| 摘要 |
PURPOSE:To prevent system voltage from being made unstable, by releasing a breaker with a reactive power compensator and a power system connected to each other, when the generating frequency of overvoltage protecting(OVP)gate pulse comes to a set number or more within a fixed time. CONSTITUTION:When initial OVP gate pulse is generated first, then 1 is counted by a counter 20. In the meantime, from a one-shot circuit 19, one-shot pulse for one second is generated. After that, when second OVP gate pulse is generated within one second after the initial OVP gate pulse is generated, the 2 in counted by the counter 20. Then, by a comparator 22, a value 2 shown by a setting unit 21 and the output value 2 of the counter 20 are compared with each other, and the output of '1' is generated. Then, the output of the one-shot circuit 19 is '1', and so the output of an AND circuit 23 is turned into '1', and the trip command of a breaker is generated. |
