220kv transformer dead-zone fault removing method

Abstract

Disclosed is a 220kv transformer dead-zone fault removing method. The fault removing method can prevent relatively long fault removing time, and can prevent damage to the transformer. According to the technical scheme, the fault removing method comprises the steps that fault characteristics are analyzed; and judging criteria are proposed according to the fault characteristics: 1) when a backup protection tripping outlet on the transformer side exists, a relay is in an action state; or other protection tripping outlet exists, the relay is in an action state; and 2) the A phase, or B phase or C phase current on the transformer side is greater than a setting value, or a zero-sequence current or a negative-sequence current is greater than the setting value; when the above two conditions are fully satisfied, the transformer differential protection TA on the transformer side is quitted after a certain time delay; namely, the current on the transformer side does not participate in the transformer differential protection current calculation; when any one of the two conditions is not satisfied, the transformer differential protection TA on the transformer side is connected immediately by zero second; and namely, the current on the transformer side participates in the transformer differential protection current calculation.

Description

technical field [0001] The invention relates to a method for removing faults in the dead zone of a 220KV transformer. Background technique [0002] At present, the microcomputer transformer protection is divided into four parts: differential protection, backup protection, failure protection and body protection. Among them, the differential protection is the main protection of the transformer, which can respond sensitively and quickly to various faults within its protection range. When a fault occurs between the current transformers and circuit breakers on each side of the 220kv transformer, the fault is outside the differential protection range of the transformer, but within the differential protection range of the bus on the fault side. Although the bus differential protection on this side or the backup protection on this side of the transformer trips the circuit breaker on this side of the 220kv transformer, the fault still exists. These faults are only removed by the back...

AI Technical Summary

Problems solved by technology

Although the bus differential protection on this side or the backup protection on this side of the transformer trips the circuit breaker on this side of the 220kv transformer, the fault still exists. These faults are only removed by the backup protection on the power supply side of the transformer, but the time limit for the backup protection is relatively long. It is the failure of the transformer outlet, which is easy to cause damage to the transformer

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