Evaluating flicker damping capabilities of wind turbine inverters with grid following and grid forming controls applying the proposed IEC 61400-21-4

The variation of output power, due to wind speed variation, turbulence and wind gust, as well as periodic disturbances such as tower shadow and wind shear cause flicker emission in the grid during continuous operation of grid connected wind turbines. Researches were mainly focused on the flicker contribution of stall-controlled wind turbines (WT) only. This paper aims to analyze both flicker contribution as well as damping capabilities of modern wind turbines using a simulation model of a MW-level wind turbine (WT) with full converter. The effect of the wind turbine control as well as grid side converter control on flicker is studied using flicker measurement method of recently completed IEC 61400-21-4 [1] standard and its test cases are applied for comparing the flicker damping capability of the modelled grid-following (GFL) and grid-forming(GFM) converter controller at the point of common coupling (PCC).