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Small-current grounding system single-phase grounding fault distance measurement method based on signal injection method

A single-phase ground fault, small current grounding technology, applied in the direction of the fault location, etc., can solve the problems of numerous branches in the middle of the line, complex fault traveling wave refraction process, high sampling frequency requirements, etc., to ensure accuracy, fast calculation speed, The effect of small amount of computation

Inactive Publication Date: 2011-12-21
SHANDONG ELECTRIC POWER SCHOOL
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Problems solved by technology

The present invention is mainly aimed at the ranging problem of single-phase grounding faults in power transmission systems, and has high requirements for sampling frequency, and is suitable for situations where the length of the line is long and there are no branches in the middle. The catadioptric process of fault traveling waves is complex, and there are certain limitations in using this method in power distribution systems

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  • Small-current grounding system single-phase grounding fault distance measurement method based on signal injection method
  • Small-current grounding system single-phase grounding fault distance measurement method based on signal injection method
  • Small-current grounding system single-phase grounding fault distance measurement method based on signal injection method

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Embodiment Construction

[0035] The present invention will be further described below in conjunction with accompanying drawings and examples.

[0036] 1. Composition of single-phase ground fault location system

[0037] The composition of single-phase ground fault location system in small current grounding system is as follows: image 3 shown. The system includes an injection signal source, a voltage transformer, a zero-sequence current transformer and a single-phase ground fault distance measuring device. The injection signal source can generate a sinusoidal current signal with a frequency different from the natural frequency of the power system, and the amplitude is about 5A. The injection signal source is only connected to the fault phase on the secondary side of the voltage transformer for a short time when a single-phase ground fault occurs. , to inject a detectable signal into the fault line, and stop injecting the signal after the fault disappears; on the one hand, the voltage transformer is us...

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Abstract

The invention relates to a small-current grounding system single-phase grounding fault distance measurement method based on a signal injection method. Under a single-phase grounding fault, a constant-frequency sine current signal is injected through a voltage transformer during secondary lateral fault phase short circuit; the current generates a corresponding voltage drop on a faulted line; relational expressions between injection signal voltage and injection signal current at the head end of the line and the injection signal voltage and the injection signal current on a faulted point can be written by adopting a distribution parameter model of the line based on a long-line equation; relational expressions between the injection signal voltage and the injection signal current on the faulted point and transitional resistance can be also written; the virtual part of the transitional resistance is set to be 0 and the plural equations are solved, so that a fault distance can be obtained. The small-current grounding system single-phase grounding fault distance measurement method based on the signal injection method has the advantages that: due to adoption of an injection signal for distance measurement, influences of a system structure, a running mode and an arc suppression coil can be avoided; due to adoption of the distribution parameter model of the line, an influence of a distribution capacitor can be avoided; therefore, a distance measurement result has higher precision, and the small-current grounding system has high anti-transitional-resistance capability.

Description

technical field [0001] The invention relates to a fault distance measurement method in a power system, in particular to a single-phase ground fault distance measurement method in a small current grounding system based on a signal injection method. Background technique [0002] The 6-35kV power distribution system in my country generally adopts the operation mode of small current grounding. The advantage of this operation mode is that when a single-phase ground fault occurs, because the system line voltage is still symmetrical, it can continue to operate for 2 hours with the fault, so it has a high power supply reliability. The disadvantage of this operation mode is that the characteristics of single-phase ground fault are not obvious, which brings great difficulties to the fault line selection and fault distance measurement. At present, there are many studies on the principle and technology of single-phase ground fault line selection in small current grounding systems, and a...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 荀堂生张嵩宋志明白勇张琳琳丛伟
Owner SHANDONG ELECTRIC POWER SCHOOL
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