GROUND FAULT OVERVOLTAGE RELAY DEVICE

摘要

A ground fault overvoltage relay device includes: a ground fault detection unit (500) for detecting a ground fault on the basis of the zero-phase voltage of a power system; a first determination unit (100) for determining whether a first condition is satisfied or not, said first condition being that at least two of the line-to-line voltages between respective two phases, which are calculated on the basis of the respective phase voltages of the power system, are less than or equal to a first threshold value; a second determination unit (200) for determining whether a second condition is satisfied or not, said second condition being that the ratio between the minimum value among the line-to-line voltages between the respective two phases and the minimum value among the respective phase voltages is less than or equal to a second threshold value; a third determination unit (300) for determining whether a third condition is satisfied or not, said third condition being that the zero-phase voltage is greater than a third threshold voltage; and a locking unit (400) for, when the first condition is satisfied or when the second condition is satisfied and the third condition is not satisfied, locking the detection output from the ground fault detection unit (500).