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Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method

A differential protection, abnormal state technology, applied in emergency protection circuit devices, electrical components and other directions, can solve the problems of slow discrimination, easy to block by mistake, etc., to achieve the effect of fast discrimination, high reliability and improved sensitivity

Inactive Publication Date: 2008-11-12
NR ELECTRIC CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, there are defects in principle, namely: slow discrimination speed, easy to block by mistake, etc.

Method used

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  • Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method
  • Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method
  • Transformer differential protection difference stream and differential protection instantaneous TA abnormal state identification protecting method

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Embodiment Construction

[0029] (1) Discrimination of abnormal alarm of differential current in transformer differential circuit based on ratio braking principle. Its action equation is described in detail as follows:

[0030] I d > I bj _ set I d > kI r I r = 1 2 Σ t = 1 m | I ...

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Abstract

The invention is a method of identifying and protecting differential protective difference current and differential protective transient TA abnormal state of a transformer. The differential abnormal alarming adopts ratio brake principle, the difference current abnormal alarming threshold value varies with the variation of load current of the transformer, when a phase difference current meets a condition, send out an abnormal alarming signal in no need of locking differential protection, the differential current initial value should be adjusted by avoiding the exciting current of the transformer, generally 0.03Ie, where Ie is rate current of the transformer, combine industrial frequency variation quantity voltage opening component and the current quantity, the distinguishing principle of differential protective loop transient TA breakage and short-circuit is allowable type, when differential protection starts and then meets conditions, consider it is a failure condition to open differential protection, and otherwise consider it is a start of differential protection caused by differential loop TA abnormality.

Description

1. Technical field [0001] The present invention relates to differential protection differential current of transformers and a method for identification and protection of instantaneous TA abnormal state of differential protection, especially the principle of differential current abnormal identification of differential circuit of ratio braking transformer and the combination of power frequency variation, voltage open element and current. A new method for identifying abnormal states such as instantaneous TA disconnection and short circuit of differential protection. 2. Background technology [0002] At present, the commonly used method for distinguishing the abnormal alarm of the differential current of the transformer differential circuit is: when any phase differential current is greater than the differential current alarm setting (I bj_set ) for more than 10 seconds, an abnormal differential current alarm signal will be issued, and the differential protection will not be blo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/045
Inventor 陈松林李海英郑玉平金勇沈国荣
Owner NR ELECTRIC CO LTD