Study On SVS Control Strategy For Low Voltage Ride Through In Wind Farm

With the rapid development of the wind power in recent years, it takes more and more in the proportion of the entire power system, whose impact is gradually paid more attention by people. Especially in the power system failure, how to maintain wind turbine on-line and support the grid voltage recovery, become a research hotspot.TSC,SVC and STATCOM are important devices of reactive power compensation and voltage regulation. STATCOM has a superior performance and dynamic response speed in low-voltage, but small rated capacity. Combined with a larger capacity of TSC and SVC but sharp decline in compensation ability at low voltage situation, it proposes to let TSC, SVC and STATCOM work together so as to constitute a shunt var compensation system (SVS).In this paper, it proposes the basic circuit topology of SVS and sets up the mathematical model based on TSC, SVC and STATCOM, which also analyzes its working principle and operating characteristics. It proposes a control strategy which combines constant bus voltage with prevention of voltage collapse. It also designs a control algorithm based on classical PI control which coordinates the distribution of reactive compensation. Further more, which uses the fuzzy control theory to improve the system response speed and control accuracy. The paper establishes a system-level simulation model to prove the proposed SVS hybrid device has a good effect of reactive power compensation, enhancing the low voltage ride through capacity of the wind farm effectively.