With　the　ever-increasing　penetration　level　of　wind　power,　its　impacts　on　power　system　reliability　and　power　quality　are　becoming　more　and　more　significant　mainly　due　to　the　randomness　and　uncertainty　of　wind　resource.　For　accurate　express　of　the　model　about　input　wind　speed　of　wind　turbines,　some　influence　factors　of　wind　speed　will　be　considered　as　noise　variables,　and　then　a　model　about　the　uncertainty　of　input　wind　speed　in　wind　farms　will　be　set　up　by　affine　arithmetic　method.　So　the　output　power　affine　model　of　wind　turbines　can　be　calculated　from　the　model　above,　attaching　the　requirements　of　power　factor　by　the　state　grid,　it＇s　easy　to　gain　the　reactive　power　affine　model.　Thereupon,　with　the　relative　parts　of　voltage　fluctuation,　SVG　capacity　in　wind　farms　can　be　reasonably　optimizing　and　analyzing　after　knowing　the　reactive　power　compensation.