Huicun Zhao, Yu Gao, Wenqu Wang, X. Yuan, Huan Wang
{"title":"Regulation of Surface Charge Accumulation on Epoxy Insulator by Flexible Coating under DC Voltage","authors":"Huicun Zhao, Yu Gao, Wenqu Wang, X. Yuan, Huan Wang","doi":"10.1109/ICEMPE51623.2021.9509007","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509007","url":null,"abstract":"Surface charge accumulation on alumina/epoxy insulator affects the safe and reliable operation of the highvoltage direct-current (HVDC) gas insulated transmission line (GIL) and gas insulated switchgear (GIS). In this paper, a flexible coating strategy was proposed to suppress the charge accumulation on the insulator, so as to optimize the electric field distribution. The insulator with multi-arc surface profile and a coaxial electrode system were designed, then surface coatings with various conductivities were deposited on the designated areas of the epoxy insulator by brushing method. The effects of flexible coating on the charge accumulation behavior of the insulator under −15, −20 and −25 kV DC voltages were studied by a kelvin type probe. The results showed that when the metallic wire was adhered on high voltage electrode, the positive charges were accumulated on the nonplanar region in the form of speckles, and the flexible coating could significantly inhibit the charge accumulation on the insulator.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89952685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geqi Li, Ke Wang, Shuqi Zhang, F. Yang, Peng Li, Jinzhong Li, Gang Li, Xueli Liu
{"title":"Research on A Transition Circuit of Vacuum On-Load Tap-Changer","authors":"Geqi Li, Ke Wang, Shuqi Zhang, F. Yang, Peng Li, Jinzhong Li, Gang Li, Xueli Liu","doi":"10.1109/ICEMPE51623.2021.9509054","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509054","url":null,"abstract":"As an important component of transformers and converter transformers, vacuum on-load tap-changers directly affect the reliability of power grid operation. In order to improve the reliability of the tap-changer, it is necessary to study the transition circuit of the tap-changer and its operation method in order to improve it. This paper analyzes two kinds of transition circuits of vacuum on-load tap-changers and their operation methods, and analyzes the breaking tasks of each contact in the transition circuit. It is found that the two topologies have an imbalance in the breaking capacity of the two internal vacuum tubes. This paper proposes a type of vacuum on-load tap-changer topology, which adds a vacuum tube and a transition resistance. At the same time, an operation method is proposed, which changes the vacuum tube with heavy switching task into two vacuum tubes that operate alternately in the adjacent switching, and changes one transition resistance into two transition resistances that work alternately. It reduces the burden of a single auxiliary vacuum tube, balances the contact ablation of each vacuum tube under long-term operation, and reduces the temperature rise of the transition resistance, which improves reliability of the tap-changer.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"42 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86590432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Yin, F. D. da Silva, C. Bak, Hanchi Zhang, Qian Wang, H. Skouboe
{"title":"Electric Field Computation and Optimization for A 400 kV Y-shaped Composite Cross-arm","authors":"K. Yin, F. D. da Silva, C. Bak, Hanchi Zhang, Qian Wang, H. Skouboe","doi":"10.1109/ICEMPE51623.2021.9509173","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509173","url":null,"abstract":"A new proposed Y-shaped composite pylon has a potential to become the next new generation $2times 400text{kV}$ overhead line transmission tower. However, according to previous work, the electric field magnitudes inside the hollow cross-arm tube exceeds the onset electric field strength of corona, which does not meet the requirements of insulation. In this paper, an electrostatic field model is established by using finite element method analysis. Aiming to previous existing issues, we propose using low density polyethylene (LDPE) as filling material to fill the cross-arm. Meanwhile, the clamps structure is redesigned. Then, the electric field distribution results along the surface of the cross-arm and around the clamps are presented. Furthermore, through the shape optimization, the electric field distribution of clamps and sheds meets the design criteria. Finally, taking advantages of the insulation margin, the conductor enclosure is removed and the height of the clamp is decreased. The final clamp structure meets the insulation requirement.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"2 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79530109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongsheng Zhan, Chuanhui Cheng, R. Zhuo, M. Fu, Zhiming Huang, Yan Luo
{"title":"A Study on the Non-linearity of Dielectric Response in Time Domain of Oil-paper Insulation","authors":"Hongsheng Zhan, Chuanhui Cheng, R. Zhuo, M. Fu, Zhiming Huang, Yan Luo","doi":"10.1109/ICEMPE51623.2021.9509118","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509118","url":null,"abstract":"Up to date, an increasing interest arises on the dielectric response measurement in time and frequency domain to assess the condition of the oil and paper insulations of electrical equipment. The polarization and depolarization current (PDC) is widely accepted as a simple but effective technique dielectric response in time domain, which is based on the linear dielectric system. In the presented paper, the PDC technique is applied to study the non-linearity of dielectric response in time domain of oil-paper insulations. Two sample configurations, i.e., a layer of oil immersed paper sample and two layers of an oil gap and oil immersed paper layer, are used to study the effect of structure on the non-linearity. The nonlinearity of dielectric response is evaluated under various voltages and various sample configurations. It is found that a non-linearity of dielectric response in time domain of multilayer of oil and paper occurs in extremely low field region, much lower than that of a single layer of oil immersed paper. Charge carrier's motions in the oil gap and interface polarization shall play a critical in the non-linearity.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"64 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88395330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sen Qian, Xiaojing Zhang, Chuan Chen, Hongkang Wang, Jinghong Guo, Yang Xu
