Stability and dynamic response of two-stage hydropower stations cascaded by regulating reservoir

Abstract

This paper studies the stability and dynamic response of two-stage hydropower stations cascaded by regulating reservoir. Firstly, the model of the two-stage hydropower stations cascaded by regulating reservoir is established. Then, the stability and dynamic response of two-stage hydropower stations are analyzed. Finally, the effects of sectional area of regulating reservoir on the stability and dynamic response based on the first-stage and second-stage hydropower stations are analyzed. The critical stable sectional area of regulating reservoir is determined. The results show that, the stable domain of the first-stage hydropower station is smaller than that of the second-stage hydropower station because of the feedback mode of water level of regulating reservoir and parameters of two-stage hydropower stations. The sectional area of regulating reservoir has a remarkable influence on stable domains and dynamic response processes. Under different combinations of proportional gain and integral gain of governor, the critical stable sectional area of regulating reservoir has two positive solutions. The intersection, curves of the critical stable sectional area of regulating reservoir and integral gain of governor, divides the parameter plane into stable domain and unstable domain. The stability of two-stage hydropower stations becomes better with the decrease of integral gain of governor.