APPARATUS FOR COUNTERMEASURE AGAINST BREAKER OPERATION FAILURE

摘要

PURPOSE: To avoid the loss of fail-safe conditions or the failure of ordinary monitoring even if a bus-bar is shutdown by selective cut-off at the time of breaker operation failure by a method wherein the failure detection condition of a line protective device is converted into a one-shot signal. ;CONSTITUTION: When a failure detection condition 6d is inputted from a line protective device when a breaker operation is failed, a signal 6e is outputted by a one-shot timer 15 for a certain period (t₂). With this constitution, even if a bus-bar is shutdown by selective cut-off at the time of breaker operation failure and the failure detection condition 6d is outputted continuously, the operation of a fail-safe relay 32 is not continued and the loss of fail-safe conditions or the failure of ordinary monitoring can be avoided. Further, in accordance with a time chart, the setting time (t₂) of the one-shot timer 15 must be shorter than the setting time (t₃) of an ordinary monitoring failure detection timer 16, i.e., (t₃)(t₂), and longer than the setting time (t₁) of a breaker operation failure detection timer 9, i.e., (t₂)(t₁).;COPYRIGHT: (C)1993,JPO&Japio