The Research On Active Disturbance Rejection Control Strategy For SVC In Wind Farm

In recent years, wind power grows fast, and voltage stability and reactive powercompensation of wind power system are main problems in wind farm. Now most of windturbines are asynchronous motors, when they grow active power they also draw much reactivepower , which lead voltage of wind power system unstable. A common way to solve thisproblem is compensate reactive power by SVC, Static var compensator play a role not onlydepends on its capacity and installation point, but also on its controller. Active DisturbanceRejection Control is a control method which does not rely on accurate model of system, so ithas good robustness and adaptability. In this paper, a static var compensator controller wasdesigned based on ADRC strategy. Main tasks are as follows:(1) In wind power system an active disturbance rejection controller for static varcompensator was designed and researched. Because the output of wind farms is a wide rangeof unpredictable changes with the time variable, in this paper, the static model of the windfarm was seen as a PQ bus, and dynamic stability of the voltage target was obtained throughthe establishment of a multi-machine infinite bus system with TCR + TSC type SVC, thenADRC controller was designed. The simulation results show ADRC controller can quicklyand timely compensate reactive power, and when the system had failure，it also can quicklyreturn compared with the PI. The rapidity and robustness of ADRC are better.(2) A static bifurcation study was done about SVC and Parameters of Linear activedisturbance rejection controller through bifurcation theory. In this paper，the voltage stabilityimpacts of SVC with ADRC was analyzed through bifurcation theory, the bus voltagesaddle-node bifurcation boundary of wind power system was calculated by using LADRCparameter Kp as bifurcation control parameters. From simulation results, we can see SVC canimprove active power and reactive power of wind power system, and enhance the system’svoltage stability, increase of Kp can improve the voltage stability of the wind farm .