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Method of current transformer saturation identification and method of current differential protection on saturation thereof

An identification method and current waveform technology, which is applied in the electrical field, can solve the problems of slow detection time, misoperation, existence, etc., and achieve the effect of small influence and prevention of misoperation

Inactive Publication Date: 2005-07-06
XJ ELECTRIC +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006]The main disadvantage of the above-mentioned waveform distortion feature detection method is that the detection time is slow and requires at least two cycles, which will greatly reduce the protection action speed and affect the protection performance. overall performance
[0007]The current technology increases the K value to 0.9 after TA saturation is detected. However, when TA saturation is seriously caused by an external fault, the possibility of misoperation still exists

Method used

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  • Method of current transformer saturation identification and method of current differential protection on saturation thereof
  • Method of current transformer saturation identification and method of current differential protection on saturation thereof
  • Method of current transformer saturation identification and method of current differential protection on saturation thereof

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Embodiment Construction

[0027] Describe the detailed content of the present invention in detail below:

[0028] 1. Realization of short-window rapid exit for faults in the zone

[0029] When TA is saturated, because TA has a period of linear transition time (3~5ms) before saturation, the fault component of the protection phase-separation differential element makes full use of this non-saturated linear transition time and short window data of 4ms~5ms to detect faults , if a fault in the zone is detected, it can be exported quickly, thereby avoiding the impact of TA saturation on protection. It should be noted that since the short-window data at the initial stage of the fault contains a relatively large harmonic component and is a point of rapid exit, the action threshold of the fault component phase-separated differential element should be appropriately increased and the K value should be increased.

[0030] 2. Realization of real-time investment in TA saturation

[0031] Through the analysis of the...

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Abstract

This invention refers to a TA saturation identifying method and current differential protection method for same, which adopts the sectional wave shape integral method to judge whether the TA occurring, it needs a cycle and is simple and effective, said method does not influence protection action speed in area serious fault and effectively prevent error action in out area fault. Said invention is a self-adaptive method with very less influence to performance of protected unit.

Description

technical field [0001] The invention relates to the field of electricity, in particular to a method for identifying the saturation of a TA (current transformer) in the relay protection of a high-voltage power grid, and also relates to a method for current differential protection when the TA is saturated. Background technique [0002] In the high-voltage power grid, the current transmitted on the high-voltage line is usually hundreds of amperes to thousands of amperes. Such a large current needs to be converted into a secondary small current of 1A or 5A specification by TA (current transformer) and introduced into the relay protection device. Under normal circumstances, the secondary output current of TA can truly reflect the primary current of the line, but in the case of a fault, due to the large fault current and the effect of the DC component in the fault current, the iron core is quickly saturated, so the primary current becomes the excitation current. The secondary curr...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/26
Inventor 张学深李瑞生王强路光辉王尔寒桑中庆
Owner XJ ELECTRIC