| 摘要 |
PURPOSE:To obtain a current detecting circuit for protective relay in which current can be detected positively by varying the current detection period optimally according to the frequency of load current and in which the period and frequency of current can be determined at the time of current detection processing. CONSTITUTION:A first processing section 11a detects transition of A/D converted current data from 0 to a value higher than 0 and acquisition of A/D converted current data takes place based on the output from the first processing section 11a. A second processing section 11b detects transition of the A/D converted current data from 0 to a value higher than 0 and current input processing is ended based on the output from the second processing section 11b. Since the current input processing is started and ended through decision processing of A/D converted data, the current input processing can be performed with an optimal current detection period regardless of the frequency conditions of current signal. |