{"title":"Ageing Evaluation of the Distribution Transformer under Varying Load due to Electric Vehicle Charging","authors":"Sen Qian, Xiaojing Zhang, Chuan Chen, Hongkang Wang, Jinghong Guo, Yang Xu","doi":"10.1109/ICEMPE51623.2021.9509233","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509233","url":null,"abstract":"Electric vehicles are expected to offer many benefits over conventional vehicles, such as reduction of carbon emission and fuel costs. However, the adoption of electric vehicles would bring great challenges to the distribution transformer, as their charging behavior would make the transformer operate under the varying load and therefore submit to overload risk. Hence, the insulation aging which shortens the transformer lifetime would be accelerated. In this research, we study the impacts of electric vehicle charging on the aging of the distribution transformer with conventional and high-temperature insulations. The number of households, base load and charging habits of a district in Jiaxing city are collected, and then a Monte Carlo simulation model is proposed to evaluate the additional load demand due to the electric vehicle charging. Furthermore, the simulated load demand is input to a model, which is modified based on the algorithm stipulated in IEEE C57.91, to calculate the thermal rise and the aging of the distribution transformer. The results imply that the electric vehicle charging would exacerbate the swing of the load demand. Particularly, the lifetime of the conventional distribution transformer would be significantly reduced. In comparison, the high-temperature insulation could mitigate the negative impacts of the electric vehicle charging on the transformer ageing.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"8 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88788273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Research on high voltage capacitor partial discharge detection with portable oscillating wave circuit","authors":"Lingying Chen, Guangke Xu, Panfeng Shang","doi":"10.1109/ICEMPE51623.2021.9509209","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509209","url":null,"abstract":"At present, the partial discharge(PD) detection of high voltage power capacitor usually employs a resonant circuit which requires a very bulky reactor, and a PD detector with ultrasonic sensors. One of the problems with this approach is difficult experimental setup. Another is the limitation of PD signal analyze and get further valuable information, due to the properties of ultrasonic signal itself. This paper reports on a new user-friendly and effective way to carry out PD test of HV power capacitor. This system contains a supply module, a specially made sampling impedance and a PD pulse collector. The supply module, consists of high voltage DC power generator, protection resistance, damping resistance, semiconductor switch, which is integrated designed, characterized by small size, light weight, and low power consumption. The specially made sampling impedance which is employed to obtain PD signals could be applied to the detection of capacitor samples with different capacity, and the impedance can be directly connected to the end of the capacitor without the influence of large current signal. And the PD pulse collector is different from PD detectors under stable voltage, which needs to grasp the PD signal accurately in several cycles of the test loop oscillation, and the signal acquisition is required to be continuous. Compared with the previous approach, the oscillating wave circuit with specially made impedance reported in this paper, showed much more portability for large power capacitors PD detection, and the results provided chances for time and frequency domain spectrum analysis, which could be helpful to identify the PD type of HV power capacitors.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"5 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73105199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peng Li, Mingxin Dong, Gang Li, Shuqi Zhang, Ke Wang, Jinzhong Li
