This paper proposed a research method based on wind farm power-limited operation. The wind farm power-limited part treated as a special negative spinning reserve, and the interruptible load used as a special positive spinning reserve，the influence of this research method on the frequency modulation of the power grid is analyzed. It used the cost-benefit analysis method to establish the objective functions of the system's minimum start-stop cost, spinning reserve call cost, interruptible capacity cost, power-limited cost of the wind farm, constraint violation cost, and generation cost. It divided several scenarios through the quantification of the power-limited value and the demand for large and small loads. And It uses particle swarm optimization based on the mutation strategy combined with Monte Carlo simulation to solve this model. At the same time, considering the unit output distribution, Improved the model's accuracy. Finally, the calculation results of each scenario are analyzed to verify the superiority of the proposed optimization model.