A new method of wind turbines modeling based on combined simulation

Wind power has reached a significant penetration level in the power system worldwide. Grid codes are proposed to safe guard power system with large scale wind power integration. To verify grid code compliance, wind turbine integration characteristics should be verified based on test and simulation results. Therefore, accurate simulation model need to be developed. Since wind turbine model are generally developed to fulfill specific purpose, there are three categories as follow: electromechanical transient model for the study of wind power integration in power system; electromagnetic transient model for the purpose of analyzing wind turbine electrical transient characteristics; and model used to vindicate wind turbine design and control strategy concerning load calculation, mechanical dynamic analyzing etc. However, neither of these models aims at analyzing the interaction between mechanical components and electrical components. This paper introduces a new method of modeling and combined simulating of aerodynamic, mechanical, control and electrical systems in two simulation software platforms. The wide used software tools GH Bladed and MATLAB/Simulink were utilized. According to the method, mechanical, aerodynamic and control (pitch control and torque control) model is specified in GH Bladed, while electrical model (concerning grid, generator and converter) was implemented in MATLAB. In the process of simulation, the two separate models were synchronized via a communication interface which was based on TCP/IP protocol. A 2.5MW wind turbine was modeled and simulated using the presented combined simulation method. Wind turbine simulation results during grid fault were verified with low voltage ride through test data to certify the accuracy of the combined simulation model. Based on the simulation results, mechanical dynamic on blades and drive train during grid fault was presented and the simulation method's further application in analyzing the interact between wind turbine and grid system was proposed.