Broken wire detection functional attaching protective control control equipment

摘要

PURPOSE:To prevent the malfunction at the time of the breaking of a wire of an instrument transformer by comparing each phase voltage and each line voltage with given set values, respectively. CONSTITUTION:A phase voltage comparing part 1 compares the magnitude of the secondary circuit each phase voltage Va, Vb, Vc of an instrument transformer with a first set value K1 and outputs a signal '1' to an AND circuit 2 when each phase voltage Va, Vb, Vc is smaller than the set value K1. Also, a line voltage comparing part 3 compares the magnitude of the secondary circuit each line voltage Vab, Vbc, Vca of the instrument transformer with a second set value K2 and outputs the signal '1' to an AND circuit 4 when each line voltage Vab, Vbc, Vca is larger than the set value K2. Then, the output signal of the AND circuits 2, 4 is inputted to an AND circuit 5. That is, at the time of Va, Vb, VcK1, a breaking of wire-detecting signal '1' is outputted from the AND circuit 2 and only when the output signal of the AND circuit 4 is '0', the output signal of the AND circuit 5 is '1' to be used as a signal for locking protecting and controlling functions.