A Fast Ring-breaking Method for Double-Circuit Lines in Loop Operation

Abstract

The invention discloses a double-loop-line annular operation quick unlinking method which can realize uniform double-loop-line annular operation line load distribution, low line loss and high power supplying reliability and can prevent full-station voltage failure caused by fault of a certain branch line. According to the method, after a female circuit breaker is switched off through standby-protection first-period time delay by a power-supply-side main transformer, before standby-protection second-period time delay action of the main transformer, a branch circuit breaker which is connected with the power supply side on a fault-side bus is quickly switched off, thereby stopping operation of a double-loop-line annular operation circuit. When protection action of a non-annular wiring operation line which is hanged between a power supply side and a load side fails, after the female circuit breaker is switched off through standby protection first-period time delay by the main transformer,a branch circuit breaker which is connected with the fault-side bus is quickly switched off, thereby switching off the path for supplying electric energy of a normal bus to a fault point, realizing purposes of keeping a normal-side bus load and preventing fault range enlargement, and improving reliability of the double-loop-line annular operation circuit.

Description

technical field [0001] The invention relates to a protection method for a transformer substation, in particular to a method for protecting the operation of the double-circuit ring connection of the transformer substation. Background technique [0002] The ring wiring operation mode in which the line switches on both sides of the double circuit line and the bus tie switch on both sides (both sides refer to the power side and load side of the substation) are put into operation can realize even load distribution, reduce line loss, and improve power supply reliability sex. For high-voltage level 110kv double-circuit ring networks on both sides running in parallel, if there is a branch line (the branch line refers to a single-circuit line in the double-circuit line, or a single line connected between the power supply side and the load side) When a branch line circuit breaker refuses to operate or the protection refuses to operate, even if the main transformer backup protection o...

AI Technical Summary

Problems solved by technology

[0004] 1) Equipped with circuit breaker failure protection (that is, adding a device with circuit breaker failure protection), its disadvantage is: it can only solve the situation that the line circuit breaker refuses to operate, and the situation that the line protection refuses to operate will still cause the scope of the accident to expand

Its disadvantage is: it is only suitable for the case of small load, and the line loss is large when the load of the operating line is large

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