| 摘要 |
PURPOSE:To monitor the input signal system of a protective relay having high sensitivity relay function, where the input waveform is saturated under normal state, positively. CONSTITUTION:System voltage or current is fed through a same input signal circuit to sampling circuits 11-16 and A/D converters 21-26 to produce a low sensitivity digital value and a high sensitivity digital value which are employed in the protective operation at an operating section 3. Deciding sections 61-63 make decisions whether the low sensitivity digital value is in its nonsaturated region whereas deciding sections 64-66 make decisions whether the high sensitivity digital value is in its nonsaturated region. Logical product deciding sections 67-69 make decisions that the input signal system is abnormal when both digital values are in their nonsaturated regions for same phase. |
