Phenomena of the pantograph arcing have become a challenge for further development high-speed electrified railway system. Despite large attention that has been paid to radiated electromagnetic interference, materials ablation as well power-quality decline resulted from arcing, specific dynamics with high time resolution are still in absence. In this paper, phenomena laboratory simulation system were experimentally studied by photography. Synchronized electrical voltage and current waveforms...

Pantograph-catenary (PC) arc has become an obstacle for the further development of high-speed railway. Understanding on underlying physical mechanisms PC dynamics is still far away from satisfactory; therefore, researches both experimental and numerical aspects are urgently required. This paper focused dynamic characteristics during pantograph lowering process by simulation method. A model was established based classical magnetohydrodynamics theory, with temporal evolution considered. The...

SHP1 is a non-receptor protein tyrosine phosphatase extensively expressed in hematopoietic cells, exerting pivotal role as an immunosuppressive factor. Our previous studies have suggested that can undergo liquid-liquid phase separation (LLPS). In this study, the SHP1-C455S mutant, commonly utilized biochemical assays due to its lack of catalytic activity, unexpectedly exhibited remarkably robust ability for LLPS. Since C453S mutation has been previously shown potentially induce...

The partial discharge (PD) classification for electric power equipment based on machine learning algorithms often leads to insufficient generalization ability and low recognition accuracy. To solve the problem, this article develops an improved Wasserstein generative adversarial network with gradient penalty (WGAN-GP) data augmentation model. WGAN-GP model can generate samples supplement low-data input set in PD source classification. First, conditional generation is trained various new are...

Polyimide nano-composite film (Kapton 100CR) is a special type of engineering plastic film, which widely used in turn insulation form-wound inverter-fed motor. Partial discharge (PD) caused by high-frequency surge impulse one the key factors leading to premature failure motors. Aging experiments on samples under repetitive bipolar square voltage were carried out this study. Experimental results show that, presence PD, damage structure polyimide concentrated surface layer sample. Moreover,...

In order to investigate the effects of inorganic nanofillers on electrical properties polyimide (PI), PI/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> nanocomposites films were prepared via in-situ polymerization. The hybrids characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). dielectric behaviors pure PI PI/Al2O3 samples studied...

To improve the reliability of power systems, online cable condition monitoring must be implemented to replace traditional regular outage maintenance. Existing methods have certain limitations. In this article, a novel method based on low-frequency signal injection is proposed monitor insulation conditions online. For method, injected into system via potential transformer (PT) open delta configuration. The conductor voltage and leakage current are detected. interpolating windowed fast Fourier...

Dampness invasion of power cable joints may lead to insulation degradation gradually. Once the joint is severely damp, it rapidly leads breakdown failure for system and finally results in catastrophic accidents. To avoid outages, great significance diagnose with severe dampness defects. Existing methods have certain limitations. In this article, a novel time-frequency domain conversion method determining defects proposed. For method, first located by applying conventional frequency...

For cable accessories, environmental moisture inevitably gradually diffuses into the XLPE–SiR composite interface. The penetrated always causes interface insulation degradation and failure. In this article, to investigate discharge characteristics at insulation, a experimental unit is performed, deterioration when remains dry or becomes damped discussed analyzed. Combined with optical tests, signal scanning electron microscope (SEM) energy-dispersive spectrometer (EDS) are studied. addition,...

The performance of the pantograph–catenary system plays a significant role in determining reliability and safety high-speed train. With an increase train speed, repeated separations between pantograph catenary result increased number arcing events, which exacerbate levels damage on system, leading to frequent accidents. event is complex phenomenon that influenced by various factors, involves interactions electromagnetic, thermal airflow fields. high temperatures generated arc ablation...

The onsite partial discharge (PD) detection of cable insulation is great importance for power system maintenance. To preserve more basic features denoised PD signal, in this paper, a denoising by new class affine projection algorithm (APA) proposed based on the high-order error (HOEP) criterion. We propose least mean absolute third (APLMATA), which exploits HOEP criterion ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math...

The second-order Volterra (SOV) filter is a powerful tool for modeling the nonlinear system. Geman-McClure estimator, whose loss function non-convex and has been proven to be robust efficient optimization criterion learning In this paper, we present SOV filter, named recursive Geman-McClure, which an adaptive algorithm based on estimator. mean stability mean-square (steady-state excess square error (EMSE)) of proposed analyzed in detail. Simulation results support analytical findings show...

This paper presents a novel oscillation wave test system (OWTS) to detect the partial discharge (PD) of mounting defects in power cable insulation. In proposed system, charging capacitor is added circuit topology based on traditional OWTS. The charged desired voltage by high-voltage DC source. After process, sample capacitor. resonant formed capacitor, cable, and reactor create an oscillating decay voltage. With this method, no space charge injected into effect capacitance efficiency...

Silicone grease (SG) is used for lubrication during cable accessory installation and can penetrate into the silicone rubber (SiR), leading to properties deterioration of SiR. In this study, effects SG on breakdown characteristics cross-linked polyethylene (XLPE)–SiR interface are investigated. First, variation XLPE–SiR voltage with coating time experimentally explored. The significantly increases after applied, remains stable times up approximately 144 h then rapidly decreases; minimum lower...

Currently employed features for separating partial discharge (PD) pulse signals are proposed based on captured by a particular sensor. If these used to separate PD other sensors, the distribution of may overlap, making it difficult distinguish different signals. To address challenge poor applicability traditional sensors with amplitude–frequency characteristics in signals, this article proposes time–frequency (T–F) feature extraction method t-distributed stochastic neighbor embedding...

High-speed airflow, which is generated around trains running at a high speed, causes uneven pollutant distribution on insulator surfaces and changes their insulation properties. In this paper, method has been proposed to calculate the residual resistance polluted insulator. Based analysis of flashover model, influence pollution along was discussed. Analysis result showed that voltage would increase when decreased compared conditions with uniformly distributed pollutant, vice versa. It...

Time domain reflectometry (TDR) is an effective method used to detect partial discharge (PD) and localize PD sources on power cables. However, for long-length cables, the attenuation dispersion of signals are significant due propagated distance. The causes a serious reduction pulse amplitude, which makes defects located far away from detector difficult find. appreciable asymmetry in wave form. Thus, localization accuracy reduced. To solve problem cable fault localization, novel signal relay...

This study investigates the microstructural changes of water trees in different stages propagation. It is proposed that within a tree influence its macroscopic Five groups XLPE cable samples with pinhole defects were subjected to an accelerated aging experiment for times. The morphologies and sizes periods observed by optical scanning electron microscopes. microscopic observations show propagation rates can change during stages. In initial stage, rate reach 0.46 μm/hour. However, stagnation...

Partial discharge (PD) detection plays a vital role in on-line condition monitoring of electrical apparatus the power systems. However, noise PD measurements significantly degrades performance algorithms. In this paper, we focus on developing an adaptive filtering technique for denoising problem. Heretofore, there are just few literature reviews addressing based such method. The proposed recursive continuous S-shaped (RCSS) algorithm integrates advantages strategy and function into...