The Impact Of Wind Power On Load Characteristic And Its General Comprehensive Load Modeling

The power system simulation is the decisive basis for the power system planningand analysis, which are directly related to security and stability of power system.Because the randomicity, time-variant and diversified nature of power load, it isdifficult to establish precise load model.With the further research on all kinds ofrenewable clearer energy, the distributed generating source(DGS) capacity connectedto system increases day by day. As to various mechanism characteristics of DGs, therewill be a great change in the traditional topology of distribution network and regionalload composition and characteristics, which would bring great difficulty to the loadmodeling. Wind energy is a typical kind of renewable energy and the distributed windpower is the fastest growing,the largest distributed power grid capacity up to now.Thedistribution network load modeling considering the distributed wind power hasbecome a hot research spot in the current power system analysis and control field,whose study has vital theoretical and practical significance.The directly driven wind turbine with permanent magnet synchronous Generator(D-PMSG) is a typical wind power generators type. After deepin-depth study on themechanism and the structure characteristics, operation principle and grid controlstrategy, the paper researched the mathematics model of each module and simulationmethod of the D-PMSG power generation system. On the basis ofMatlab/Simpowersystem toolbox, the detailed digital simulation system of theD-PMSG power generation is constructed. With digital simulation method, thedynamic operation characteristics of the D-PMSG operating under the steady-stateand the grid disturbance has been simulation studied and theoretical analysisd. TheD-PMSG can be equally seen as a generalized dynamic load with negative powerconsumption.its operation principle, the modules mathematical model, characteristicsand control methods. After analyzing the dynamic operating characteristics throughsimulation, the D-PMSG can be equally seen as a generalized dynamic load withnegative power consumption. Consequently, the mechanical and electrical transientequivalent model of third order differential equations of state description equivalentmodel was presented. Through identifying the parameter of in different degree of faultdigital simulation, the results have validated the model could fit the Mechanical andelectrical transient characteristicsdynamic external characteristics. In the basis of the research on the D-PMSG and through deep analyzing the theinfluencing characteristics and regularity of the comprehensive load characteristicswhen the wind turbine access to the network, A generalized comprehensive loadmodel is promoted, which can be obtained by adding the load model of the D-PMSGto the virtual bus of traditional synthesis load model. Through validating andidentifying the comprehensive load model using the sample of the transient simulationunder different load proportion, the results have shown the good describing ability ofsynthesis load model.In order to quantitatively analyze the influence of the area load characteristicswhen distributed wind power accessed, the evaluation index of “comprehensiveresidual”and”similarity differences impact factor” is raised in the paper, which realizeto evaluate the influence degree of comprehensive load characteristics under differentfactors. The results of the study have demonstrated that, the farther the distancebetween wind turbine and the equivalent load bus, the smaller the impact on loadcharacteristic. Besides, as the wind power capacity accessed increasing, the amplitudeof the transient power transforms obviously, and recovery time is long after the faultresection.