Method for enhancing differential protection performance by coordination of mutation quantity fault discrimination and fuzzy harmonic analysis

A differential protection and fault identification technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of protection refusal, internal AD fault, differential misoperation, etc., to prevent false blocking protection, improve sensitivity, Guaranteed effect of sensitivity

Active Publication Date: 2009-12-09
NARI TECH CO LTD +1
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Problems solved by technology

[0003] 1. TA saturation outside the area. Although the products of each company have anti-TA saturation measures, it may still cause protection misoperation during the TA saturation process, or the protection will refuse to operate or delay action when a fault occurs after TA saturation.
[0004] 2. Inrush current

Method used

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  • Method for enhancing differential protection performance by coordination of mutation quantity fault discrimination and fuzzy harmonic analysis
  • Method for enhancing differential protection performance by coordination of mutation quantity fault discrimination and fuzzy harmonic analysis
  • Method for enhancing differential protection performance by coordination of mutation quantity fault discrimination and fuzzy harmonic analysis

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Embodiment Construction

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and examples. However, the invention is not limited to the examples given.

[0032] Such as figure 2 As shown, the method for improving the performance of differential protection by combining the fuzzy harmonic analysis with the sudden change fault discrimination of the present invention, the specific steps are as follows:

[0033] (1), use the inequality (I) to monitor the braking current sudden change ΔI res Is it greater than the criterion open constant K set1 , if inequality (I) is established, then go to step (2); otherwise repeat this step;

[0034] ΔI res >K set1 (I)

[0035] In the formula, the criterion open constant K set1 The value range of is [0.1Ie, 0.3Ie], Ie is the rated current of the transformer;

[0036] (2), judging whether the inequality (II) is established, if the inequality (II) is established, then the fault type be...

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Abstract

The invention relates to a method for enhancing differential protection performance by the coordination of mutation quantity fault discrimination and fuzzy harmonic analysis, which utilizes different characteristics of difference current and braking current mutation quantity to distinguish the internal and external faults of an area under different fault conditions. After a fault type is distinguished by the discrimination method, a fuzzy harmonic analysis criterion is combined to enhance the accuracy of fault discrimination so as to enhance the reliability and sensitivity of differential protection. The method is already adopted in a complete set of protection device of a DSA serial transformer and both the simulation results and the site practical situation indicate that the method has good prevention effect on reasons which easily cause differential misoperation, such as TA saturation, sympathetic surge, AD abnormity, and the like.

Description

technical field [0001] The invention relates to a new method for comprehensively improving the reliability of differential protection by using a novel fault discrimination method combined with harmonic analysis criteria. Background technique [0002] At present, the transformer protection in our country has basically adopted the microcomputer transformer differential protection device, but the accurate operation rate of the protection is generally not high. According to the current relevant data statistics, the current correct operation rate of the transformer differential protection is only about 75%. Can not meet the needs of on-site safe operation. At present, the main reasons for the misoperation of ratio differential protection include the following points [0003] 1. TA saturation outside the area. Although the products of various companies have anti-TA saturation measures, it may still cause protection misoperation during the TA saturation process, or the protection ...

Claims

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Application Information

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IPC IPC(8): H02H7/045
Inventor 张庆伟吕浩代莹梁臣杨胜
Owner NARI TECH CO LTD
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