Anti-TA saturation differential protection method and device for transformer

A differential protection device and differential protection technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of current differential protection misoperation, TA transient saturation, etc., and achieve the effect of improving accuracy and accurate judgment

Active Publication Date: 2016-06-22
HENAN XJ INTELLIGENT CONTROL TECH
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AI Technical Summary

Problems solved by technology

When disturbances such as no-load closing and external faults occur during the operation of the system, the transformer and current transformer (TA) are accompanied by complex transient processes. At this time, it is very likely to cause TA transient saturation, resulting in current differential protection. Misoperation

Method used

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  • Anti-TA saturation differential protection method and device for transformer

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Embodiment Construction

[0038] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0039] The present invention proposes a differential protection method for transformers against TA saturation. The method mainly includes the fault initial moment, judging the fault in the zone (or outside the zone) and the judgment of the fault in the zone from outside the zone to the zone. The following will be explained in sequence

[0040] 1. Determine the start time of the fault

[0041] The determination of the fault start time directly affects the accuracy of the judgment of the fault in the area and the fault outside the area. Therefore, it is very important to determine the start time of the fault accurately. The AC transformer (TA) protection caused by internal faults or external faults is usually accompanied by a large braking current. Therefore, the present invention uses the moment when the braking current appears as the basis fo...

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Abstract

The invention relates to an anti-TA saturation differential protection method and a device for a transformer. The differential protection method comprises the steps of collecting the current of a to-be-protected element; collecting N current sampling points with a current cycle; determining a starting time of a fault; on the condition that the variation of a braking current and the variation of a differential current occur simultaneously, judging the occurrence of an internal fault and starting the differential protection; on the condition that the variation of the braking current occurs before the variation of the differential current, judging the occurrence of an external fault and locking the differential protection; during the occurrence of the external fault, judging the conversion of the fault type from the external fault to the internal fault and starting the differential protection. According to the invention, whether an internal fault or an external fault occurs can be judged more accurately based on a preset criterion. Therefore, the differential protection malfunction of the current can be effectively prevented.

Description

technical field [0001] The invention relates to a transformer anti-TA saturation differential protection method and a device thereof, belonging to the technical field of microcomputer relay protection. Background technique [0002] As an important equipment in the power system, the power transformer is widely used in power transmission and distribution. How to ensure the safety and stability of the transformer is the basic requirement for the operation of the power system. At present, the current differential protection is mainly used as the main protection of the transmission line of the transformer. Among them, the differential protection has the characteristics of simple and reliable principle, high sensitivity and fast operation speed. When disturbances such as no-load closing and external faults occur during the operation of the system, the transformer and current transformer (TA) are accompanied by complex transient processes. At this time, it is very likely to cause T...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/045
CPCH02H7/0455
Inventor 羊阳刘永祥汪战魁陈龙兴张长炜张洋豪张娟杨威振时洋高盼
Owner HENAN XJ INTELLIGENT CONTROL TECH
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