Research On Impact Of Dispersed Wind Farm On Voltage Stability Of Distribution Network

With the continuous development of large-scale centralized wind farm, the issue of windpower transmission has become increasingly prominent. At the same time, it has brought newchallenges to the safe and stable operation of power system. Under these conditions, thedevelopment of low wind speed but near to the distribution network wind farms becomes aninevitable trend. However the wind power multi-connected to the distribution networkchanged one-way power flow of distribution grid system, brought great influence to thevoltage stability of the network. With increase of wind power permeability in distributionnetwork, the reactive voltage control problem of dispersed wind farm will become moreprominent. This thesis studied the voltage stability of the distribution network with dispersedwind farm connnected under different positions of access point, access capacity, and windgenerators control mode.Firstly, the mathematical model of the doubly-fed induction generator(DFIG) wasestablished, the reactive power characteristics of DFIG under the condition connected todistribution network was analyzed, the feasibility of reactive voltage control based ondispersed wind farm,s own reactive power was proved which laid the foundation for futurestudy.Secondly, aiming at dispersed wind farm connected to distribution network, thedistribution network voltage stability index is deduced. Through the case simulation, thedispersed wind farm impact on voltage stability of the point of coupling (POI) under thecondition of different access point, different access capacity and different operation conditionwas analyzed.Finally, on the basis of the above study, a multi-objective and multi-constraint reactivevoltage control algorithm was proposed under different time scales, voltage stability of eachcoupling point was achived by the overall optimization.