Research On Transmission Network Expansion Planning Considering Spatially Differentiated Demand Response

Under the context of "carbon peaking and carbon neutrality goals",the proportion of installed wind and solar power capacity and the amount of wind and solar power generation in our country will be further increased.Meanwhile,the increasing level of electrification leads to a higher proportion of new types of loads,and the peak loads increases year by year.The strong uncertainty and weak controllability brought by new energy will become more severe.The purpose of transmission grid expansion planning is to expand the original power grid lines after matching the installed power capacity with the demand for loads,in order to meet the demand for power transmission and comply with the N-1 principle.Due to the increased fluctuation of new energy output and load,in high peak load scenarios,there may be local flow congestion after N-1 faults occur.Traditional methods of transmission grid expansion planning may be difficult to meet both economic and adequacy requirements simultaneously.A great abundance will lead to a poor economy.This paper proposes a transmission grid expansion planning method that considers spatial differentiation of demand response,which not only improves the economic and adequacy requirements of transmission grid planning,but also formulates time-of-use pricing plans with spatial differentiation,targeting the local congestion issues in the power grid under N-1 faults.The main research content of this paper is as follows:Firstly,the applicability and characteristics of two commonly used methods in transmission grid planning,namely evaluation decision-making and mathematical optimization,are analyzed.The application methods and research results of demand response in transmission grid planning are summarized,and the advantages and disadvantages of solving methods for transmission grid planning models are compared.This clarifies the planning ideas of this article.Secondly,the response potential of different types of demand response users is analyzed from multiple aspects such as response scale,response behavioral characteristics,and actual application situations.The types of users that are suitable for consideration in transmission grid planning under the current background are summarized.Optimization models for demand response of electric heating users and large industrial users under time-of-use pricing mechanisms are established.Users can adjust their response curves based on the time-of-use pricing plan.This lays the foundation for the subsequent studies.Then,a two-layer model for transmission grid planning is proposed,taking into account spatial differentiation demand response and N-1 constraints,to study the transmission grid expansion planning scheme with the objective of minimizing the sum of transmission grid planning cost and demand response cost,as well as the spatially differentiated time-of-use pricing optimization scheme.Given the characteristics and computational difficulty of the established model,the Kuhn-Tucker conditions are used in this paper to convert the lower-level model into constraints of the upper-level model,and the Big-M method is adopted to linearize nonlinear constraints.Finally,the transformed model is solved using commercial solvers GUROBI and YALMIP toolbox in Matlab 2021a.The case analysis shows that considering demand response in transmission grid planning can adjust the load curve in the long term,reduce system planning costs,and adjust the local congestion problems of the power grid in a targeted manner,providing reference for power grid companies to develop time-of-use pricing plans in the future.