Siting And Sizing Selection Of Distributed Generation Considering Uncertainty

Distributed Generation(DG)refers to a small,modular,and inde pendent power source with power generation ranging from several kilowatts to 50 MW.The power generation mode of DG is environmentally friendly,DG is developing rapidly,nowadays.The connection of DG to grid changes the structure of the original distribution network.The site and size of DGs connected to the grid affects the operation status of the distribution network,directly.If the DGs is connected to the gird reasonably,it will improve the reliability of the distribution network power supplying,improve network node voltage levels and reduces system network losses.Therefore,the problem of DGs connecting to the grid reasonably has become a research hotspot in recent years.This paper focuses on the research of optimizing method of DGs connecting to the grid.The effects of DGs grid-connected on the distribution network are analyzed from four aspects: power supply reliability,relay protection,node voltage level and network loss.The impact of DGs on the distribution network is related to site and size of DGs connecting to the grid.Intelligent algorithms are often used to solve the problem of selection of DGs site and size,it needs to manually set optimization parameters,but the optimization parameters are not scientifically calculated,often bas ed on experience.Therefore,there is a problem that the optimization result is inaccurate due to the inaccuracy of the optimization parameter setting;the setting of the optimization parameter is obviously subjective,which lead to the optimization result is subjectivity and randomness.Aiming at the above shortcomings of the existing optimization methods,the DGs grid-connected optimization method based on marginal utility is proposed in this paper.The method is to calculate the marginal utility of the o bjective function brought about by the DGs per unit size to determine the optimal site and s size of the DGs connecting to the grid.The proposed method does not need to set optimization parameters,which ensures the objectivity and accuracy of the calcula tion results.Simulation results verify the rationality of the proposed method.Aiming at the uncertainties in the actual distribution network and the volatility of DGs output,a DGs site and size planning method based on marginal utility and probabilistic power flow is proposed.This proposed method can select the connecting site and size of DGs to the grid properly considers the uncertainties in the distribution network,which is more practical.In the simulation calculation,It shows via the simulation that Comparing with the optimization results using the improved genetic algorithm optimization method,the proposed method can improve the expectation value of node voltage better,and the node voltage in the network has a lower probability of exceeding the limit.So the optimization result is better by the proposed method.