Transmission network angle stability protectionbased 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.

Switching Operations in 110 kV Networks in the Context of Synchro-Check and Mitigation of Switching Stress by Utilizing Proper Control of Renewables and Energy Storages

“…One of the examples is connected with the circuit breakers: switching operations under 180 degrees (max) phase shift. In other cases, the requirements are provided regarding the short circuit capabilities [21]. One needs to underline that out-of-synchronism switching operations are similar to short circuits since in both cases the points of network, characterized by different voltages, are connected, and the voltage differences cause high-amplitude current flow.…”

“…The recommended settings provided in the literature, as well as the settings in real SC relays, may differ significantly. The authors of [21] specify KPI for synchro-check:…”

Measurement Platform for Latency Characterization of Wide Area Monitoring, Protection and Control Systems

“…To reduce the delay caused by communication, the network topology must also be carefully evaluated [16], [17], and different communication technologies, like supplementary wireless link, can be used to compensate temporary wired network failures [18]. In [19], the experience of the Croatian Transmission System Operator (HOPS) with a PMU-based angle stability protection application is presented. The communication latency due to the different geographical locations of the PMUs installed in their network is discussed.…”