Fault direction judgment method based on positive-sequence polarization voltage phase comparison

A polarization voltage and phase comparison technology, which is applied in the direction of fault location, measurement of electricity, and measurement of electrical variables, can solve the problems of inability to correctly judge the fault direction and unfixed distributed power output, and achieve reliable operation, stable operation, and durability. Affected by strong transition resistance capability

Active Publication Date: 2014-10-01
SHANDONG UNIV
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Problems solved by technology

This directional element can only be applied to transmission lines with unidirectional power flow. For distribution lines with distributed power sources, since the output of d

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  • Fault direction judgment method based on positive-sequence polarization voltage phase comparison
  • Fault direction judgment method based on positive-sequence polarization voltage phase comparison
  • Fault direction judgment method based on positive-sequence polarization voltage phase comparison

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[0029] The present invention will be further described below with reference to the drawings and embodiments.

[0030] 1. Performance analysis of directional components when a fault in the positive direction occurs

[0031] when figure 1 When a fault occurs in the F1 position, the working voltage U op And measured voltage U m The relationship between figure 2 As shown, the component on the right side of the M bus belongs to a positive direction fault.

[0032] In a two-terminal power system, when a fault occurs in the positive direction, the phases before and after the positive sequence voltage fault are basically the same, which can be approximated as the positive sequence polarization U after the fault. m1 The phase is equal to the bus voltage U before the fault m(0) Phase, while U m(0) The phase is equal to the system power supply voltage E 1 Phase, therefore:

[0033] arg ( U op U ml ) ≈ arg ( U op E 1 ) - - - ( 1 )

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Abstract

A fault direction judgment method based on positive-sequence polarization voltage phase comparison includes the steps that the measuring voltage Um, the measuring current Im and the bus positive-sequence voltage Um1 at the installation position of a directional element are respectively acquired after a smart distribution network breaks down; a working voltage Uop is set; the direction of the fault is judged. The fault direction judgment method has the advantages that due to limitation of the minimum value, it can be guaranteed that correct actions can be carried out when a short circuit occurs at the tail end of the protection range due to the resistance smaller than the largest transition resistance, and the reverse-direction fault can be judged with high reliability. The fault direction judgment method has the advantages that a voltage dead area does not exist, the capacity for resisting transition resistance is high, the working characteristics are stable, and influences cannot be caused by large changes of the operating mode of a power distribution network system or obvious difference between distributed power supplies or complex load types or other working conditions.

Description

technical field [0001] The invention relates to the field of electric power system relay protection, in particular to a method for judging the fault direction of an intelligent distribution network based on positive sequence polarization voltage phase comparison. Background technique [0002] In recent years, a large number of distributed power sources of different types and capacities have been connected to the distribution network. The improvement of the access level has made the short-circuit current output by the distributed power source sufficient to cause the protection action in the event of a fault, and only rely on the fixed value to ensure the overcurrent Alternative protection schemes cannot meet the requirements of new situations. It is an effective way to solve this problem by configuring the fault direction element on the basis of the original protection, and deciding whether to block or open the protection according to the judgment result of the fault directio...

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Application Information

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IPC IPC(8): G01R31/08G01R31/02
Inventor 丛伟田崇稳王慧史方芳房凡秀鲍乐马龙王瑞
Owner SHANDONG UNIV
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