Frequency stability simulation considering underfrequency load shedding relays, special protection automatics and AGC software models

Integration of the interconnected power system (IPS) of Ukraine to the European Network Transmission System Operators for Electricity (ENTSO-E) requires an improvement of the automatic emergency control and harmonization with the load-frequency control according to the requirements of ENTSO-E. In order to investigate the frequency and active power control, it is necessary to develop the detailed simulation model, which includes models of automatic under frequency load shedding (UFLS) and automatic frequency reclose (AFR) relays, special protection automatics (SPA) of the nuclear power plants, automatic generation control (AGC) and 750-220 kV transmission networks of IPS of Ukraine. The frequency stability phenomena have been studied by time domain simulation using the detailed model, implemented in DIgSILENT PowerFactory software. The simulation results for different disturbances are presented in this article.