Impact Analysis and Performance Optimization of LVRT Control of Wind Turbine on Transient Overvoltage of Power System

Abstract

With the UHVDC transmission projects and the large-scale wind farms nearby put into operation, the problem of the power system transient overvoltage after AC/DC faults has become more and more prominent. It will seriously threaten the safety of the AC and DC devices, and has become a key factor restricting the UHVDC transmission capacity and the wind farm output power. The active power and reactive power dynamic characteristics of the wind power generation system in the low voltage ride-through process after the AC/DC fault are the important factors causing the transient voltage rise of the system. Therefore, combined with China's technical rule for connecting a wind farm to the power system, this paper firstly clarifies the control switching logic of wind power generation system in the grid fault through process. The transient active and reactive power output characteristics of the wind turbine during and after the fault are analyzed in detail. Then, the mechanism of transient overvoltage deterioration due to the wind farm LVRT (low voltage ride through, LVRT) process is discussed. On this basis, the impacts of LVRT-control on the wind turbine output power and the transient overvoltage are analyzed comparatively, and the sensitive factors affecting the system transient overvoltage are pointed out. Finally, suggestions for the LVRT performance optimization of the wind turbine are proposed, which can be used to guide the optimization of the LVRT control strategies of the wind turbines connected to grid in order to effectively suppress the system transient overvoltage level.