| 摘要 |
PURPOSE:To orientate accurately the distance to a fault point irrespective of earth system, power supply terminal, and load end, and also independently of the resistance at the fault point, the load, and the earth capacity of a bus, by processing voltage and current data of a local end. CONSTITUTION:The sum of a phase current Ia1 of a fault phase and zero-phase currents I01 and I02 of a faulty line and an adjacent line multiplied by a constant of a transmission line is operated in an adding circuit 15, and the output has the phase shifted in a phase shifting circuit 17 by the phase angle of the positive-phase impedance of the faulty line. A conjugate complex of the subtracted value between currents I01 and I02 is obtained in a subtracting circuit 16, and the output of the circuit 16, the output of the circuit 17, and the phase voltage of the fault phase are multiplied in reactive power operating circuits 18 and 19, and an imaginary component of the output of the circuit 19 is divided in a dividing circuit 20 by an imaginary component of the output of the circuit 18. The output of the circuit 20 is a value corresponding to the absolute value of the positive-phase impedance between the device installation point and a ground-fault point F, and thus, the distance to the fault point is orientated. |
