Comparative studies on load frequency control for islanded distribution network connected with mini hydro

IEEE working group on prime movers recommended different governors for hydro power plants. This paper presents the comparative studies on all of these governors for mini hydro power plants (MHPP) operating in parallel and supplying power to distribution network. The purpose of this study is to find their suitability in controlling the frequency of the system for large load variations in an islanded distribution network. The mini hydro power plant with its distribution network is modeled in PSCAD software. The mechanical hydraulic governor, electro hydraulic PID governor, electro-hydraulic PI governor and Enhanced governor are evaluated one by one to find the best response in controlling frequency when disturbance occurs. The load variations from 10% to 50% both addition and reduction are tested for every governor. This study will assists in selecting a particular governor for isolated mode, interconnected mode as well as for islanding mode of operation in distributed generation.