Partial discharge (PD) detection and localization is one of the most effective methods in gas-insulated transmission lines (GIL) insulation fault diagnosis, which important to early troubleshooting safe operation. Compared with widely used ultrahigh frequency (UHF) acoustic PD methods, method based on optical signals has good resistance electromagnetic interference. However, current comes several shortcomings: narrow range, requiring field experiments accumulate data, installing a large...

The electroreduction of carbon dioxide (CO2) to a liquid product is viable method for establishing an artificial cycle. Unfortunately, most electrocatalysts' low efficiency and instability prevent them from being used in practical applications. In the current study, we developed ultrasmall Cu nanocrystals embedded nitrogen-doped nanosheets (Cu/NC-NSs) selective CO2 by adjusting potential. Cu/NC-NSs had 43.7 63.5% Faradaic efficiencies synthesis ethanol formate with applied potentials -0.37...

To design high-sensitivity sensors is one of the critical issues to be solved for ultra-high-frequency (UHF) partial discharge (PD) detection in substations. Commonly-used UHF usually use ultra-wideband antennas frequency bands ranging from 300 MHz 1.5 GHz. avoid interference bands, such as signals generated mobile phones, a new multi-band sensor proposed based on loop antenna theory and meandering technique, which reduces size, provides high sensitivity exhibits omnidirectional performance....

Partial discharge (PD) is one of the main causes rendering deterioration insulation state in gas-insulated transmission line (GIL). Accurate and timely localization PD source essential to ensure safe stable operation GIL. At present, optical detection technology shows advantages terms high sensitivity strong anti-interference performance. Therefore, an method based on simulation fingerprint database proposed. The introduction conquers difficulty obtaining a field experiments. This constructs...

Partial discharge (PD) detection has been widely applied to high voltage cable systems for several decades. In this paper, three kinds of insulation defects in XLPE cables are designed and tested at step-wise DC voltage. The PD developing progress each defect is divided into two stages based on the severity degree PDs. Based compressed sensing (CS) theory, a novel method used recognizing patterns proposed. Firstly, both statistical features repetition rate norm characteristics time domain...

A new method to extract the features of direct current (DC) cross linked polyethylene (XLPE) cable partial discharge (PD) image based on non-subsampled contourlet transform (NSCT) is proposed in this paper. Four types PD images are obtained from artificially designed insulation defects. The include Shannon entropy, Renyi Euclidean distance, and Mahalanobis distance optimized subband coefficients by NSCT. selected immune algorithm affinity propagation clustering method. back propagating...

We theoretically investigate the effect of a zero-area pulse on excitations interacting Rydberg atoms. The unexpected breakdown dipole blockade occurs in strong regime, which results from nonadiabatic character phase-jump with also check modulation final probability double and find that switching time should be short enough to observe blockade.

Partial discharge (PD) is an important phenomenon that reflects the insulation condition of electrical equipment. In order to protect safety power grids, it significance diagnose type defects inside equipment accurately and early through PD pattern recognition. this article, phase resolved pulse sequence (PRPS) graphs in 3D were constructed by data gas-insulated switchgear (GIS) acquired, then histogram oriented gradient (HOG) features extracted directly from PRPS graphs, finally attribute...

Realization of an electrical aircraft demands a low-weight electric distribution and propulsion system. The use high voltage power electronics operated at switching frequencies is essential to achieve this objective. However, printed circuit boards (PCBs) in electrified are harsh working environment, which can make PCBs more susceptible generate partial discharges (PDs). current PD detection technology has poor immunity the electromagnetic interference acoustic operating environment...

This paper presents a new method to improve the insulation defect classification rate of DC cross linked polyethylene (XLPE) cables. A partial discharge (PD) test platform is built in laboratory and four cable models are designed. The PD signal collected by high frequency current transducer (HFCT) q-At-n image constructed. contourlet transform performed on image, Tsallis entropy feature each subband coefficient calculated. error-correcting output codes (ECOC) classifier optimized adaptive...

Optical partial discharge (PD) detection is an efficient means of diagnosing the insulation status power equipment. C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> F xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> N/CO xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas mixture a very potential environmentally-friendly SF xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> substitute gas, and its PD optical characteristics need to...

When partial discharge (PD) occurs in the gas-insulated transmission line (GIL), accompanied by occurrence of sound, light, electricity and thermal phenomena, propagation characteristics optical PD signal are basis for arrangement sensors source location. To study characteristics, simulation models GIL established. The total irradiance map (TIM) average value relative (AVRI) on each detection plane observed under different positions, distances L-shaped angles. results indicate that 1) when...

