GROUND-FAULT PROTECTION RELAYING SYSTEM FOR POWER DISTRIBUTION LINE

摘要

PURPOSE: To enhance a ground-fault accident detecting capacity in a system always having a large residual current in a ground-fault protection relaying system. ;CONSTITUTION: An effectively grounded power distribution system has a ground- fault overcurrent relay 8 to be operated when the amplitude of a zero-phase current is a predetermined value or more and a zero-phase current variation relay 9 to be operated when the variation of the zero-phase current is a predetermined value or more. When the relay 8 is operated, it is protected by the ground-fault overcurrent relay. When the relay 8 is not operated, it is protected by the relay 9 under the condition of non-operation of the ground- fault overcurrent relay.;COPYRIGHT: (C)1993,JPO&Japio