| 摘要 |
PURPOSE:To enable accurately predicting a step-out of generator, by measuring a phase angle deviation from a revolution detection signal and by deciding that a generator is stepped out, if a future phase angle deviation predicted from said measured value shows a tendency to diverge and takes a given threshold value or more. CONSTITUTION:A phase angle deviation computing means 3 computes a phase angle deviation between a phase angle after the occurrence of a trouble in an electric system and that in a stationary state on the basis of the number of pulses obtained from a revolution detection means 2 and preset data. A phase angle prediction means 4 predicts a phase angle deviation at a future point of time from the computed phase angle deviation. A step-out decision means 5 decides that a generator is stepped out, when a predicted phase angle deviation shows a tendency to diverge and exceeds a certain threshold value. In this manner, a step-out of generator 1 can be predicted accurately and an influence on the system can be prevented beforehand. |
