Generation Planning Of Distribution Network Considering Admissible Region And Efficient Calculation Of Reliability Cost

The generation planning of distribution network can carry out reasonable location and capacity determination of power supply in different regions,which is of great significance in ensuring the safety,reliability and economic operation of distribution network.With continuous adjustment of the energy structure in our country,power generation resources such as distributed power sources,energy storage and electric vehicles become increasingly popular,and the proportion of renewable energy is increasing.The high uncertainty of source-load brought seriously affected the result of generation planning in distribution network.Therefore,this paper takes the generation planning of distribution network as the research object and carries out an in-depth study on the generation planning of distribution network with a high proportion of renewable energy access.Firstly,the node admissible region is introduced into the distribution network planning model,and the system’s acceptability of renewable energy is directly reflected from the adjustable resource node to the load disturbance node,and a distribution network power planning model considering the optimal admissible region of net load is established.Based on the above proposed model,a generation planning model of distribution network considering both net load uncertainty and price uncertainty is constructed by expanding the uncertainty object;a generation planning model of distribution network considering multiple reliability indexes is constructed by expanding the reliability index object.The nonlinear reliability cost expression with integral characteristics in the model is linearized,and the constraints are processed by means of duality theory and alternate iteration.Finally,the model is transformed into a mixed integer linear programming model,and it is verified by an example based on the improved IEEE 33 node distribution network.Nextly,it is found that reliability index calculation is the bottleneck of the whole planning problem.In the traditional linearization process of reliability index,0/1 variable is introduced for piecewise positioning.The more the number of segments,the more accurate the linearization result will be,but the more 0/1 variable is introduced.In addition,with the number of net load nodes increasing,the number of 0/1 variables also increases rapidly,thus affecting the computational efficiency of the model.In order to solve the above problems,the mathematical characteristics of traditional reliability cost function are fully explored,and two new reliability index calculation methods,the constrained cost variable method and the step superposition method,are proposed in this paper.The new methods do not contain 0/1 variable in the calculation formula,which significantly simplifies the model and is conducive to improving the calculation efficiency.Based on an IEEE 33 node distribution network example,it is verified that the new reliability costing method not only has better accuracy,but also effectively improves the solving efficiency of the model.Finally,based on stochastic optimization method and robust optimization method respectively,a distribution network planning model based on scenario calculation reliability cost and a distribution network planning model based on interval calculation reliability cost are established.According to the characteristics of cost/benefit compromise optimization method,the interlinked nature between the models is analyzed.The quantitative verification is carried out based on the IEEE 33 node distribution network example.The results show that,when the number of discrete scenarios and the number of interval segments is large,the scenario based planning model and the interval based planning model have the same results,and the interlinked nature between the scenario based and interval based model is verified.