| 摘要 |
PROBLEM TO BE SOLVED: To provide a current differential relay device capable of preventing a malfunction caused by influences of electromagnetic induction in accordance with an inexpensive method.SOLUTION: In a current differential relay device 1, a ratio differential arithmetic operation section 17 performs ratio differential arithmetic operation on the basis of detection values of a primary current, a secondary current and a neutral point current of a transformer 4. A setting adjustment section 16 adjusts a setting K1 to be a determination reference for the presence/absence of an internal accident of the transformer 4 in the ratio differential arithmetic operation.A setting adjustment section 17 adjusts the setting K1 on the basis of comparing a first determination value ID with a second determination value IM. The first determination value ID is a magnitude of a zero-phase current calculated from the detection values of at least one of the primary current and the secondary current and the neutral point current. The second determination value IM is obtained by inverting a code of either the detection values of the primary and secondary currents or the detection value of the neutral point current and multiplying the neutral point current by a predetermined constant in calculating the first determination value. |
