Regional Spot Market Clearing Model for Multi-terminal High Voltage Direct Current Tie- Line with Bidirectional Transmission

China's resources and load centers are distributed in reverse, and high voltage direct current (HVDC) technology is utilized to optimize the allocation of resources in the maximum range. Multi-terminal HVDC power can be freely controlled, and its characteristics of bidirectional transmission, network losses in the transmission process, power transmission restrictions, and power change restrictions in adjacent periods bring challenges to the spot market clearing model in the new power system environment. So, this paper proposes a HVDC tie-line model considering the characteristics including bidirectional transmission and transmission network loss. On this basis, this paper further proposes a regional spot market clearing model that also considers the transmission price of the tie-line in the spot market. With the goal of minimizing the overall cost of the region, the DC tie-line power, unit on and off state, and unit power are used as decision variables in the proposed model, and integer and nonnegative continuous variables are introduced to optimize and determine the tie-line transmission direction. Then the DC tie-line transmission power schedule, the AC tie-line transmission power schedule, unit start-up and shutdown schedule, and unit power schedule of the regional power grid are obtained on the premise of ensuring the security of the regional power grid. The proposed model finally realizes the synergy of wind, solar, water, and fire resources in the region. The three-region IEEE RTS-96 system is used for calculation, and the results verify the validity of the proposed model.