Research On Smart Distribution Network Planning With Micro-Grids

With the rapid development of renewable energy and the demand for the development of resource-saving and environment-friendly society in our country,more and more distributed generations and micro-grids are connected to the distribution systems,which has become an important part of the smart distribution network,providing clean energy,replacing part of the power supply demand in distribution network,and improving the overall reliability and flexibility of the distribution network.But it also has an important impact on the planning and operation of the distribution network,increasing the difficulty and uncertainty of planning and operation.With the increase of micro-grids permeability,it is necessary to study the new method of smart distribution network planning with micro-grids,analyze the influence of distribution network substation planning,network frame planning and expansion planning with micro-grids,and determine the reasonable location and capacity of micro-grids.Starting from the power characteristics of new types of power source and load,firstly,this paper discusses the influence of micro-grids joining on load forecasting,power source planning,network frame planning,power quality,relay protection,dispatching operation and network loss,and studies the hot wind-PV system,energy storage system and charging stations according to the typical structure of modern micro-grid.On the basis of which,the equivalent model of micro-grid is established,and Monte Carlo method is used to simulate the randomness of the power characteristics of micro-grids.Then,the model of the distribution substation planning with micro-grids is established,and the multi sources successive locating method is used to solve the problem.At the same time,a model of the distribution network frame planning with micro-grids is established,and the power flow calculation is solved by using forward and backward substitution method.The genetic-simulated annealing algorithm is used to solve the planning model.The feasibility and advantages of the planning model and the planning method are verified by a typical distribution network planning example.Finally,we focus on the distribution network expansion planning model with micro-grids,and use bi-level programming theory to solve the model.The minimum tree generation method is used to solve the upper-level planning model,problem of network frame planning.The genetic-simulated annealing algorithm is used to solve the lower-level planning model,problem of location and capacity problems of MG and EV.It not only simplifies the difficulty of solving the problem and avoids the "the curse of dimensionality",but also is better than solving separately.Through analysis of examples,the feasibility of the model and algorithm is verified.