Research On SSSC Control Strategy Optimization Based On Grid Connection Of Wind Power Generation

With the exhaustion of traditional fossil energy and the energy challenge brought by the rapid development of economy,the development and utilization of renewable energy has become an important part of energy strategy.Wind power generation,as a renewable energy utilization method with great potential and good prospects,has been developing rapidly in China in recent years.By December 2019,the cumulative installed capacity of wind power in China has reached 21,0050 mw.However,with the increasing penetration rate of wind power generation and other distributed power sources in the power grid,their own output is unstable due to the change of external environment,which poses new challenges to the stability and power quality of the distribution network.Static synchronous series compensator(SSSC)is a kind of static compensation equipment in series on the transmission line.Its installation point is flexible,dynamic performance is good,strong adaptability,can be equipped with a variety of types of controllers,is an important ac transmission device to realize the damping system power oscillation.It can quickly adjust the active power and reactive power of the line,but also has the advantage of simple structure,compared with other compensation equipment,it has the advantages of smaller area and less investment.In this paper,an optimal additional damping control strategy based on grey Wolf optimization algorithm is designed for SSSC,aiming at realizing the system power Angle and power oscillation instability under the working conditions of wind speed change and short circuit fault.In this paper,the structure of DFIG is briefly described,the mathematical model is established,and the basic control method and grid-connected control system are analyzed.MATLAB/SIMULINK is used to design the simulation of the working condition of wind speed change and remote fault when DFIG is connected to the grid,and the influence on the stability of the power system is analyzed.It is concluded that SSSC equipment is needed to realize power optimization and damping oscillation to improve the system stability.After studying the basic topological structure of SSSC and mathematical model on the basis of the analysis of the operation mode of the SSSC and 3 kinds of state compensation,through mapping Angle under different amplitude compensation voltage characteristic curve,deeply discusses the SSSC at work has a controllable amplitude and phase Angle of the synchronous voltage difference is the exchange of power and system,to achieve the dynamic compensation adjustment process.Details the basic control method of the SSSC set up the basic controller,with only the realization of the basic control cannot be good for transient operating conditions of power system,the problem such as Angle oscillation damping,design and attached a Wolf optimization algorithm based on(Grey Wolf Optimizer,GWO comes)power oscillation damping controller,using GWO comes to power deviation ΔP optimal minimum as the optimization objective function,the four steps of the algorithm by wolves iterative optimization,and the controller parameters of optimal solution is obtained,and the controller parameters of optimal solutions provide input controller.Based on this,the simulation model of power system connected to 100 MVASSSC with rated capacity was built,and the transient conditions such as power fluctuation of power grid and three-phase grounding short-circuit fault caused by unstable output power of wind power grid were simulated.It was verified that the SSSC introduced in this paper can play a good damping role and improve the stability of power system.