Joint Simulation Study on Load Characteristics of Wind Turbines in Low Voltage Ride Through Process

Abstract

ObjectiveThe grid fault of voltage drop will cause severe variations to the load of wind turbines, and seriously affect the safe and stable operation of wind turbines. With the increasing of the wind turbine scale, the blade length and the tower height increase continually, leading to the increase of the sensitivity of load characteristics to the system parameter fluctuations. Therefore, it is necessary to study the load and vibration characteristics of key components in the process of grid voltage drop.MethodsA data interaction method based on dynamic link library and Socket communication was proposed, and a joint simulation method of Simulink and Bladed was established. Firstly, based on a 3.4 MW wind turbine model, the joint simulation platform was verified by a given wind speed variation condition. Then, the relationship between the overall performance of the unit and the load of the blade and tower during low voltage ride through (LVRT) was studied.ResultsThe amplitude of grid voltage drop has a great impact on the generator power, and has little impact on the wind turbine control parameters. In the process of LVRT, the blade pitch angle and rotational speed of the wind turbine fluctuate for a long time, the load change at the outer blade span is greater than that at the inner blade span, the blade tip displacement increases, and the vibration frequency of the tower is close to the natural frequency. These potential risks should be considered in wind turbine design.ConclusionThe joint simulation platform can effectively simulate the aerodynamic performance of the wind turbines and the transient characteristics of the component loads, and provide a reference for the optimal control of the unit.

Keywords

• new energy power generation
• wind turbines
• joint simulation
• low voltage ride through (lvrt)
• transient characteristic
• load