The high randomness, intermittency and uncontrollability of wind power make large-scale wind power generation present large challenges for integration into a power grid. In this paper, the principles of hydro-wind compensating operation are explored, aiming at improving the power quality of wind power and promoting the integration of wind power into the power grid. Based on the principles of hydro-wind compensating operation, the calculation method of the hydropower compensation capacity for wind power is derived. Then, an optimizing operation model of a hydro-thermal-wind hybrid power system based on the hydro-wind power compensating principle is proposed to minimize the carbon dioxide emissions and obtain optimal operation scheduling of the hybrid power system by taking advantage of hydro-wind compensation and the peak regulation capacity of hydropower. In this model, the baseload and nonbaseload output emission rates are adopted to estimate the carbon dioxide emissions of different power output processes and the emission reduction benefits. Moreover, three scenarios of the operation mode are proposed to demonstrate the applicability of the hydro-wind power compensating principle in practice. The Northwest Power Grid in China is selected as a case study to verify the effectiveness of the proposed model compared to historical operating data. The results indicate that the hydro-wind power compensating principle plays a crucial role in hydro-thermal-wind combined optimal operation. Additionally, the proposed model can improve the wind power generation and reduce the carbon dioxide emissions of the power grid. In particular, the carbon dioxide emissions can be reduced by approximately 1696*10(4) t each year in the Northwest Power Grid. This study provides an approach to schedule optimal operation plans for power grids with large-scale wind power and provides a valuable reference for the large-scale utilization of other kinds of renewable energy worldwide.