GROUNDED LINE SELECTING RELAY FOR MULTIPLE LINE SYSTEM

摘要

PURPOSE:To select a faulty circuit surely by detecting a grounded fault line from a zero-phase voltage, a current change before and after the occurrence of ground fault and a current-phase relation to the operation result from the period of time from the point of time of detection of the ground fault to the time when a load current positive-phase-sequence component exceeds a specified value. CONSTITUTION:A first grounded line selector 31 inputs the output S17 of an operation part 26, the digital quantity of a zero-phase voltage V0 to be the output S7 of a data conversion part 16 and the timer set point of the other party end preceding cutoff detector S20 and outputs a grounded line determination signal S23 or S24 upon ground fault on a line 3 or 4. In a selector 33, when the zero-phase voltage V0 is a polar voltage in the same way as the selector 31, the active component of IRY2 is higher than a specified value and a grounded line determination signal S26 or S27 is outputted from the code of the effective component.