The Impact Of Wind Power Integration On Power System

In the past of hundreds of years,the fossil energy reserves like coal,petroleum and natural gas which are non-renewable energy fell sharply due to the abusing by people.The energy crisis and environmental degradation in human society have forced government to develop new energy sources to meet higher demand for living production.As the most mature one in the new energy power generation technology,wind power generation technology has a certain impact on the dynamic behavior and stability mechanism of the power system due to the increasing capacity of wind power generation connected to the power system.Frequent small disturbances will not only affect the stability of the system,but also cause huge economic losses.In order to gain deeper understand of the impact of wind turbine access on power system stability,it is necessary to do grid-connected simulation of wind turbine and analyze its impact on system stability.Based on PSAT,the power system software analysis package on matlab,this paper integrates different types of wind turbines into the power grid for small-interference stability analysis,analyzes the influence of wind farm on small-interference stability of power system,and integrates two kinds of reactive power compensation devices into the power grid for time-domain simulation to compare their impact on voltage stability of power system.The main contents of this paper are divided into three aspects as following:Firstly,the analysis method of small disturbance stability and the analysis method of small disturbance stability in power system software package are systematically expounded.Then,the mathematical model of wind turbine is established from two aspects: On the one hand,the mathematical model of electric system includes wind speed model,squirrel cage induction wind turbine model,doubly fed induction wind turbine model and direct drive permanent magnet synchronization.The wind turbine model,on the other hand,is the mathematical model of mechanical system,including the wind turbine aerodynamic model,the wind turbine drive chain model and the pitch angle control model,which lays a theoretical foundation for the following experimental simulation.Secondly,three different types of wind turbines are incorporated into the standard 3-machine 9-node example of the Western United Power System(WSCC).The eigenvalue analysis method in PSAT is used to study the influence of wind turbines on the stability of the small disturbance when accessing the system with different access nodes,types,wind farm access distances,different wind power penetration rates and wind power parameters.The results show that the above several conditions will have different degrees of impact on the system and the influence of doubly fed induction wind turbines on the small interference stability of power system is better than that of the other two.The closer the wind turbines are,the lower the permeability of wind power and the better the small interference stability of the system is when the wind turbines are determined.Finally,on the basis of IEEE standard example of 5 generators and 14 nodes,two different kinds of reactive power compensators,Static Var Compensator(SVC)and Static Synchronous Compensator(STATCOM),are connected.The time domain simulation method in PSAT is used to study the wind speed of doubly-fed induction wind turbines in parallel mode replaced by outage.The influence of reactive power compensation device on improving system stability under three conditions: change,three-phase short-circuit fault and sudden load disturbance.The results show that the stability of STATCOM is better than that of SVC under the above three disturbances.