithm utilized for circuit parameter identification in lightning impulse generation for low inductance loads such as low voltage windings of a power transformer, a l...
This study examines and compares the breakdown and aging properties of five insulating liquids. Additionally, the influence of different voltage polarities on these properties was analyzed to investigate the effect of aging on polarity behavior under...
In this paper, an effective simulation method for lightning impulse voltage tests of reactor and transformer windings is presented. The method is started from the determination of the realized equivalent circuit of the considered winding in the wide...
This paper introduces an effective and non-iterative technique for the determination of full lightning impulse voltage parameters in high-voltage tests. In the waveform parameter determination, the base curve parameters are determined on the basis of...
Transformer oil does not only serve as an insulating liquid, but also in removing heat from the windings and cores. Mineral oil (MO) has been widely used in transformers for more than 150 years. Recently, researchers have attempted to search for alte...
Electrical tree is an important factor in the threat of the safety of cross-linked polyethylene (XLPE) insulation, eventually leading to the electrical failure of cables. Polycyclic compounds have the potential to suppress electrical treeing growth....
The well-known circuit for the generation of lightning impulse voltage (LIV) on low-inductance loads was introduced by Glaninger in 1975, and the circuit component selection was proposed by Feser. However, the circuit and the approach for the compone...
This study presents findings on the influence of gap length distance on the lightning impulse breakdown voltage of three dielectric liquids of different chemical origins. The liquids were tested in a model electrode system with a quasi-uniform electr...
The environmentally friendly insulating gas C4F7N/CO2 has become a popular alternative to the insulating gas SF6 in recent years. The internal structure of electrical equipment should be taken into account in normal operation, and its electric field...
The widely distributed interconnects in printed circuit boards (PCBs) easily couple with high voltage under the action of electromagnetic pulses, which leads to insulation failure. In this study, the dielectric breakdown characteristics of four typic...
Breakdown (BD) voltage is significant in high-voltage power electric machines. Currently, BD voltages are mainly predicted by the semi-empirical formula in strongly inhomogeneous electric fields. However, the equation could not be applied for electro...
Oil-pressboard/paper insulation materials are essential in transformers for ensuring their safe and stable operation, primarily due to their roles in spatial electric field distribution and charge migration mechanisms. Current spatial distribution an...
The impulse breakdown attributes are of rudimentary importance in the insulation coordination in the gas-insulated switchgear (GIS). The critical voltage waveshape for the insulation is the surge over voltages. Usually, such over-voltages will emerge...
Metal contaminants can distort the surface electric field of the tri-post epoxy insulator and cause serious surface charge accumulation, significantly reducing the insulation performance of the insulator under the superimposed DC and lightning impuls...
Power capacitors suffer multiple impulse voltages during their lifetime. With the multiple impulse voltage aging, the internal insulation, oil-film dielectric may deteriorate and even fail in the early stage, which is called accumulative effect. Henc...
Practical experience in the use of high power impulse magnetron sputtering (HiPIMS) technology has revealed that output bias current depends on the total energy output of the cathodes, which means that bias voltage settings do not necessarily match t...
The design, construction and characterization of a photonic voltage transducer with a lightning impulse protection for distributed measurements on medium voltage (MV) networks (11 kV) was presented in this paper. The sensor prototype, comprising a co...
The influx of a switching impulse during DC steady-state operations causes severe electrical stress on the insulation of HVDC cables. Thus, the insulation should be designed to withstand a superimposed switching impulse. All major manufacturers of DC...
Nano-modification is a prospective method for improving the electrical properties of transformer oil. In most situations, transformer oil combined with cellulose paper is used to construct an insulation system for power equipment, such as power trans...
In transmission lines, the discharge characteristics of long air gaps significantly influence the design of external insulation. Existing machine learning models for predicting breakdown voltage are typically limited to single gaps and do not account...
The Frequency Response Analysis approach (FRA) is useful in the fault diagnosis of transformers. However, its usefulness in diagnosing any potential sources of Partial Discharge (PD) in transformers has not been thoroughly investigated so far. In thi...
Arresters on electric multiple units (EMUs) usually experience premature aging under a high-frequency voltage and impulse current. In addition, they lead to overheating faults when subjected to the high-frequency overvoltage of electric railways. Thi...
