Abstract: Hydropower plants are used as the key supporting power sources responsible for peak shaving, frequency regulation, and ensuring power grid stability in a hydro-wind-photovoltaic multi-energy complementary system. To address load uncertainty in a hydropower-dominated multi- power system, this paper applies the information gap decision theory (IGDT) in developing an IGDT-based peak shaving operation model for the complementary system. We focus on a case study of peak shaving operation for the hydropower stations in the upper Yellow River in Qinghai Province. The results show hydropower operation effectively reduces peak shaving pressure caused by wind power and photovoltaic power on the power system, enhancing power grid stability. For a practical design, we can use the maximum load fluctuation of 45.9% under a risk-averse scenario, or the minimum of 27.2% under an opportunity-seeking scenario, depending on the decision-maker's preference to the risk. These findings help determine robustness boundaries for dispatching decisions and enhance the resilience of a power system.

Key words: hydro-wind-photovoltaic power system, multi-energy complementarity, uncertainty, peak shaving operation, information gap decision theory