| 摘要 |
PURPOSE:To test a ground-fault directional relay without interrupting a main circuit power and without removing a ground-fault relay. CONSTITUTION:The ground-fault directional relay comprises a test signal generator 8, an analog OR circuit 3a and an analog AND circuit 4a for synthesizing a test signal and a zero-phase voltage, and an analog OR circuit 3b and an analog AND circuit 4b for synthesizing the test signal and a zero-phase current. Further, the relay comprises an adder 5a for adding an output signal of the circuit 3a and an output signal of the circuit 4a, an adder 5b for adding an output signal of the circuit 3b and an output signal of the circuit 4b, and an arithmetic circuit 20 for deciding a test time and detecting a ground-fault accident from outputs of the adders 5a, 5b. The test signal and a signal from a main circuit are superposed by the circuits 3a, 3b and the circuits 4a, 4b, added by adders 5a, 5b, calculated by the circuit 20, and test and malfunction times are judged. |
