| 摘要 |
PURPOSE:To avoid transient reaction by using a self-terminal current data at a time earlier than the current data of a counterpart terminal for the suppressed current operation. CONSTITUTION:The current of a power transmission line 1 is detected by a CT2, digitally converted and transmitted to a counterpart terminal by a communication device 11 through a communication coupled circuit 7 for transmission, while it is sent to a differential determination circuit 10 by delaying it through the 1st delay circuit 9 and the 2nd delay circuit 12. The differential current and suppressed current are found from the current of the counterpart terminal sent out from the counterpart terminal through the communication device 11 and a communication coupled circuit 8 for receiving. The delay circuit 9 compensates the transmission lag in the current signal of the counterpart terminal, the output of which is used for the operation of the differential current. The delay time of the 2nd delay circuit 12 is shorter than that of the 1st delay circuit 9 and is used for the operation of the suppressed current. The suppressed current thereby rises earlier than the response of the differential current, so that transient reaction can be avoided. |
