After-test simulation method for inner and outer fault recognition of ultra-high voltage alternating-current power transmission line based on lumped parameter T model

A technology of UHV AC and concentrated parameters, which is applied in the direction of the fault location, etc., can solve the problems of poor setting of the setting value, difficult capture of traveling wave signals, and non-repeatable limitations, etc., and achieve excellent operation reliability and sensitivity. Effect

Active Publication Date: 2014-07-02
KUNMING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, since the reliability of the criterion depends on the physical boundary frequency characteristics, there will be a problem that the setting value is not easy to set in practical applications.
The DC traveling wave protection composed of the polarity of the traveling wave head can correctly identify faults inside and outside the zone, but the reliability of the traveling wave protection is limited due to the difficulty of capturing and non-repeatability of the traveling wave signal

Method used

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  • After-test simulation method for inner and outer fault recognition of ultra-high voltage alternating-current power transmission line based on lumped parameter T model
  • After-test simulation method for inner and outer fault recognition of ultra-high voltage alternating-current power transmission line based on lumped parameter T model
  • After-test simulation method for inner and outer fault recognition of ultra-high voltage alternating-current power transmission line based on lumped parameter T model

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1: 1000kV UHV AC transmission line (transmission system structure such as figure 1shown). The line is an eight-split conductor, using a distributed parameter model considering the influence of frequency variation (J.Marti line model according to frequency), the total length of the line is 400km, of which, , , . The C-phase ground fault (C-G) in the UHV AC transmission line area is 200km away from the M terminal, and the transition resistance is 10Ω.

[0023] The steps of the method for simulating and identifying faults inside and outside the UHV AC transmission line area after the test are as follows:

[0024] (1) After a fault occurs on the UHV AC transmission line, the start-up element of the measurement protection is activated, and within a short data window of 3 ms, the zero-sequence voltage on both sides of point M and N at both ends of the UHV AC transmission line is actually measured u M 、u N and zero sequence current i M 、i N (sampling fre...

Embodiment 2

[0028] Example 2: The structure and parameters of the UHV AC power transmission system are the same as Example 1. Phase C ground fault (C-G) occurs outside the UHV AC transmission line in the opposite direction, the transition resistance is 10Ω, the length of the short data window (time window) is 3ms, and the sampling frequency is 20kHz.

[0029] After the extra-high voltage AC transmission line has an external fault in the opposite direction, according to the same method as in Example 1, the zero-sequence voltage on both sides of point M and point N at both ends of the UHV AC transmission line is actually measured u M 、u N and zero sequence current i M 、i N , to calculate the analog current waveform and its correlation coefficient with the measured current waveform, we get =0.3002>0, based on which it is judged as an out-of-area fault.

Embodiment 3

[0030] Embodiment 3: The structure and parameters of the UHV AC power transmission system are the same as in Example 1. Phase C ground fault (C-G) occurs outside the positive direction of the UHV AC transmission line, the transition resistance is 10Ω, the length of the short data window (time window) is 3ms, and the sampling frequency is 20kHz.

[0031] After the UHV AC transmission line fails, according to the same method as in Example 1, the zero-sequence voltage on both sides of the M point and N point at both ends of the UHV AC transmission line is actually measured u M 、u N and zero sequence current i M 、i N , to calculate the analog voltage waveform and its correlation coefficient with the measured current waveform, we get =0.6350﹥0, according to which it is judged as an out-of-area fault.

[0032] Principle of the present invention is:

[0033] 1. Short-window description of fault characteristics inside and outside the UHV AC transmission line area

[0034]...

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Abstract

The invention provides an after-test simulation method for inner and outer fault recognition of an ultra-high voltage alternating-current power transmission line based on a lumped parameter T model and belongs to the technical field of inner and outer fault recognition and protection of an alternating-current power transmission line. An after-test simulation time domain method for inner and outer fault recognition for solving a current response by using an equation i~N=iM-C0*duM / dt+1 / 2*R0*C0*diM / dt+1 / 2*L0*C0*d2iM / dt2 which is met by current zero sequence components on two sides of the line and made according to a Kirchhoff current theory under an outer fault of an ultra-high voltage alternating current power transmission line (the power transmission line is equivalent by using a concentrated parameter T model) in a short data window and an equation which is not met by zero sequence voltage and current components on the fault side under an inner fault is raised. The current on the other side is simulated and calculated by using the actually measured current on one side of the line according to the Kirchhoff current theory; and the current is compared with the relevance of a waveform of the actually measured current, so that the inner and outer faults of the ultra-high voltage alternating current power transmission line can be determined and recognized. The after-test simulation method has the advantages of sensitivity to inner fault recognition, reliability to outer fault recognition and the like, and is suitable for being popularized and used in an ultra-high voltage alternating current power transmission line system.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a post-measurement simulation method for identification of internal and external faults of a model UHV AC transmission line based on a concentrated parameter T. Background technique [0002] The existing UHV AC transmission line protection adopts phase-separated current longitudinal differential protection, optical fiber distance protection as the main protection, and three-stage phase-to-phase and grounding distance protection as backup protection. Split-phase current differential longitudinal protection is the most ideal protection method in principle. It has absolute selectivity, is not affected by system oscillation, is not affected by operation mode, is less affected by transition resistance, and has a phase selection function itself. ; However, when used in long-distance UHV transmission lines, it will be affected by the distributed capacitanc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
Inventor 束洪春何廷一田鑫萃
Owner KUNMING UNIV OF SCI & TECH
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