| 摘要 |
PURPOSE:To prevent mistrip by providing a power flow detector, a contactor switching commander, a time limit device, an AND gate and an interruption commander, and judging that power is not interrupted when power flow is brought to zero due to fluctuation of load or output. CONSTITUTION:When power flow is zero, a power flow detector 51 provides signals A to a contactor switching commander 53 and an AND gate 55. Upon reception of the signal A, switching commander 53 in a contactor provides a signal B to a time limit device 54 and provides a switching command C to a switching contactor 13 thus switching the tap from (b) to (c). Upon reception of the signal B, the time limit device 54 provides a signal D to the AND gate 55. Upon reception of the signals A and D, the AND gate 55 makes judgement of power interruption of an external power system and provides a signal E to an interruption commander 52. Upon reception of the signal E, the interruption commander 52 provides an interruption command F to a link circuit breaker 2 thus opening the link circuit breaker 2 and separating the power system 1. |
