Generator industrial-frequency variation equantity rate difference protection method

A technology of power frequency variation and ratio differential, which is applied in the direction of emergency protection circuit devices and electrical components, can solve the problems of low sensitivity, low fault point potential, loss of reliability, etc., and achieve the effect of good reliability and high sensitivity

Inactive Publication Date: 2003-05-21
NR ELECTRIC CO LTD
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Problems solved by technology

[0004] 1) For slight faults between phases inside the unit, the protection is easily affected by the load current, and the sensitivity is low, especially in the case of heavy loads, it may not be able to operate
[0005] 2) The ...

Method used

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  • Generator industrial-frequency variation equantity rate difference protection method
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  • Generator industrial-frequency variation equantity rate difference protection method

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Embodiment Construction

[0035] The generator power frequency variation ratio differential protection method is realized by a microcomputer protection device, which is a commonly used device in this technical field (see CN99114518 and CN93114341 of the applicant). The power frequency variation of the machine terminal current and neutral point current of the generator transformer microcomputer protection device constitutes a highly sensitive power frequency variation ratio differential element to detect small currents that cannot or are difficult to reflect by conventional steady-state ratio differential Fault: The formula of the sensitive power frequency variation proportional differential is as above:

[0036] ΔI d : Variation of power frequency of differential current

[0037] ΔI d =|ΔI 1 +ΔI 2 |

[0038] ΔI 1 , ΔI 2 Respectively, the power frequency variation of the generator outlet and the neutral point current of the generator

[0039] ΔI r : braking current power frequency v...

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Abstract

A protection method of the industrial frequency variation ratio differential motion in the generator. A industrial frequency variation ratio differential motion element with high sensitivity is formed by the power variation of the machine-end current and neutral-point current in the generator microcomputer protection equipment and can be used to detect the low current fault which can not be or rarely be reflected in the routine steady ratio differential motion. The invention only reflects the fault component, and is unaffected by the load current in the normal running of the generator and transformer and is very little affected by the transition resistance. It adopts the high brake coefficient anti-TA (the current mutual inductor) saturation, and uses the floating threshold technology. The protection has a high sensitivity and a good reliability.

Description

1. Technical field [0001] The invention relates to a relay protection method, in particular to a generator power frequency variation ratio differential protection method. 2. Background technology [0002] The relay protection device is an important part of the safe operation of large-scale installations such as generators and transformers in the power grid. The generator power frequency variation ratio differential protection fully reflects the variation of differential current and braking current, and is not affected by the load current during normal operation. It can sensitively detect minor internal faults of transformers and generators. At the same time, the braking coefficient of the power frequency variation ratio differential is relatively high, and its ability to withstand TA (current transformer) saturation is relatively strong. [0003] At present, the existing generator differential protection has the following problems in protecting the internal minor faults of ...

Claims

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Application Information

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IPC IPC(8): H02H7/06
Inventor 郑玉平沈全荣陈松林李海英沈国荣
Owner NR ELECTRIC CO LTD
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