Optimal design of hydro-wind-PV multi-energy complementary systems considering smooth power output

Photovoltaic (PV) and wind power are intermittent and random, and their grid-connected operation will harm power system stability. Since hydropower has the characteristics of flexible operation and fast start-stop, the integrated operation of hydro-wind-PV can effectively solve the above problem. In this study, a mathematical model and an optimization model of hydro-wind-PV multi-energy complementary systems are established with output smoothness as the objective function and wind and PV surplus as the main constraint. The PV and wind power output scenarios are divided based on the measured data and normal distribution fitting. According to the capacity and output characteristics of hydro-wind-PV, we propose three operation schemes. The schemes are evaluated by comparing the remaining PV capacity and output fluctuation, and uncertainty analysis is introduced to improve the capacity allocation, where the wind-PV complementary system in Scheme 1is taken as an example. The way of bundling unstable wind- PV energy with water energy into the grid makes full use of the abundant local clean renewable energy and enhances the ability to consume unstable power sources. Meanwhile, it can reduce the capacity of energy storage in the energy base to improve economic efficiency and power quality.