Study On Impact Of Grid-Connected Large Wind Farms On Power System

Attempts to reduce dependency on fossil fuel resources and increasingly global warming are bringing concerns on renewable energy resources. Among the various renewable resources, wind power is assumed to have the most favorable technical and economical prospects. At the same time of providing clean energy for the grid, wind power brings some negative effects. This paper discusses the impact of grid-connected wind farms on transient and small signal stability of power system.The simulating tool——PSS/E and its general models of wind turbine generators are firstly introduced. The models are WT1, WT2, WT3 and WT4, which are based separately on direct connected conventional induction generator, wound rotor induction generator with variable rotor resistance, doubly-fed induction generator and full size converter.The following chapter discusses the impact of grid-connected wind farm on transient stability of power system. How to equivalence a wind power plant collector system and which node type should wind farm be regarded are described. The transient characteristics of power system with different types of wind power plant are compared to show the impact of grid-connected wind farm on transient stability of power system. A study is made to verify the role that dynamic reactive compensation devices installed near wind farms play on improving transient stability of power system with wind power.Lastly, the impact of grid-connected wind farm on small signal stability of power system is discussed. The physical mechanism that grid-connected wind farms based on fixed-speed induction generation provide a positive contribution to small signal stability of power system is revealed. Methods of small signal stability analysis considering grid-connected wind farms using eigenvalue analysis and Prony analysis are illustrated through a test example. At last, two factors, which are the type and capacity of wind farms that influence the small signal stability of power system with wind farms are given.