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38 results on '"Zhang, Zhousheng"'

1. A partial discharge pattern recognition method based on deep learning and multi-model fusion

Author

WANG Tingting, DING Hao, and ZHANG Zhousheng

Subjects
partial discharge, high voltage switchgear, phase resolved partial discharge (prpd) spectrum, transfer learning, deep residual network (drn), fusion recognition, Applications of electric power, TK4001-4102
Abstract

Partial discharge is closely related to the insulation state of power equipment. Accurate identification of partial discharge types is of great significance to ensure the operation of the power grid. A partial discharge pattern recognition method based on deep learning and multi-model fusion is proposed in this paper. Firstly, four kinds of typical partial discharge defect models in the switchgear are designed and built, and the phase resolved partial discharge (PRPD) spectrum is collected to estalish sample set. Then, a deep residual network based on transfer learning is built to identify partial discharge defects. Finally, the deep residual network (DRN) model is fused with the traditional recognition model by Sugeno fuzzy integral. The experimental results show that the transfer learning model has better update ability and generalization performance than the non-transfer learning model does, and the fusion model has higher recognition accuracy than the single model does. The proposed method can accurately identify the types of partial discharge defects, and has a certain reference value for the operation and maintenance of power equipment.

Published
2023
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2. Partial discharge fault identification of multi-dimensional information sources based on CNN+D-S evidence theory

Author

WANG Lei, ZHANG Lei, NIU Rongze, SUN Qian, LI Fengjun, and ZHANG Zhousheng

Subjects
partial discharge, fault identification, convolutional neural network (cnn), dempster-shafer (d-s) evidence theory, multi-dimensional information sources, information fusion, Applications of electric power, TK4001-4102
Abstract

The partial discharge fault identification method based on the fusion of multi-dimensional information sources can greatly improve the accuracy and fault tolerance in the fault identification of power equipment. In this paper,four typical partial discharge models,namely corona discharge,suspended discharge,floating discharge and air-gap discharge are prepared. The partial discharge signals generated by different discharge models are collected by ultrasonic (Ultra),very-ultra high frequency (V-UHF) and pulse current method (PCM) sensors. Firstly,the deep convolutional neural network (CNN) algorithm is used to train the measurement data of different sensors,and then the Dempster-Shafer (D-S) evidence theory is used to perform fusion calculation on the recognition results of multi-dimensional information sources. Finally,according to the fusion calculation results,the identification conclusion is made. The results show that the fault identification model based on multi-dimensional information sources constructed in this paper has higher accuracy than that based on single information source. When a misjudgment occurs in one of the multi-dimensional information sources,the model can still correctly identify the type of discharge,which indicates that the model has better fault tolerance for the information sources and the recognition effect is good.

Published
2022
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4. Superhumps Behavior during Normal Outbursts in ER UMa: Spectroscopy and Photometry

Author

Zhao, Yinghe, Li, Zongyun, Wu, Xiaoan, Peng, Qiuhe, Zhang, Zhousheng, and Li, Zili

Subjects
Astrophysics
Abstract

We have taken a 4-day spectroscopic observation and have been conducting a 13-day photometric study of the SU UMa-type dwarf nova, ER Ursae Majoris. The mean $K$-amplitude for the emission lines is $54\pm 8$ km s$^{-1}$ and $\gamma$ velocity is 8$\pm 4$ km s$^{-1}$ from our spectroscopic results. A phase shift of 0.22 is also obtained. Our photometric observation confirms superhumps in normal outbursts of ER UMa and reconciles contradictory observational results obtained by different authors. We find that superhumps possibly develop near each normal outburst maximum and fade out before the next outburst maximum. If the observed humps were not late superhumps but ordinary superhumps, much more theoretical works should be done to explain the new phenomena., Comment: 16 pages, 10 figures, accepted for publication in PASJ

Published
2006
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5. Superhumps in a Peculiar SU UMa-Type Dwarf Nova ER Ursae Majoris

Author

Gao, Weihong, Li, Zongyun, Wu, Xiaoan, Zhang, Zhousheng, and Li, Yulan

Subjects
Astrophysics
Abstract

We report the photometry of a peculiar SU UMa-type dwarf nova - ER UMa for ten nights during 1998 December and 1999 March covering a complete rise to the supermaximum and a normal outburst cycle. Superhumps have been found during the rise to the superoutburst. A negative superhump appeared in Dec.22 light curve, while the superhump on the next night became positive and had large amplitude and distinct waveform from that of the previous night. In the normal outburst we captured, superhumps with larger or smaller amplitudes seem to always exist, although it is not necessarily true for every normal outburst. These results show great resemblance with V1159 Ori (Patterson et al. 1995). It is more likely that superhumps occasionally exist at essentially all phases of the eruption cycles of ER UMa stars, which should be considered in modeling., Comment: 4 pages, 5 figures, Accepted by ApJ Letters

