The implementation of transmission expansion planning towards low carbon development can effectively alleviate the “carbon lock” effect in the power industry and facilitate the transition to low carbon power system. The demand side management(DSM)is able to reduce the needs of power supply and transmission capacity and further bring down the generation coal consumption and transmission losses. It is therefore an important means of carbon emission reduction in power system. The paper analyzes the impact of DSM and low carbon development on transmission planning at first. By analyzing the performance of typical DSM measures in the constraints

a low carbon transmission expansion planning model is established considering DSM. Nonlinear constraints in the planning model are transformed into linear ones using inequality separation method

turning the planning model into a mixed integer linear programming model. The case study shows the effectiveness of the proposed model with IEEE RTS79 system. The results suggest that considering DSM in the transmission expansion planning can effectively reduce the transmission expansion investment and the total carbon emissions

which can improve overall benefits of the power system. This work is supported by National Science Fund for Distinguished Young Scholars(No. 51325702)and State Grid Corporation of China.