The method of detecting asynchronous power swing based on the variation of active power

Asynchronous power swing is a seriously abnormal operation status in power system. When this circumstance occurs, the current, voltage and transmission power in the network will fluctuate periodically, which may seriously damage the generators, motors and other devices. If the power swing can be controlled in time, the system may be stable again. If the control measures are failed, the system will be out of step. The power swing decoupling devices will operate to decouple the network into several independent subnetworks. Power swing protection is the last line of defence for power stability. In this paper, a criterion based on the variation of active power is proposed for detecting asynchronous power swing.