Published
1999
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6. Effect of Electrostatic Probe Online Measurement on Surface Charge Distribution for HVDC GIL

Author

Zhang, Lei, Yu, Di, Tang, Deyue, and Zhang, Zhousheng

Abstract

In this article, a 3-D simulation model of surface charge accumulation for 200-kV dc gas-insulated transmission line (GIL) basin insulator is constructed. Meanwhile, the whole process of electrostatic probe online measurement is established, and the motion process of electrostatic probe is simulated by the dynamic grid module in finite element software. The key factors in electrostatic probe online measurement are considered comprehensively, including the probe initial position, central conductor potential, probe measuring time, and measuring position. The variation of surface charge density and surface normal electric field after online measurement is calculated and analyzed. The results show that the surface charge density near the probe center is obviously affected after online measurement, while the surface charge density in the region far away from the probe is less affected. When the distance ${D}$ between the probe initial position and the insulator surface is less than 10 mm, the polarity of the surface charge at the measured point will be reversed. When ${D}$ reaches 100 mm, the change rate of the surface charge density is less than 5%. In addition, with the increase of the central conductor potential and probe measuring time, the surface charge density at the measured point decreases more after online measurement. When the probe measures at the same position for more than 3 min, the surface charge density decreased by more than 30%. Moreover, the closer the probe is to the central conductor, the more the surface charge density is reduced after online measurement. This study can provide reference for the online measurement technology of dc GIL insulator’s surface charge density.

Published
2024
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23. Gas–solid interface charge tailoring techniques: what we grasped and where to go.

Author

Zhang, Zhousheng, Wang, Zheming, Teyssedre, Gilbert, Shahsavarian, Tohid, Baferani, Mohamadreza Arab, Chen, Geng, Lin, Chuanjie, Zhang, Bo, Riechert, Uwe, Lei, Zhipeng, Cao, Yang, and Li, Chuanyang

Subjects
*GAS-solid interfaces, *ELECTRIC insulators & insulation, *ELECTRIC fields, *INDUSTRIAL applications
Abstract

Charging of insulators modifies local electric field distribution and increases potential threat to the safety of the gas insulated equipment. In this paper, surface charge tailoring techniques are classified and reviewed by introducing a Dam-flood model. Technical solutions of different charge tailoring methods are compared and discussed. The outlook of potential solutions to suppress charge accumulation is recommended and discussed based on industrial consideration. This paper serves as a guide handbook for engineers and researchers into the study of charge tailoring methods. Meanwhile, we hope that the content of this paper could shed some lights upon charge-free insulators to promote the industrial application of HVDC GIL/GIS. [ABSTRACT FROM AUTHOR]

Published
2021
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37. Synthesis of fractal signals with wavelet bases.

Author

Liu Feng, Liu Guizhong, and Zhang Zhousheng

Subjects
*FRACTALS, *WAVELETS (Mathematics)
Abstract

Examines the synthesis of fractal signals with wavelet bases. Formula for time-average spectrum; Analysis of wavelets; Dependencies among wavelet coefficients.

Published
2001

38. Surface charging on HVDC spacers considering time-varying effect of temperature and electric fields

Author

Zhousheng Zhang, Wu Yan, Tao Han, Zhipeng Lei, Chuanyang Li, Davide Fabiani, and Yan Wu, Li Chuanyang, Lei Zhipeng, Han Tao, Zhang Zhousheng, Fabiani, Davide

Subjects
010302 applied physics, Materials science, Condensed matter physics, Charge density, Conductivity, 01 natural sciences, Ion, Temperature gradient, Electric field, Phase (matter), electric field,GIL,HVDC spacer, surface charge accumulation, temperature, 0103 physical sciences, Heat transfer, Surface charge, Electrical and Electronic Engineering
Abstract

The dynamic behavior of surface charging on spacers in DC-GILs can be influenced by multi-factors including the non-uniform distributed electric field as well as the time-varying temperature gradient. In this paper, the time-varying effect of surface charging phenomenon on spacers is studied and a time-varying mathematical model is established, based on the influence of temperature and electric field on the ion mobility at the gas phase and the bulk conductivity in the solid phase. The results verify that the bulk conductivity can be greatly influenced by temperature, which leads to an increase in the surface charge density on the spacer. This allows the surface charge accumulation to stabilize more quickly. However, the ion mobility from the gas phase is less affected by temperature. When the non-uniform distributed electric field changes from 1.3 to 6.4 kV/mm, ion mobility is less influenced and the surface charge density on the spacer varies slightly. In this case, the effects of the non-uniformly distributed electric field in surface charge density variation is much smaller and can be ignored.

Published
2019

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