复压闭锁引起的变压器后备保护死区分析

复压闭锁过流保护作为变压器主保护的后备保护,反映各种短路故障。不同型号的主变后备保护装置对于保护功能的配置不尽相同,某些只配置高压侧后备的保护装置,在某种特定的运行方式下,其复压闭锁功能会造成后备保护出现死区。一旦在死区内发生短路故障,后备保护将拒动,这将使得该短路故障无法直接切除,进而可能导致主设备损坏。通过对复压闭锁逻辑原理的分析,找出了后备保护死区产生的原因,在此基础上针对不同情况提出了几种简单易行的改进方法。

Analysis of Transformer Backup Protection Dead-zone Coursed by Compound Voltage Locking

Compound voltage locking overcurrent protection is the backup protection for transformer.Different transformer backup protection devices have different protecting function,some devices only have high voltage side backup protection.In certain operation modes,there will be dead-zone in such backup protection.If short fault occurs in this dead-zone,the backup protection device will refuse to trip,so the short fault can＇t be cleared,and then transformer would be destroyed.This thesis analyses the logic of compound voltage locking,it finds the reasons of the backup protection dead-zone,and then it puts forward several simple improvement methods according to different instance.