The environmentally friendly gas C4F7N has been considered a potential replacement for SF6 due to its excellent insulation. At present, research on and mixture mainly focuses insulation performance, but few people study surface discharge mechanism variation law. In order the characteristics of C4F7N/CO2 mixture, fluid model was established simulated by COMSOL, which used streamers during discharge, fit expression maximum photon flux, analyze influence voltage dielectric constant insulator...

In recent years, the environmentally friendly gas, C4F7N, has been recognized as a potential SF6 alternative gas due to its excellent insulation. To study streamer discharge characteristics of different electrode shapes in fluid model was established by COMSOL, and simulations were performed. Streamer function varying analyzed, variation law electric field intensity photon flux obtained, which serves theoretical basis for optical detection reliable diagnosis partial discharge. Simulation...

This article is devoted to simulating the generation and propagation of EM waves caused by partial discharge (PD) inside a void defect. Although many researchers have focused on micro process, few are studying its impact ultrahigh-frequency (UHF) signal generation. For simplicity, several studies replace PD with predetermined Gaussian source. proposes an accurate pulsed current model for UHF which further links waveform source condition. At level, penetration defects, whose steep rising edge...

Sensitive signal perception and accurate fault diagnosis are key to partial discharge (PD) optical detection. To improve the effectiveness of PD detection diagnosis, this paper uses sensing technology based on a light guide rod (LGR) measure typical PDs in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> . The characteristics signals analyzed method for detected by LGR is proposed. An electrical experimental platform built, four...

Hydraulic spring mechanism is widely used in high pressure, ultra-high pressure switch field. During the operation and maintenance of HMB-8 circuit breaker hydraulic mechanism, will be frequently pressed. This paper studies pressed leaked fault UHV equipment. Through theoretical analysis experimental verification, failure including system characteristics seal revealed. The accuracy study verified by setting up a test model conducting field tests. provides an important reference for stable

Abstract Partial discharge identification is of great significance in monitoring power equipment. Although substantial work has been done partial pattern recognition, most studies have performed noise‐free environments. To improve the accuracy this paper introduces a image feature extraction method based on upright speeded‐up robust features. Each group phase‐resolved pulse sequence data converted into grayscale images to construct sample library defects. Upright features used extract...

With the widespread application of power electronic switching technology, equipment is facing new electrical stresses brought about by multilevel staircase voltages during testing and operation. Therefore, partial discharge (PD) behavior five typical defects in under waveform needs to be investigated. This article mainly analyses phase-resolved PD (PRPD) pattern pulse repetition rate (PRR) sinusoidal voltage with different number levels. Also, step responses are By analyzing reasons behind...

In this paper, in order to represent three kinds of typical partial discharge respectively happened dielectric, out dielectric and surface five models, which included needle plate, needle, plate air void, were designed manufactured with aluminum. Based on the an experiment system ultra high frequency detection was comprised non-partial transformer, 2.5 GHz bandwidth oscilloscope, broad band amplifier developed double helical antenna. Afterwards, experiments carried air, method recommended...

Feature extraction of partial discharge (PD) signals is a key step in the pattern recognition and fault diagnosis power equipment. The theory singular spectral entropy analysis (SSEA) introduced order to study complexity irregularity degree PD signals, but it cannot reflect inherent nonlinear characteristics. fourth‐order cumulant used instead covariance matrix SSEA, ensemble empirical mode decomposition (EEMD) method applied realize multiple scales. proposed multi‐scale high‐order (M‐HSSEA)...

Partial discharge detection is important for identifying insulation defects of power cables, and the extraction effective characteristic parameters emphasis study. In this paper, a feature method based on 2 Dimensions Littlewood - Pale empirical wavelet transform (2D-LPEWT) proposed to realize accurate identification different types in cable discharge. By constructing cable-insulated partial platform, three-dimensional spectrum four typical defect models was decomposed by 2D-LPEWT. And then...

A Two-dimensional simulation of the atmospheric pressure needle-plane streamer discharge is presented in this paper. The model consists three continuity equations for electrons and ions coupled with Poisson’s equation. Photon flux was estimated by impact ionization reactions. distributions electric field photon from primary to secondary are discussed, where velocity 2.16×105 m/s radius filament varied 0.012 cm 0.02 cm. variation similar that field. When close cathode, exponentially increased...