{"title":"Calculation of Excitation Current and Loss of 110kV Three-phase Transformer under DC Bias","authors":"Peng Li, Mingxin Dong, Gang Li, Shuqi Zhang, Ke Wang, Jinzhong Li","doi":"10.1109/ICEMPE51623.2021.9509157","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509157","url":null,"abstract":"Power transformers are the key equipment in the power grid. Direct current (DC) bias of transformer, which are often derived from solar storms, high voltage DC (HVDC) transmission and subway lines, poses a serious threat to the stable operation of the power system. To study the mechanism of the loss increase under DC bias, a magnetic-circuit coupling model was designed based on duality principle and applied to calculation of the excitation current of 110kV three-phase three-leg under different DC current injection. Subsequently, a three-dimensional (3D) simulation model of the 110kV transformer was built in which the losses of different parts under various DC currents were calculated. It is observed that the average value of the three-phase excitation current peaks increased approximately linearly with the increase of DC current. Different increasing trends appear in the loss of different components consisting of clamps, pull plates and oil tanks, which means that different temperature rises can appear in the above components probably causing local overheating. Based on the obtained results, it is necessary to distinguish the losses of different parts and further evaluate the limit of the transformer tolerance to DC bias current.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"20 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73974525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yucheng Zhang, Z. Hao, Hai-Yue Yang, Boyu Li, Shaoyong Yao, R. Yin
{"title":"Mechanism of Gas Movement and Convergence in Oil-immersed Transformer","authors":"Yucheng Zhang, Z. Hao, Hai-Yue Yang, Boyu Li, Shaoyong Yao, R. Yin","doi":"10.1109/ICEMPE51623.2021.9509192","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509192","url":null,"abstract":"As a transformer main protection, light gas protection responds to transformer failure solely based on the gas volume within its collection chamber. Such single protection criterion failed to reflect the actual transformer working condition accurately, which have led to protection malfunction or refusal-operation and caused several transformer explosions so far. In order to analyze the mechanism of gas movement and convergence within oil-immersed transformer, an experimental tank with physical structure resembling that of a power transformer is set up, corresponding two-phase flow model is established in ANSYS, simulations of different developing stages throughout the oil-paper insulation breakdown process is conducted. Experiments confirm with simulation results, which state that as fault develops, gas transferred from where the fault occurs, to the upper surface of different structures within the tank; gas generation rate increases throughout time, during which gas exhibits different moving patterns and undergo morphological changes. The purpose of this study is to clarify the gas behavior within oil-immersed transformer based on the moving and converging pattern of gas generated by transformer internal fault.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"41 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73741762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kong Jiaying, Zhang Yewen, Zebin Cao, Zheng Feihu, T. Qian
{"title":"Noise analysis and device improvement of composite probe for space charge measuring based on PIPWP method","authors":"Kong Jiaying, Zhang Yewen, Zebin Cao, Zheng Feihu, T. Qian","doi":"10.1109/ICEMPE51623.2021.9509180","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509180","url":null,"abstract":"In order to find the source of noise signal which always appears in the process when using the composite probe, this paper proposes a hypothesis which is based on experimental facts. Through the establishing a pressure wave transmission model and analyzing the equivalent circuit, the correctness of the assumption is verified from the perspective of time and amplitude. Finally, the noise signal is moved forward by modifying the structure of the composite probe.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"81 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73022865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Zhang, Xueqin Zhang, Bo Wang, Qing Du, Yujun Guo, Guangning Wu
{"title":"Study on the Arc Characteristics of Insulator Creeping Discharge under High Velocity Air","authors":"G. Zhang, Xueqin Zhang, Bo Wang, Qing Du, Yujun Guo, Guangning Wu","doi":"10.1109/ICEMPE51623.2021.9509203","DOIUrl":"https://doi.org/10.1109/ICEMPE51623.2021.9509203","url":null,"abstract":"The roof insulator of high-speed trains is the key equipment for high-voltage isolation and mechanical support of pantographs, and its good insulation service performance is the basic condition to ensure the safe operation of trains. The roof insulation system is the weak link of train insulation performance, therefore, it is necessary to conduct relevant research on the arcing characteristics of roof insulators along the surface discharge under high speed airflow, and to investigate the discharge characteristics of insulators along the surface of high speed trains, which is an important problem that needs to be solved in the process of high speed railroad safety operation. In this paper, surface discharge tests were conducted on insulators using wind tunnel system to obtain the motion characteristics of insulator surface discharge photons at different airflow velocities and the surface discharge arcs of insulators at different airflow velocities. It is found that the surface discharge arc position of the insulator moves significantly to the side and back with the increase of airflow speed; the UV photon and corona discharge area of the insulator move backward with the increase of airflow speed, revealing the surface arc motion characteristics of the insulator under high speed airflow. Therefore, the research of this paper provides important theoretical support for the insulation design and insulation fit of high-speed trains, which ensures the safe and stable operation of high-speed trains.","PeriodicalId":7083,"journal":{"name":"2021 International Conference on Electrical Materials and Power Equipment (ICEMPE)","volume":"24 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2021-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72786166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}