Research On The Impact And Enhancement Method Of Voltage Quality In Distribution Network With Wind Generator

Because of the high randomness,the influence of wind energy on voltage quality is becoming more and more obviously with the rapid development of wind generator in China.The develop speed of wind generator will be limited while the voltage quality problem leaving unsolved.In the beginning of this paper,the configuration of wind generator system is introduced,which will lead to a series of voltage quality problems with wind randomness.The origin and harm of voltage quality caused by wind generator,such as voltage divination,harmonic,voltage sag and fluctuation is analyzed.The influence and solution of each voltage quality are discussed later,and the voltage quality compensation model is mainly discussed.Because of the duration time of voltage divination study,the power model of wind generator during one typical day is discussed for calculating the power flow of real distribution network,which reflect the wind influence on voltage divination.Large amount of penetrating wind generators may cause the voltage out of limit,which will restrict the improvement of wind energy.The harmonic level is related with wind turbine property.Thus,the harmonic caused by wind generator is studied with the calculation of maximum penetration capacity.The calculation is based on the multiple constraints.Lots of DG penetrating situations are calculated on a real 10 kV distribution network.The results are evaluated by entropy method considering the value of maximum penetrating capacity and harmonic level,which indicates the relationship of harmonic and DG configuration.The results will make sense while planning generator locations,in order to reduce the harmonic percentage.Voltage sag and fluctuation are caused by the variation of wind speed.In this paper,a period of wind speed in 1 minute is forecasted by ARMA model,which lead to a simulation of the voltage sag and fluctuation caused by wind generation.The voltage problems simulated with the forecasted wind speed are deal with the voltage quality compensation model,which is built according to the voltage problem during the in-grid process.The model based on super-capacity and battery storage,is consisting of AC converter,DC converter,power calculating,PWM control and other control modules.The efficient of the voltage quality compensation model is studied on PSCAD/EMTDC with the wind variation data obtained before.With the simulation result,an energy storage configuration calculating method is proposed,in order to choosing the storage capacity needed,which can improve the economic and safety of the voltage quality compensation model.The research in the paper is based on power flow calculating,maximum penetrating level and voltage quality compensation model.It has a benefit to the development of wind generator in distribution network.