Influence Of DG On Feeder Power Supply Ability And Its Optimal Configuration In The Planning Of Distribution Network

In order to cope with the problem of environmental pollution and energy depletion,it is urgent for mankind to develop clean and renewable energy to maintain the sustainable development of society.On account of the power flow and the feeder power supply capacity are related to the economic operation of distribution network,with the large number of distributed generators?DG?connected to the distribution network,not only the power flow of system has changed greatly,but also made a certain impact on the maximum power supply capacity of the feeder.There have been many studies on the influence of DG access on the power flow of distribution network,while the research on the influence of DG connection on the feeder power supply capacity is relatively scarce,in order to make the distribution network operate more economically,the above problems need to be evaluated.What's more,the output of DG is generally stochastic and intermittent,when it is connected to the grid with different locations,capacities and types,it will affect the safe and stable operation of the power system to varying degrees.Grid planners must consider the impact of capacity,type and location when choosing the optimal DG access scheme to make sure the power grid operates more safety,stability,reliabity and effiency.Aiming at the above problems after DG access,this paper firstly studies the system power flow under four typical node types of DG access based on implicit Z_bus-Gauss method,analyzes the influence of different location and permeability access on system loss and node voltage,and compares the errors when all kinds of nodes are equivalent to PQ nodes.Secondly,the calculation method of DG's credit capacity?CC?is redefined from the point of view of distribution network by taking grid fault into account in this paper,and a method based on the perspective of CC to evaluate the impact of DG access to distribution network on feeder power supply capacity?FPSC?is proposed.In the specific example,the influence of the feeder load,the output correlation of source and load,the position and capacity of DG on the FPSC is analyzed.Finally,considering the FPSC of distribution network,a mathematic model of location and sizing of DG in distribution network planning is proposed.Based on the improved RBTS BUS6system,the location,type and capacity of the distributed generation are taken as the solving objects,and the minimum network loss,the minimum sum of voltage deviation and the maximum power supply capacity of the feeder are taken as the optimization objectives,the adaptive multi-population genetic algorithm is used to solve the mathematical model.The optimal configuration results show that the loss and voltage deviation of the distribution network are greatly reduced when the distributed generation is located at the end of the line,but the improvement of the FPSC is limited when the capacity is limited and the energy storage is not configured.By comparing the subobjects values before and after DG accesses,it also shows that it is necessary step to optimize the location and capacity of distributed generation in distribution network planning in order to run the distribution network more efficiently and economically at the same time,planners need to take into account the relevant impact.