Fault distance measuring method for hybrid transmission lines based on unknown parameters.

A transmission line, fault location technology, applied in the fault location, detection of faults by conductor type, etc., can solve the problems of no longer uniform and continuous line impedance, line protection and influence of distance measurement results, etc., to achieve a clear method and high application value. , the principle of reliable effect

Active Publication Date: 2018-05-08
STATE GRID JIANGSU ELECTRIC POWER CO WUXI POWER SUPPLY CO +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Once a single overhead line is changed to a hybrid transmission line composed of cable lines and overhead lines, the impedance of the entire line will no longer be uniform and continuous, and the results of line protection and distance measurement will be easily affected

Method used

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  • Fault distance measuring method for hybrid transmission lines based on unknown parameters.
  • Fault distance measuring method for hybrid transmission lines based on unknown parameters.
  • Fault distance measuring method for hybrid transmission lines based on unknown parameters.

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Embodiment Construction

[0036] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0037] The cable-overhead line mixed transmission line is connected to the double-ended power supply system such as figure 1 As shown; a two-stage hybrid transmission line composed of a section of overhead line and a section of cable is connected between the M-side busbar of the substation and the N-side busbar of the substation; the three-phase system is represented by a single line, and the power supplies on both sides of the system with double-ended power supply are E. M ,E N ; P is the connection point between overhead lines and cables; MP section uses overhead lines, and NP section uses cables;

[0038] figure 2 is the positive-sequence equivalent network when a short-circuit fault occurs on the hybrid transmission line; the positive-sequence impedance per unit length of the overhead line in the MP section is Z a1 , the length of the MP segment is l ...

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Abstract

The invention provides a fault distance measuring method for hybrid transmission lines based on unknown parameters. A hybrid transmission line includes a section of overhead line and a section of cable line. The fault distance (x) is obtained by eliminating the influence of the positive sequence impedance per unit length of the overhead line, the negative sequence impedance per unit length of theoverhead line, the positive sequence impedance per unit length of the cable line and the negative sequence impedance per unit length of the cable line in the hybrid transmission line. The fault distance measuring method has the advantages as follows: (1) the principle is reliable, and the precision of distance measurement is high; (2) the method is clear, the equation is solved without pseudo root, and a specific fault distance analysis formula is given; and (3) the value of practical application on an engineering site is high.

Description

technical field [0001] The invention relates to the technical field of electric power automation, in particular to a fault location method with unknown parameters of hybrid transmission lines. Background technique [0002] In recent years, cable lines have been widely used in urban power supply networks and substation incoming and outgoing lines. Compared with the original overhead transmission lines, they are economical, beautiful and practical. When the transmission line adopts a single overhead line, its line impedance is uniform and continuous. Once a single overhead line is changed to a hybrid transmission line composed of cable lines and overhead lines, the impedance of the entire line will no longer be uniform and continuous, and the results of line protection and distance measurement will be easily affected. The fault location research of hybrid transmission lines has always been a hot spot. At present, it is a new research to take the unit length impedance of the o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/085
Inventor 李澄鲍有理邵亮严伟严慧王浩高阳王涛李欣哲张誉龄
Owner STATE GRID JIANGSU ELECTRIC POWER CO WUXI POWER SUPPLY CO
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