| 摘要 |
PROBLEM TO BE SOLVED: To provide a protective relay device in which unnecessary operation resulting from CT saturation during external accident can be prevented.SOLUTION: In a protective relay device, a data acquisition unit acquires the current data by sampling the current of a power system at a predetermined time interval, and then performing digitization. A CT saturation determination unit determines CT saturation when such conditions that a current variation rate obtained by adding the absolute value of the difference of two continuous data, to four continuous data including the latest data, out of the current data acquired in the data acquisition unit is smaller than a constant multiple of the maximum value of current variation rate in a predetermined period are satisfied. When the CT saturation determination unit determines CT saturation, a relay operation unit locks output of a trip signal for opening a circuit breaker or a switch. |
