POWER LOAD IMBALANCE DETECTION DEVICE AND POWER LOAD IMBALANCE DETECTION METHOD

摘要

First through third phase voltage level determining devices (30-32) output signals, respectively, when any of the first through third phase impedance values fall below a reference value among the three phase voltages representing transmission grid voltages. When an output signal is received from all of the determining devices, a grid-fault detecting AND circuit (33) outputs a grid fault detection signal indicating that a major grid fault has occurred among the various types of grid faults that may occur. A rate-of-change detector (19) outputs a rate-of-change detection signal when the change in the value of a generator end current (18) exceeds a given setting. A logic circuit (46), which includes an OR circuit (23) and an AND circuit (24), outputs inflowing steam volume reduction signals (26) based on grid fault detection signals or rate-of-change detection signals.