| 摘要 |
PURPOSE:To prevent a synchronous machine from overexciting at a low frequency by controlling in phase back when the control voltage of a field breaker tripping circuit becomes lower than the prescribed value or when the trio interlock of the machine is operated. CONSTITUTION:An exciting voltage forming circuit 4 normally controls a thryistor exciter 11 in response to a deviation signal 130 between the output voltage 110 of a synchronous machine 1 and a voltage set value 120. The fact that the control voltage of the trip circuit of a field breaker 5 becomes lower than the prescribed value or that a synchronizing trip interlock is operated is detected at the abnormal time when the machine 1 is disconnected from a system 3, and a control circuit 9 control in phase back the circuit 4, thereby reducing the exciting current. In this manner, the low frequency overexcitation of the machine can be prevented. |
