Electric Power ›› 2020, Vol. 53 ›› Issue (3): 119-125.DOI: 10.11930/j.issn.1004-9649.201910051

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Ground Fault Location of Large Generator and External Components

ZHAO Siteng1, GUI Lin1, ZHANG Qixue2, WANG Xiangheng1   

  1. 1. State Key Laboratory of Control and Simulation of Power System and Generation Equipments(Department of Electrical Engineering, Tsinghua University), Beijing 100084, China;
    2. NR Electric Co., Ltd., Nanjing 211102, China
  • Received:2019-10-14 Revised:2019-11-08 Published:2020-03-10
  • Supported by:
    This work is supported by National Natural Science Foundation of China (No.51277103), Science and Technology Project of China General Nuclear Power Group(No.3100077009)

Abstract: A fault location method is proposed to distinguish the ground faults of large generators and their external components. It divides the generator and its external components into four regions:the generator, the high-voltage winding of excitation transformer, the high voltage winding of unit auxiliary transformer, and the remaining external components. According to the zero-sequence direction discrimination principle, the exclusion method is used to check and determine the location of the fault. The key to this location method is to measure the zero-sequence current of generator terminal and high-voltage side of excitation transformer/unit auxiliary transformer. It's necessary to select the TA according to different regions where the fault occurs. The location method was verified by a series of real fault cases, which proved that the method can accurately locate the ground fault of the generator and its external components, with shortened troubleshooting time and in-time power recovery of the generator. The proposed fault location method has the value of popularization and application.

Key words: generator; external components, ground fault location, zero-sequence direction discrimination, exclusion method