Due　to　the　influence　of　natural　factors,　the　output　power　of　wind　farm　is　fluctuant　and　random.　This　would　cause　voltage　drop　variation　on　the　line,　and　then　lead　to　node　voltage　fluctuation　and　affect　the　power　quality　of　public　network.　Advanced　power　quality　analysers　can　measure　the　voltage　fluctuation　severity　accurately,　but　it　couldn＇t　be　used　for　pre-evaluation.　Build　a　relational　model　between　natural　factors　and　wind　power　to　predict　the　output　power　of　wind　turbine,　and　then　pre-estimate　the　voltage　fluctuation　by　interval　arithmetic.