Distribution Network Risk Assessment Research Considering The Impact Of Wind Power And Electric Vehicle

In recent years, with China’s strong and smart grid construction continuously pushforward the implementation of the policy as well as energy saving, new energytechnologies become an important trend for the development of power system, windpower and electric vehicles has been the strong support of the national development of thepower industry. However, with more and more widespread application of wind power andelectric vehicles, and the negative impact to the power system can not be ignored. Naturalfluctuation characteristics of wind energy itself is random, intermittent and uncontrollablecreating wind power, wind power and the growing scale of the network on the grid interms of a random perturbation also increases the reliability and security of the power grid,bring The threat is also growing. Electric vehicle by the user vehicles used as well asenvironmental impact, making the electric vehicle as the charging load on the uncertaintyof the time and space, the access distribution network of the electric vehicle will likelylead to the grid during periods of peak load is increased, so that the grid operationbecomes complicated. From the point of view of the urban distribution network, alarge-scale wind power and electric vehicles access is a great opportunity to promote thedevelopment of the grid tends efficient, clean and intelligent, and more severe challenges,the study wind power and electric vehicle charging behavior uncertainty of the impact ofthe power system, to reduce the threat posed by wind power and electric vehicles and theGrid will improve grid reliability and security, and has a very important theoretical andpractical significance.For wind power and electric vehicles and the network of the impact of thedistribution network, the main analysis and grid node voltage and line flow two aspects ofrisk. First, using a three-parameter Weibull distribution describe the randomness of thewind speed, combined with the characteristics of the power output of the wind turbine andwind turbine-based internal simplified equivalent circuit the PQ iterative model to buildwind turbine active and reactive probability distribution model. The same time, the dailymileage is assumed that the electric car, traveling end time follow a normal distribution,thereby establishing a statistical model of the discharge power for electric vehicles. Basedsemi-variable power system random flow calculation method, the use of stochasticmathematics in the calculation of the mathematical basis of the method, considering thewind farm output variation, uncertainty electric vehicle charging load fluctuations andrandom generator outage factors, according to the each injection powersemi-semi-invariant variables obtained state variable (bus voltage) and output variables(branch power) random variables, to strike a random variable by Gram-Charlier series expansion approach, and the Von Mises method The successive portions of the probabilitydistribution and the probability values and probabilities of the various points of thediscrete part, and finally get node voltages and branch power distribution. Finally, the useof risk theory, were established taking into account the wind power and the voltage of theelectric car is more limited and the risk indicators of the branch circuit overload,quantitative assessment of wind power and electric vehicles access with network risk. As acase study, the IEEE33-bus system were simulated for analyzing impact of wind power、electric vehicles alone access and both access on system risk with using the proposedmethod. The access scenario of wind power with different capacity, the electric vehiclewith different penetration, as well as both of wind power and electric vehicle withdifferent times, are calculated the risk level of the state of the current system is running,which provided an important theoretical and practical significance for the rationalplanning of wind power and electric vehicle.