Integration of Hydro–Wind–PV Power Under Cold-Wave Conditions

With the growing risks posed by extreme weather, such as cold waves, to the secure operation of power systems integrated with large-scale wind and PV power, conventional multi-energy complementary modes fail to cope with the drastic output fluctuations in renewable resources. In this study, a hydro–wind–PV joint-optimized scheduling model is established to quantify the compensation requirement of wind–PV power output fluctuations and to optimize the hydropower compensatory regulation, aiming to clarify the actual effects and inherent limitations of hydropower under cold-wave scenarios. Based on 86-year hourly operational simulation data of a practical virtual case in northwest China, the main simulation results, limited to a daily time horizon with five statistically extracted scenarios, are as follows: First, cold-wave events significantly raise the peak shaving and compensation pressure of hydropower, with the maximum fluctuation amplitude of new energy output reaching 86.76%. Second, compared with conventional operating conditions, hydropower can satisfy the above compensation demand, whereas the reservoir water level deviates from the normal range by −2.2–3.0 m after scheduling, which leads to water consumption or effective storage occupation of reservoirs. Third, restricted by the hydropower installed capacity and reservoir regulation constraints, the power deficit of 1962 MWh and water spillage of 10.59 million m3 cannot be completely resolved. This study can provide theoretical support for analyzing wind–PV fluctuation risks and revealing the multi-energy coupling operation mechanism in cold-wave environments.