Research On Planning Method Of AC-DC Hybrid Power Grid

At present,China’s power grid construction is in a period of rapid development.Due to the reverse distribution characteristics of resource rich areas and load center areas in China,the power supply and demand network will need large-scale power transmission of "west east power transmission" and "North South Power Transmission" for a long time to ensure the balance of power supply and demand.Due to the advantages of large transmission capacity,low transmission cost and long transmission distance,UHVDC transmission system will be built in China from 2020 to 2030 to meet the power demand of the receiving area.As a result,East China,central China and other load areas have gradually evolved into a multi DC / AC feed into the receiving power grid,the proportion of external receiving power has increased,and the security and stability characteristics are facing new challenges.Therefore,how to fully consider the interaction between DC project and AC power grid in the power grid planning stage and build a strong and reasonable AC-DC hybrid power grid is a long-term problem that needs to be focused on in China’s current and future power system planning work.After analyzing the key factors of AC and DC receiving power grid planning,this paper studies the AC and DC receiving power grid planning in three cases.Firstly,aiming at the planning of AC / DC power grid with only AC line expansion,considering the constraints of adding DC loop constraint and DC system safety constraint in the traditional planning of AC / DC power grid with only DC line expansion,the planning model of AC / DC power grid with DC line expansion is constructed,and the planning model of AC / DC power grid with DC line expansion is analyzed through specific examples The impact of the stroke.Secondly,for the AC / DC receiving end power grid planning determined by the type of extended lines,the benders decomposition algorithm is used to divide the AC / DC line expansion planning into two sub problems for hierarchical optimization,and the influence of system parameters such as installed capacity,electric load and thermal load on the wind power consumption level of the system is analyzed.Finally,in order to solve the problem of AC / DC receiving end grid planning with mutual exclusion constraints,CSP(constraint satisfaction)is considered Problem(CSP)formalization is used to study the impact of mutually exclusive constraints on the planning of AC and DC power grid.Based on the above research,the corresponding planning model is established,and the feasibility of CSP formalization is verified by a specific example.