Transmission network angle stability protection based on synchrophasor data in control centre

Abstract

Angle stability appears in many forms in transmission network. There are small active power oscillations which do not endanger the normal operations whereas medium and large oscillations have implications on normal operations. These latter kinds of oscillations in some cases develop in out of step condition, which is dangerous disturbance with serious impact on transmission network and generating units. Transmission network operator’s challenges and obligations are to treat in the right manner angle stability issues in their network. Controlling and protecting network needs to be done in efficient way in order to disconnect disturbance quickly and prevent abnormal network operation without exporting disturbance in surrounding networks. Synchrophasor measurements in control centre offer a platform, which responds in a new way on angle stability in transmission network. Those measurements which are collected in phasor data concentrators, which is a part of Wide Area Monitoring will be used for creating out of step protection. This is the first step to extended system to Wide Area Monitoring Protecting And Control (WAMPAC). Paper gives progress of such project in Croatian Transmission Network Operator (HOPS). Firstly, there will be stated motives for development of new out of step protection based on synchrophasor measurements. Some feasibility aspect elaborated with emphasis on communications latency. Furthermore, designed Matlab model for transmission network and protection with small portions of simulations results and analyses presented in paper reveal potential of proposed solutions. This new protection is based on using voltage angles values from phasor data stream in phasor data concentrator.