Collaborative optimal scheduling for coupled transmission and distribution systems considering HVDC interconnection and electricity-gas-heat coupling

To promote inter-regional resource complementarity and improve the level of new energy consumption， a collaborative optimal scheduling model for coupled transmission and distribution systems considering DC tie-line power adjustment and electricity-gas-heat coupling is proposed. Firstly， a power adjustment model of DC tie-line is established to make full use of the adjustment capacity of the tie-line to improve the operation flexibility of the system. Secondly， an active distribution network model considering the electricity-gas-heat coupling is established for the receiving-end grid. Moreover， the coordinated optimization of the HVDC tie-line and the multi-energy complementary system of receiving-end is carried out. The linearized AC power flow is used for approximate calculation of the distribution network loss， and nonconvexity the Weymouth equation of natural gas pipeline flow is incrementally linearized. In so doing， the model in this paper is transformed into a mixed-integer linear programming （MIP） problem. Finally， an example is given to verify the effectiveness of the proposed model and method.