More and more large capacity wind power will be integrated into power system in the future，and certaintechnical challenges will emerge due to the fluctuation characteristics of wind power and the complex control ofpower electronic devices inside the wind turbines（e.g.，low voltage ride through（LVRT））.By comparing a windpower integration grid with a hydropower integration grid，the special transient phenomena caused by the windpower integration is studied and simulation results are presented.Furthermore，the potential impacts on thetraditional protection are discussed.Results show that the special transient phenomena can decrease the sensitivity， reliability and operation speed of conventional protections.