Method and device for identifying faults of ground capacitor of generator terminal circuit breaker

A machine-end circuit breaker and fault identification technology, which is applied in the direction of measuring devices, instruments, and measuring electronics, can solve the problems of long time consumption and wide search range, and achieve the effect of reducing the scope of troubleshooting and improving the efficiency of troubleshooting

Active Publication Date: 2018-09-28
NR ELECTRIC CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But at present, there is no method that can reliably identify the fault of the ground capacitor of the generator end circuit breaker. When the user searches for the fault point, the search range is wide and it takes a lot of time. Therefore, it is necessary to study a method that can correctly identify the generator. Method and device for failure of terminal circuit breaker to ground capacitor

Method used

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  • Method and device for identifying faults of ground capacitor of generator terminal circuit breaker
  • Method and device for identifying faults of ground capacitor of generator terminal circuit breaker
  • Method and device for identifying faults of ground capacitor of generator terminal circuit breaker

Examples

Experimental program
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Effect test

Embodiment 1

[0032] The fault identification method of the ground capacitor of the generator machine end circuit breaker, including:

[0033] S1, collecting the voltage on the stator side of the generator terminal;

[0034] S2, according to the voltage collection results of S1, set the phase with the lowest voltage to ground as the fault phase, and calculate the fault phase to ground voltage, stator side voltage, generator stator to ground zero-sequence voltage, and the electromotive force of the fault phase;

[0035] S3, set the phase difference threshold range; according to the calculation results of S2, compare the phase relationship between the fault phase electromotive force and the stator-to-ground zero-sequence voltage: if the phase difference of the fault-phase electromotive force ahead of the stator-to-ground zero-sequence voltage is within the phase difference threshold range , it is judged that the ground capacitor of the machine-side circuit breaker is faulty, otherwise it is a...

Embodiment 2

[0043] Different from Embodiment 1, in S2 of this embodiment, the zero-sequence voltage of the generator stator to ground is the zero-sequence voltage generated by the generator terminal PT.

[0044] Generator terminal PT self-generated zero-sequence voltage for;

[0045]

[0046] in, is the phase-to-ground voltage of generator terminal A, is the phase-to-ground voltage of generator terminal B, It is the phase-to-ground voltage of generator terminal C.

[0047] References for the judgment and identification basis of Embodiment 1 and Embodiment 2 figure 1 . Stator ground zero sequence voltage Located on the horizontal axis, when the generator stator is single-phase grounded and the primary winding of the machine terminal PT is short-circuited, the fault phase electromotive force is located in the third quadrant, that is, the phase difference between the fault phase electromotive force and the stator-to-ground zero-sequence voltage is 180-270 degrees ; When the gr...

Embodiment 3

[0049] The fault identification device for the ground capacitor of the generator machine end circuit breaker, including:

[0050] The sampling module collects the voltage on the stator side of the generator terminal;

[0051] The calculation module, according to the voltage collection results of the stator side of the generator terminal, sets the phase with the lowest voltage to ground as the fault phase, and calculates the fault phase to ground voltage, the voltage on the stator side, the zero-sequence voltage of the generator stator to ground, and the electromotive force of the fault phase;

[0052]The fault identification module sets the phase difference threshold range; according to the calculation result of S2, compares the phase relationship between the fault phase electromotive force and the stator-to-ground zero-sequence voltage: if the fault phase electromotive force leads the phase difference of the stator-to-ground zero-sequence voltage within the phase difference th...

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Abstract

The invention discloses a method and device for identifying faults of a ground capacitor of a generator terminal circuit breaker. The method includes the steps that the voltage at the stator side of agenerator terminal is acquired; the minimum phase of the ground voltage is set as a fault phase according to a voltage acquisition result, and the voltage-to-earth of the fault phase, the voltage atthe stator side, the zero-sequence voltage-to-earth of a generator stator and the electromotive force of the fault phase are calculated; a phase difference threshold range is set, and the phase relation between the electromotive force of the fault phase and the zero-sequence voltage-to-earth of the stator is compared; if the phase difference between the electromotive force of the fault phase and the zero-sequence voltage-to-earth of the stator is in the phase difference threshold range, it is judged that the ground capacitor of the generator terminal circuit breaker breaks down, and otherwise,it is judged that the ground capacitor of the generator terminal circuit breaker does not break down. By means of the method and device, when ground faults happens to the ground capacitor of the generator terminal circuit breaker, the types of the faults can be reliably identified, the troubleshooting range is narrowed for users, and the troubleshooting efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method and a device for identifying faults of a ground capacitor of a generator machine end circuit breaker. Background technique [0002] Large-scale generators generally adopt the method of changing the neutral point to ground through the ground, and meet the requirements of R N ≤X C , where R N The resistance value converted to the primary resistance for grounding and changing the secondary load resistance, X C is the capacitive reactance of the generator stator winding to ground. For a unit that meets the above conditions, regardless of single-phase grounding of the stator, inter-turn short circuit of the PT primary winding at the machine end, or ground capacitor failure of the machine end circuit breaker, the stator winding fault relative to ground voltage is the lowest. But at present, there is no method that can reliably identify the fa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
CPCG01R31/00
Inventor 陈俊钟守平王光陈佳胜张琦雪
Owner NR ELECTRIC CO LTD
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