The detection of Partial Discharge Inception Voltage (PDIV) is vital for evaluating the insulation performance of random-wound inverter-fed motor stators. However, existing research on the impact of impulse parameters on PDIV patterns and their under...
Liquid insulation is used in high voltage equipment such as power transformers as both dielectric medium and coolant. Breakdown in liquid insulation tends to be governed either by streamer initiation under more uniform fields, or by streamer propagat...
High-voltage electric field measurement technology has certain applications in electric field measurement of power systems, but due to the limitation of its measurement accuracy and bandwidth, it cannot be used for the measurement of lightning-impuls...
Multiple valve unit (MVU), which converts AC to DC and DC to AC, is one of the key elements of high voltage DC (HVDC) transmission. Therefore, the insulation design of MVU against overvoltage should be considered for the stable and reliable operation...
Under operating conditions, metallic particle contaminants inside Gas-Insulated Switchgears (GIS) represent a major threat that can initiate partial discharges (PD) and lead to insulation failure. To investigate the discharge patterns under combined...
This work aims to provide information about the deposition of gold via bipolar high-power impulse magnetron sputtering (HIPIMS) in order to identify suitable process parameters. The influences of voltage, pulse length and the kick-pulse on an argon&n...
This article deals with the influence of temperature on the lightning impulse breakdown voltage (LI BDV) of mineral oil in a non-uniform electric field. The experiments were performed in point–plane electrode arrangements under a standard light...
External environmental factors have no effect on the breakdown performance of the internal gap, leading to the anti-icing and anti-storm features of the internal-gap lightning protection device (ILPD). In this paper, a test platform is created to stu...
Partial discharge (PD) detection under oscillating switching impulse (OSI) voltage was performed on three types of insulation defects, including a protrusion on a conductor, a particle on an insulator surface, and a void in an insulator, which are th...
Even though the streamer process can be identified in nanoseconds and microseconds through experimental measurements, the breakdown time of air discharge is still unknown. The instability of electrons is suspected to be an attachment-instability phen...
The present study aimed to develop the electrical performance of outdoor insulators using a nano-TiO2 coating for railway electrification systems. The prototype design of porcelain insulators with normal coatings and using a nano-TiO2 coating is base...
This paper is devoted to a comparison study of the breakdown voltage of CO2, N2, and SF6 gases, and CO2–SF6 and N2–SF6 mixtures under different voltage waveforms, namely AC, DC, and lightning impulse voltages, in point–plane and sphere–sphere electro...
Partial discharge (PD) measurement and its pattern recognition are vital to fault diagnosis of transformers, especially to those traction substation transformers undergoing repetitive traction load shocks. This paper presents the primary factors indu...
A simplified and accurate model of a surge arrester used in the residual voltage test is proposed in this paper. With the help of a genetic algorithm, the measured impulse current and residual voltage waveforms are utilized to determine circuit param...
This article presents the results of comparative studies on streamer propagation and breakdown in a point-insulating plate electrode system in mineral oil and two ester liquids. The studies were performed for a 10-mm gap and a positive standard light...
The interest in developing new fluids that can be used as dielectric liquids for transformers has driven the research on dielectric nanofluids in the last years. A number of authors have reported promising results on the electrical and thermal proper...
As one of the key technologies to solve the problem of high short-circuit current, the fault current limiter (FCL) has become a research hotspot in China and abroad. The overvoltage and protection measures of the FCL are the key technologies for its...
Environmentally-safe high-power impulse magnetron sputtering (HiPIMS) technology was utilized to deposit chromium films. This research focused on the influences of the HiPIMS pulse widths on the microstructure of films deposited at different depositi...
The dimension and surface state of shielding fittings in ultra high voltage direct current (UHVDC) converter station valve halls have a great influence on their surface electric field and switching impulse characteristics, which are important paramet...
An increasing number of different types of dielectric liquids are appearing on the market. This is undoubtedly related to sustainable development goals. This paper presents comparative studies of the lightning impulse breakdown voltage (LIBV) of six...
This paper presents the design, development, and characterization of a low-cost and environmentally friendly high-voltage divider optimized for on-site calibration up to 850 kV. Unlike traditional dividers that rely on oil or SF6 for insulation, both...
Failures are sometimes attributed to the deterioration of insulating oil, with contamination by cellulose particles. Such contamination lowers the dielectric strength of the oil. This study investigates the effect of cellulose contamination on the im...
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