Relay protection method and relay protection device for quickly removing dead zone faults of air-charging transformer

Abstract

The invention discloses a relay protection method and device for quickly removing dead zone faults of an air-charging transformer. The method comprises control processes of enabling circuit breakers at all sides of a transformer to be located at an opening position, enabling a current at one side to be changed from no current to current, enabling the circuit breaker at the side to be changed froman opening position to a closing position, and enabling the transformer to be in an air-charging state from the side; performing empty charging of the transformer, and opening dead zone protection forT seconds; enabling a certain non-air-charging side circuit breaker of the transformer to be located at the opening position; wherein the maximum phase current in the non-empty charging side three-phase current is greater than a current setting value, or a zero-sequence current is greater than a zero-sequence setting value, or a negative-sequence current is greater than a negative-sequence setting value; when the conditions are met, a transformer differential protection tripping action outlet loop is started after t1 is delayed, circuit breakers on all sides of the transformer are tripped off, and dead zone faults are rapidly removed. The method is advantaged in that influence of inrush current during empty charging of the transformer is avoided, the method is irrelevant to the transformer backup protection setting value, a transformer type and a fault type, and the dead zone fault removal time is greatly shortened.

Description

technical field [0001] The invention relates to the technical field of relay protection of electric power systems, in particular to a relay protection method and device for quickly cutting off a transformer empty-charging fault in a dead zone. Background technique [0002] Transformer dead zone fault refers to the short-circuit fault that occurs between the circuit breaker on one side of the transformer and the current transformer on this side used for differential protection of the transformer (see figure 2 ), the fault in the dead zone is a fault at the transformer outlet, the fault current is large, and the impact on the transformer is large, and the fault is outside the range of differential protection of the transformer. The fault cannot be isolated, and the fault can only be removed when the backup protection action on the power supply side or the backup protection action on this side trips the circuit breakers on each side of the transformer. [0003] Empty charging ...

AI Technical Summary

Problems solved by technology

[0012] Invention patents 201310641842.0 and 201410039071.2 propose a method for removing transformer dead-zone faults. When a dead-zone fault occurs on one side of the transformer, TA on that side exits the differential protection, making the transformer differential protection trip the circuit breakers on each side. The faults in the dead zones on each side also have the disadvantages of the methods proposed in the invention patents 201310641634.0 and 201310641655.2, and due to the influence of the transformer inrush current during empty charging, the differential protection may not operate or delay the operation.

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