Influences Of Wind Power Integration On Power System And Low Voltage Ride-Through Control Of Wind Power Generation System With DFIG

With the rapid development of wind power, The number of wind farms and wind turbine unit capacity of rapid growth. The impact of the centralized grid of large-scale wind farms for power system stability can not be ignored。The study on the stability analysis of power systems with wind farms gradually become a hot spot. Countries have issued a wind power operation specifications and requirements of the wind turbine must be of low voltage ride through capability to make the system able to maintain the stable operation。The method to improve the low voltage ride through capability of wind turbine has also been gradually attention.In this paper, it has been study the wind power system model, flow calculation and transient stability simulation analysis with large-scale wind power system with data of the Inner Mongolia Power Grid Dispatching and Communication Center. Analyzed the impact of large-scale wind power system angle stability and transient yoltage stability with the FASTEST power system simulation software. The results show that large-scale wind power access will reduce the stability of the system, some of the wind turbine voltage continues to decrease may be cause system voltage can not be normal recovery and collapse and system failure, When the voltage continued to drop, the wind turbine would be cut out the grid with th the role of the low voltage protection. Resection of large-capacity wind turbine cause the system to a significant loss of active source, so the system will still be instability. Access to the reactive power compensation device SVC, When System failure, the SVC to the system to provide sufficient reactive support to help fast recovery, thereby enhancing the transient stability of the system.After learning the domestic and foreign wind turbine control strategies and the low voltage through the Standard Research, made a detailed study of the dynamic mathematical model of the doubly-fed wind turbine, and based on the mathematical model to study the vector control strategies for wind turbine through the time-domain simulation analysis, indicating that vector control can improve the transient stability of the system, but through the standard, based on low-voltage vector control on the relative lack of wind turbine low voltage ride through capability.In order to improve the low voltage ride through capability of wind turbine, this paper presents an improved control strategy. Improved flux-weakening control strategy is to add compensation is on the basis of the original vector control, current control link, combined with the Lyapunov stability theorem and the transient time-domain simulation analysis to verify that the improvements in both theory and simulation control strategy compared with the original control strategy to improve the low voltage ride through capability of wind turbine, thus improving the transient stability of the system.