| Energy and environment problem become more and more serious because of the rapiddevelopment of modern industry and the increasing depletion of fossil fuels, as a renewableenergy, wind power becomes the fastest growing renewable energy of the world. Because therandom, intermittent and uncontrollable nature of wind power, its impact to the system relayprotection becomes more serious as its capacity becomes higher. According to the problemduring grid dispatch and operation, following issues will be analyzed in this thesis:This paper introduced the basic structure and the operating principle of DFIG,then,adetailed mathematical model of the doubly-fed units is derived based on the vector controltechnology,furtherly,the control strategy of the the rotor side and grid side power converter areestablished.then,then build a simulation model on the PSCAD platform,with the twoconditions of wind speed fluctuations and power grid failures, the system steady state andtransient operating characteristics is detailed analysis.The impact to grid voltage deviation after the injection of wind power andcountermeasure is analyzed, the injection of high-capacity wind power will affect powerquality of the grid because the random, intermittent and uncontrollable nature of wind power,its impact to grid voltage deviation become most obvious because reactive power absorptionof the wind power farm. The installation of reactive compensation device on the wind powerfarm is the most economic method to solve such problem according to the reactive localcompensation rule. In order to confirm the reactive power compensation capacity, this paperpresents an adaptability reactive optimization model which is able to adapt to changes in windpower.Adynamic model of the doubly-fed wind power system was build based on PSCAD, andthe impact on the way and the action time of line reclosing was studied. At last, a number ofrecommendations were put forward for the12th Five-Year Plan of the regional power grid. |
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