Under high renewable energy penetration, cascade hydro-wind-solar-pumped storage complementary systems face increased risks of curtailment and load loss due to intensified wind-solar fluctuations during peak-shaving operations. To address this issue, a peak-shaving demand and risk mitigation oriented day-ahead scheduling strategy is proposed. First, distinct models are established for the hybrid pumped-storage station under pumping and generating modes. The power coupling relationships between the hybrid pumped-storage station and conventional hydropower, wind, solar, and the power grid are established, as well as the hydraulic coupling relationships among cascade reservoirs. Then, multiple uncertainty scenarios are generated based on wind and solar forecast errors. Finally, a multi-scenario coordinated optimization is performed with the dual objectives of minimizing the residual load peak-valley difference and mitigating the risk of curtailment and load loss. Case studies based on a real cascade hydropower system in the Guizhou Basin demonstrate that the proposed scheduling strategy effectively alleviates curtailment and load loss risks during peak-shaving regulation operations.