Studies On Wind Power Accommodation Capability And Co-planning Of Generation And Transmission Considering Branches Switching Control

With the integration scale of wind power increasing in the power system,the large-scale integration of wind power has an adverse impact on the safe and stable operation of the system,although the problems of energy resources shortage and ecological environment deterioration could be alleviated.Due to the randomness and intermittent of the wind power,the scale of wind power access to power systems is generally limited,and the acceptance capacity of wind power in system will be even reduced when congestion occurs.The adjustment of power grid structure is an important method to optimize the power flow distribution of power system,and the influence on the wind power acceptance capacity of the power system by changing the network topology structure can not be ignored.Therefore,it is of great theoretical significance and practical significance to study the wind power accommodation capability of power system and the coordinated planning of wind power-transmission network considering grid structure adjustment.The main research contents are as follows:(1)The power grid structure usually was considered as changeless in existing wind power accommodation capability calculation methods,which neglected the influence on the power flow distribution of power system by adjusting the power grid structure.For this problem,firstly this paper analyses the influence mechanism of branches switching on the power flow distribution and the wind power accommodation capability of power grid based on the sensibility method.Then the Latin Hypercube Sampling and k-means clustering method is used to deal with the randomness of wind speed and load to form the multi-scenarios set,and the optimization model with the objective of maximizing total installed capacity of wind power accommodated by power system is established,the switching branches are set as controlled variable and the unbalanced power allocation in every scenario is considered in the model,the Adaptive Genetic Algorithm is used to solve the proposed model.At last,the IEEE 39-bus system is taken as a case to verify the feasibility and effectiveness of the proposed model.The results show that considering branches switching control of the power grid can improve the wind power accommodation capability of power system.(2)The influence of network topology structure adjustment on the wind power accommodation capability of power system hasn't been considered in existing plannning methods of transmission expansion and wind power installed capacity.For this problem,a co-plannning method of transmission expansion and wind power installed capacity is studied in this paper,and the branches switching control is introduced in this method.Based on the bi-level programming model,the weighted calculation of the investment cost of new transmission lines,the wind farm revenue and the generators' operating cost is set as the objective to form the upper-level wind power installed capacity and transmission expansion planning model for economic purposes of the planning scheme;based on the upper-level planning grid,the lower-level model is built with the objectve of maximum installed capacity of wind power considering transmission switching control.The Adaptive Genetic Algorithm and interior point method are used to solve the optimization model.The IEEE RTS24-bus system is taken as a case to verify the feasibility and effectiveness of the proposed method.The results show that the wind power accommodation capability of the planning network and the net income of wind farms can be improved considering branches switching control in the co-planning of wind power installation capacity and transmission network explansion.