Research On Transmission Network Expansion Planning Method For New Power System

The continuous promotion of the construction of new power systems has gradually improved the level of low-carbon and clean power generation on the power supply side.A high proportion of new energy power generation access systems will make the coordination and control of the transmission network more complex,bringing new challenges to the safe operation of the power system.Transmission network expansion planning optimizes the construction of future transmission networks based on load forecasting and power planning in the future planning cycle.During the planning process,multiple influencing factors can be integrated to coordinate and restrict each other to achieve optimal planning and operation results.Therefore,it is of great significance to improve the system’s ability to accept new energy for power generation by setting reasonable grid planning schemes.This paper mainly focuses on the research of output volatility,consumption demand,and short-circuit current exceeding limits brought by large-scale access of new energy,such as wind power,to power systems.Firstly,it analyzes the influencing factors of power grid planning and introduces the theoretical basis for scenario clustering,short circuit current calculation,and model establishment and solution of power grid planning.In order to quantify the contribution of wind turbines in short-circuit current calculation,an equivalent model of wind turbines is proposed through structural equivalence of wind farm power collection systems.To address the uncertainty of wind power output,an improved adaptive k-means algorithm is proposed to cluster typical wind power output and load scenarios.Based on this,a planning level solution is proposed:selecting to allocate energy storage at wind power consolidation sites to address the issue of wind power output volatility;In the power grid expansion planning model,the impact of energy storage and demand side response is comprehensively considered,and both the generator unit and the active output of energy storage are treated as state variables,enabling the coordination and optimization of source network load storage,and solving the complex problems of consumption demand and operation;From the perspective of conventional thermal power unit startup and shutdown caused by system load changes,the short circuit current constraints in typical scenarios are transformed into constraints corresponding to the startup and shutdown status of the unit,and a short circuit current constraint considering line optimization switching current limit is introduced to solve the operation problem of short circuit current exceeding the limit.Then,with the goal of minimizing the cost of new lines,investment costs of energy storage systems,wind farm abandonment costs,demand side response compensation costs,and switching line costs,a wind power grid expansion planning model is established that comprehensively considers energy storage,demand side response,and line optimization switching and current limiting.GUROBI is invoked on the MATLAB platform to solve the problem.Finally,a numerical example is analyzed and compared with different cases.The conclusion is drawn that considering the startup and shutdown status of the unit to limit the current of the switching line can minimize the overall planning cost under the conditions of satisfying safe operation.The methods and models proposed in this paper are effective;A reasonable planning model can take into account new lines,wind power consumption,and safe operation.It can provide grid and energy storage capacity planning results while achieving optimal scheduling and grid optimization in typical scenarios,enabling the source-network-load-storage processes to work together to promote optimal planning results.