| 摘要 |
PURPOSE:To calculate the distance to a short-circuited failure point only by a voltage, current, and known data obtained at an own terminal electric station when locating the short-circuted failure point on a single circuit. CONSTITUTION:Currents Ia-Ic of respective phases of the circuit 3 are detected by a current transformer 4 provided at an own electric station of the circuit 3 and voltages Va-Vc of respective phases are detected by a transformer 5 provided to a bus 2A. Each detected amount is supplied to a voltage dividing analog filter circuit 12 through a transformer 11 for insulation to be voltage-divided to a necessary value, and then sampled and held by a sample holding circuit 13, whose output is inputted to a multiplexer circuit 14. Amount signals outputted from this circuit 14, one after another, are converted by an A/D converter 15 into digital values, which are then stored in a memory circuit 16. This memory is stored by A/D-converted values as many as cycles necessary to calculate voltage and current values before and after the failure. An arithmetic processing circuit 17 consists of, for example, a microcomputer, etc. Of course, a digital IC, etc. are usable. |
