The Influence of PID Parameters on Ultra-low Frequency Oscillation in Speed-governor Control System of Hydro Turbine based on PSASP

Regional power grid interconnection brings a series of economic benefits such as power grid staggering peak, hydropower and thermal power complementary, power emergency support and so on. Hydropower plays an increasingly important role in maintaining the stability of the regional power grid with abundant water resources. When the hydropower unit is running, the system power oscillation or even ultra-low frequency oscillation may occur due to the parameter setting of the speed governor control system and the advanced phase operation. In this paper, the 7-type or 8-type hydro turbine governor in PSASP is analyzed, considering the PID control parameters of the speed-governor. The influence of the change of the speed-governor parameters on the ultra-low frequency oscillation of the system is analyzed by the average system frequency response model. Then, by changing the parameter value of the PID regulation module of the hydropower unit, the minimum damping ratio of the characteristic value corresponding to the turbine state variable is compared under different values. The PID parameters are optimized. Finally, the suppression effect of DC frequency modulation parameters on ultra-low frequency oscillation is analyzed.