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Anti-TA transient imbalance differential protection for generator

A generator and balance technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of sampling value differential action characteristic threshold and inconvenience in slope measurement and tuning.

Active Publication Date: 2005-06-29
BEIJING SIFANG JIBAO AUTOMATION
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Problems solved by technology

However, this method has a shortcoming. Due to the randomness of the initial sampling time, there is a certain fuzzy area in the differential protection of the sampled value, so that the measurement and setting of the threshold and slope of the differential action characteristic of the sampled value are brought to the relay protection staff. Inconvenience

Method used

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  • Anti-TA transient imbalance differential protection for generator
  • Anti-TA transient imbalance differential protection for generator
  • Anti-TA transient imbalance differential protection for generator

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Embodiment Construction

[0011] specific implementation plan

[0012] The present invention implements generator differential protection against TA transient unbalance according to the following formula. Please refer to the definition of installation position and polarity of current transformer and voltage transformer figure 1 In the figure, GS is the generator, MT is the main transformer, TV1 is the common voltage transformer at the machine terminal, TA1 is the machine terminal TA, and TA2 is the neutral point TA.

[0013] The calculation method of differential current and braking current is shown in formula (1):

[0014]

[0015] In the formula: I dz , I zd are differential current and brake current respectively; I T & , I N & are the current phasors of the generator terminal and the neutral point respectively, and they are both pointing to the system as positive.

[0016] In order to improve the action speed of serious internal faults and ensure that external faults do not malfunction, t...

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Abstract

This invention relates to a relay protection method in power system, which discloses an unbalanced transient state generator differential protection method of a TA composed of phase ratio brake property and multiple constant value sampled ratio brake open criteria and applies the algorism of varying data windows and a cyclic block theory. This invention also has the criteria of interconnected detection, out of the zone fault detection, interspaced wire breakage of the current mutual inductor second loop at both sides of the generate and TA saturation.

Description

technical field [0001] The present invention relates to the field of power systems, and more particularly to a method for relay protection. Background technique [0002] Differential protection is a fast main protection for internal faults of generators. In principle, it has natural selectivity, high sensitivity and fast action speed, and is widely used. Field operation shows that the generator differential protection still malfunctions from time to time. In particular, when the external fault is removed or the generator is connected to the grid asynchronously, the differential protection of the generator will malfunction. At present, the action time of the generator differential protection is generally around 20ms, and the time constant of the large unit is relatively large. When there is a large disturbance, the P-level current transformers on both sides (TA for short) Under the action of current, it is difficult to maintain the consistency of the transmission characteri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/06
Inventor 屠黎明苏毅邹卫华
Owner BEIJING SIFANG JIBAO AUTOMATION
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