Distribution network fault line selection method using form peak valley detection

A technology of distribution network fault and line selection method, applied in the direction of fault location, etc., can solve the problems of high sampling rate, synchronous sampling frequency and acquisition and recording hardware requirements, and high system electromagnetic compatibility requirements

Active Publication Date: 2011-07-20
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

[0003] The purpose of the present invention is to overcome the deficiency that the existing distribution network line selection method requires a high sampling rate, and proposes a method for realizing distribution network fault line selection by using morphological peak and valley detection, which properly solves the problem of synchronous sampling frequency and The hardware requirements for collecting and recording are high and the requirements for electromagnetic compatibility of the system are high

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  • Distribution network fault line selection method using form peak valley detection
  • Distribution network fault line selection method using form peak valley detection
  • Distribution network fault line selection method using form peak valley detection

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Embodiment Construction

[0053] Simulation model such as figure 1 As shown, set the overhead line L 1 A single-phase ground fault occurs at a distance of 10km from the busbar, and the fault time t f =25ms, the transition resistance is 20Ω, the fault closing angle is 90°, the time window length is 10ms, and the sampling frequency is 10kHz.

[0054] (1) After a single-phase ground fault occurs in the distribution network, when the bus zero-sequence voltage is 15% higher than the rated phase voltage, the starting element starts immediately. According to the formula:

[0055] i j0 = i jA + i jB + i jC j=1,2,...6 (1)

[0056] Obtain the zero-sequence current of each line, the zero-sequence current waveform is as follows figure 2 shown.

[0057] (2) The sampling frequency is 10kHz, the sampling sequence length is 100, and the zero-sequence current of each line is calculated i j0 the envelope of . The method of calculating the envelope is as follows:

[0058] 1. Find out i j0 Al...

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Abstract

The invention provides a distribution network fault line selection method using form peak valley detection, comprising the following steps of: when a distribution network line occurs faults, starting a line selection device, according to the three-phase current of each line measured at a protective installation place, determining a zero-sequence current of each line by using a Clark transforming theory; selecting a zero-sequence current signal of which the time window is 10 ms, solving envelope lines, and detecting the form peak valley to the envelope lines of the zero-sequence current of each line; according to the obtained characteristics of the form peak valley, extracting fault line selection criterions of the distribution network, wherein the line with the form peak valley characteristics different from that of other lines is the fault line. The method in the invention is simple for calculating, and avoids the defects that a common calculating method needs transforming in time-frequency domains. The method is good in robustness, strong in transition resistance force, free of interference influence, and strong in practicability. A large number of simulation results show that the method of the invention is accurate in line selection.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a fault line selection method of a distribution network using shape peak and valley detection. Background technique [0002] When a single-phase ground fault occurs in the distribution network, the transient impact current will be generated by the rapid charge and discharge between the system's ground capacitance and the fault point. The circuit is close to an open circuit and has no obvious impact on the inrush current. Therefore, in the same power grid, if the neutral point is not grounded or grounded through the arc suppression coil, the transient process at the moment of the fault is approximately the same. In recent years, Chinese scholars have proposed a method of using traveling waves to realize faulty line selection. The core is the detection of the polarity of the first wave head of the traveling wave. The polarity of the first wave head of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 束洪春王旭戴月涛田鑫萃邬乾晋秦书硕白挺玮
Owner KUNMING UNIV OF SCI & TECH
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