| 摘要 |
PURPOSE:To improve the reliability of an apparatus by providing an arithmetic processing part with a voltage level-down detection means in parallel with an analog input means and by processing and operating an voltage, only when there is no input from said voltage level-down detection means between sampling points of time of a system voltage. CONSTITUTION:In an arithmetic processing part 4' when there is an input from a voltage level-down detector 9 with a shorter sampling period between the last and present sampling points of time for a system voltage input. In this manner, sampling of a voltage value in the middle of a sudden change and addition of said value to a difference added value are prevented at the time of a successful high speed reclosing, when an electric system accident occurs or at the time of momentary break of a system voltage input caused by switching of a potential transformer secondary side output, when an electric system operational bus is changed. |
