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Method and apparatus for determining direction of fault

A technology of faults and equipment, applied in the field of determining faults in three-phase power grids, can solve problems such as selective loss of power system protection, and achieve easy and more accurate settings, improved safety and reliability, stable and accurate operation Effect

Active Publication Date: 2013-08-14
ABB (SCHWEIZ) AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This can often lead to a loss-of-selectivity of power system protection

Method used

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  • Method and apparatus for determining direction of fault
  • Method and apparatus for determining direction of fault
  • Method and apparatus for determining direction of fault

Examples

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Effect test

no. 1 approach

[0031] According to a first embodiment, determining the value of the directional phasor quantity includes: forming a cumulative phasor sum of at least two values ​​determined at different times for the electric phasor quantity at the measuring point 10; and setting the cumulative phasor sum to is the value of the direction phasor quantity, Preferably, the sum is formed for the real part and / or the imaginary part respectively. In other words, the cumulative phasor sum of two or more values ​​of the electrical quantity at the measuring point 10 determined at different times and preferably calculated for the real and / or imaginary part respectively can be used as the direction phasor quantity The two or more values ​​of the electrical quantity determined at different times may be determined at fixed intervals or at irregular intervals.

[0032] Figure 3a shows the cumulative phasor sum For example, the cumulative phasor sum is the electric phasor quantity at time t 1 , t ...

no. 2 approach

[0043] According to a second embodiment, determining the value of the directional phasor quantity comprises forming a first cumulative phasor sum of at least two values ​​determined at different times for the first electric phasor quantity at the measurement point, forming the phasor sum at the measurement point A second cumulative phasor sum of at least two values ​​determined at different instants for a second electric phasor quantity, and setting the quotient of the first cumulative phasor sum to the second cumulative phasor sum as the value of the directional phasor quantity . In other words, the quotient of the two cumulative phasor sums of the values ​​of two different electrical quantities at the measuring point 10 can be used as the directional phasor quantity. Each of the two cumulative sums can be formed in a manner similar to that already described above. Equation 3 below shows how one can base on two cumulative phasor sums (the first and and the second and ) t...

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Abstract

A method and an apparatus for determining a direction of a fault in a three-phase electric network, the apparatus comprising means (10) for determining a value for a directional phasor quantity at a measuring point in the three-phase electric network after a fault has been detected in the three-phase electric network, and means (10) for comparing the determined value for the directional phasor quantity with a directional operation characteristic to determine the direction of the fault from the measuring point, wherein the means (10) for determining the value for the directional phasor quantity comprises means for forming a cumulative phasor sum of at least two values, determined at different instants of time, of an electric phasor quantity at the measuring point; and means for setting the cumulative phasor sum as the value for the directional phasor quantity.

Description

technical field [0001] The invention relates to determining the direction of a fault in a three-phase power network. Background technique [0002] A reliable indication of the direction of the fault, i.e. whether the fault is in the forward or reverse direction from the measuring point, may be useful in power system protection where fault current may flow through the measuring point in both directions Pivotal. Correct directional information is important for the selective operation of the protection system so that only eg faulty feeders or faulty feeder sections are correctly isolated. [0003] Several methods exist for fault direction determination in power system protection. A typical implementation of a directional element is as follows: The measured current and voltage are first digitally sampled and then converted into Complex phasor. Direction determination can be based on, for example, any of the following electric phasor quantities (usually calculated at the fund...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/088H02H3/081H02H7/26
Inventor 阿里·瓦尔罗斯扬内·阿尔托宁
Owner ABB (SCHWEIZ) AG