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Method for judging D-shaped cable hybrid circuit fault section directing at strong fault and based on fault voltage initial row amplitude value comparison

A fault voltage, mixed line technology, applied in the direction of fault location etc.

Active Publication Date: 2013-09-25
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to solve the problem of distinguishing the fault section of the overhead line-cable-overhead line hybrid line. The present invention proposes a D-type cable based on the comparison of the initial traveling wave amplitude of the fault voltage for strong faults. Method for Discriminating Fault Sections of Hybrid Lines

Method used

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  • Method for judging D-shaped cable hybrid circuit fault section directing at strong fault and based on fault voltage initial row amplitude value comparison
  • Method for judging D-shaped cable hybrid circuit fault section directing at strong fault and based on fault voltage initial row amplitude value comparison
  • Method for judging D-shaped cable hybrid circuit fault section directing at strong fault and based on fault voltage initial row amplitude value comparison

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Experimental program
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Embodiment approach 1

[0048] Implementation Mode 1: The wiring diagram of the simulation system is as follows figure 1 As shown, the voltage level is 220kV, and the sampling frequency is 1MHz. M side system parameters , ; N-side system parameters , ; head-end overhead line , positive sequence impedance per unit length , the zero-sequence impedance per unit length , positive sequence capacitance per unit length to ground , zero-sequence capacitance to ground per unit length , the cable structure is as figure 2 Shown, end overhead line length , the parameters are the same as those of the head-end overhead line. Assume that a single-phase metallic ground fault occurs at a distance of 90km from the head end of the hybrid line cable section.

[0049] The steps of the method for discriminating the fault section of the D-type cable hybrid line based on the comparison of the initial traveling wave amplitude of the fault voltage are:

[0050] (1) After a strong fault occurs on the D-...

Embodiment approach 2

[0054] Embodiment 2: The structure and parameters of the simulation system are the same as Embodiment 1. It is assumed that a single-phase metallic grounding fault occurs at 60 km of the overhead line at the head end of the hybrid line.

[0055] Repeat the steps of embodiment 1 to judge the fault section, same as embodiment one, set the threshold as k set1 set to 0.3, k set2 set to 3, =-10.94, =-1.411, then =9.7534, satisfying the criterion k> k set2 , so it can be judged as a head-end overhead line fault.

Embodiment approach 3

[0056] Embodiment 3: The structure and parameters of the simulation system are the same as Embodiment 1. It is assumed that a single-phase metallic grounding fault occurs at 120 km of the overhead line at the head end of the hybrid line.

[0057] Repeat the steps of embodiment 1 to judge the fault section, same as embodiment one, set the threshold as k set1 set to 0.3, k set2 set to 3, =-1.452, =-12.41, then =0.1170, satisfying the criterion kset1 , so it can be judged as terminal overhead line fault.

[0058] Using the method of the present invention, the different fault locations of the D-type cable hybrid line have been simulated and verified, and the results are shown in the following table:

[0059]

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Abstract

The invention relates to a method for judging a D-shaped cable hybrid circuit fault section directing at a strong fault and based on a fault voltage initial row amplitude value comparison, and belongs to the technical field of alternating current transmission line fault location. The method includes the steps that when the strong fault occurs in a D-shaped cable hybrid circuit, fault voltage data in short time windows at the head end before the fault occurs and at the back tail end after the fault occurs are extracted and undergoes phase-mode transformation, so that mode components are obtained; wavelet transform is conducted on the mode components on the two sides, so that a corresponding mode maximum value is obtained; a specific value of a wave mode maximum value of an initial row of the tail end of the fault and a wave mode maximum value of an initial row of the head end of the fault is used as a judgment feature value, and the D-shaped cable hybrid circuit fault section is judged through comparison of the judgment feature value and a preset threshold value. According to the theoretical analysis and a large number of simulations, the method is good in effect.

Description

technical field [0001] The invention relates to a method for discriminating a fault section of a D-type cable hybrid line based on the comparison of initial traveling wave amplitudes of fault voltage aimed at strong faults, and belongs to the technical field of fault location in electric power systems. Background technique [0002] With more and more overhead line-cable-overhead line hybrid lines in the power grid, how to quickly and accurately determine the fault section after a strong fault occurs on the hybrid line has become a difficult problem for scholars. Overhead line faults are generally transient faults, and starting the reclosing device plays a very important role in the safe, stable and economical operation of the power system; for cable faults, it is generally a permanent fault, and starting the reclosing device after the fault will cause re-damage to the cable. There is no need to implement post-fault reclosing operation. For the hybrid line, there may be case...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 束洪春田开庆张兰兰
Owner KUNMING UNIV OF SCI & TECH
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