Abstract: Many small hydropower stations in mountainous power grids have a light load.When combined with the integration of a large number of new energy sources, this can cause the transmission section to be overloaded during the summer peak season, limiting the export of clean energy and threatening the safety of power grid equipment.To address this issue, a protection action strategy that coordinates overload protection with adjustable power sources is proposed to achieve optimal control effectiveness.Firstly, the power transmission path from the power source to the cross-section is determined based on the current tracking method, and the impact of a single power source on the overload line is determined based on power sensitivity analysis.Subsequently, a multi-objective optimization model is established to minimize system transmission power loss and maximize system safety margin after protection action.The approach aims to maximize system safety margins by optimizing power output and protection action while minimizing the frequency of protection actions required.Finally, simulation verification is carried out using a power grid in a specific mountainous area, as an example, demonstrating the effectiveness of the established model.