Optimization and service lifetime prediction of hydro-wind power complementary system

Abstract

Wind power is the most potential clean renewable energy. However, due to the uncertainty of wind energy, its grid connection is limited, resulting in wind curtailment. To address these challenges, a novel model of combining wind power and hydropower is proposed by using reservoir energy storage in this paper, which uses dual cycle control, i.e. the primary frequency control and power complementary control to ensure the power quality and realize the requirement of high proportion wind power grid connection, and two indexes: the capacity ratio of wind power to hydropower (α) and the capacity ratio of the complementary system to the power grid (β), four objective functions as well as a service lifetime model are proposed to optimize the complementary system. The research shows that there are three typical variations, i.e., the variation caused by abrupt wind speed, the positive and negative co-variations between wind power and objective power. The positive co-variation is beneficial to the stability of hydro-wind power complementary system, while the other variations bring certain risks. Furthermore, under the premise that hydropower undertakes dual tasks: regulating power quality and compensating wind power, the stability and power quality of the complementary system are guaranteed when β is within 25%. If hydropower units are not responsible for regulating peak demand,β will increase from 25% to 40%. In addition, according to the proposed lifetime model, if the frequency deviation meets the allowable value, the maximum service lifetime of hydropower units reduces by 15%. Otherwise, the service lifetime will decrease rapidly. The results provide reference for developing variable renewable energy in the future.