Comprehensive detection method for high resistance ground faults of electric power system

A high-resistance ground fault, comprehensive detection technology, applied in the direction of fault location, measuring electricity, measuring devices, etc.

Active Publication Date: 2014-01-22
STATE GRID CORP OF CHINA +1
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Problems solved by technology

However, the high-resistance ground fault that is difficult to detect by traditional protection methods is a difficult problem in this type of system.

Method used

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  • Comprehensive detection method for high resistance ground faults of electric power system
  • Comprehensive detection method for high resistance ground faults of electric power system
  • Comprehensive detection method for high resistance ground faults of electric power system

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Embodiment Construction

[0088] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0089] Intermittent high-impedance ground fault detection is mainly used to identify faults that cannot be detected due to the intermittent occurrence of faults, and because most of the intermittent faults contain a large amount of high-frequency content, the distributed capacitance will also cause relatively high ground faults on healthy lines. If there is a large disturbance, it is necessary to identify the fault line; therefore, the focus of intermittent high-resistance ground fault detection is to use the "transient direction" to identify the fault line.

[0090] In this technical solution, the unified traveling wave theory based on instantaneous reactive power is taken as the core of the direction detection method, and the power direction is the basis of the direction detection.

[0091] figure 1 In , a schematic diagram of the typical power flow ...

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Abstract

The invention provides a comprehensive detection method for high resistance ground faults of an electric power system and belongs to the field of emergency protective circuit devices. The detection method comprises two parts of utilizing a transient state direction to recognize faulty lines and utilizing intermittent detection to detect intermittent faults; fault component current and voltage are calculated based on voltage and current waveforms before fault startup and a fault direction is obtained by utilizing the fault component voltage and current waveforms to calculate transient idle work; with regard to forward pulse counting, a pulse count is compared with a pre-set threshold value to judge a fault when detection time is cut off so as to more sensitively detect intermittent high resistance ground faults and cut off the fault lines in time; and furthermore, the sensitivity of a power supplying line protective device is improved so as to be good for improving the continuous and stable operation of a whole middle-voltage power distribution system and ensure the safety performance of a whole power supply system. The comprehensive detection method can be widely applied to the fields of high resistance ground fault detection and relay protection of the middle-voltage power distribution system with an effectively-grounded neutral point.

Description

technical field [0001] The invention belongs to the field of emergency protection circuit devices, in particular to a detection / protection method for high-resistance grounding faults in cable or line systems. Background technique [0002] In my country's power system, the AC voltage level with a nominal voltage of 1kV and below is defined as low voltage, the AC voltage level with a nominal voltage of 1kV and below 330kV is defined as high voltage, and the AC voltage level with a nominal voltage of 330kV and above The voltage level is defined as ultra-high voltage, and the AC voltage level with a nominal voltage of 1000kV and above is defined as ultra-high voltage; the standard document of the Institute of Electrical and Electronic Engineers (IEEE) defines the voltage from 2.4kV to 69kV The level is called medium voltage; in the normative documents of my country's State Grid Corporation (State Grid), the voltage level from 1kV to 20kV is called medium voltage. [0003] The gro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00G01R31/08G01R31/02
Inventor 林辉殷迪清童俊金文东金亮陆煜
Owner STATE GRID CORP OF CHINA
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