Comparative analysis of Grid forming and Grid following controls for Type-3 and Type-4 Wind Turbines

Abstract

With an accelerated inclusion of renewable energy generators in the power system, the inertia support traditionally provided by conventionally powered synchronous generators is lagging, and power system stability is reducing. This grid-supporting behavior will now have to be provided by the power converters of renewable energy sources with the help of power electronics. Grid forming control refers to the idea of the converter’s ability to set its frequency and voltage by means of emulating similar characteristics as that of conventional synchronous generators. Most of the protection and control studies on grid forming control for wind turbines have been done using a simple power system model containing the generator and an infinite AC bus and very less insight is available for grid forming generators in a realistic power system. This study aimed to apply the grid forming control strategy on DFIG (Type-3) and full converter wind turbines (Type-4). For this, the MIGRATE benchmark models in RSCAD/RTDS were used for the comparison of the key power indicators for both grid forming and grid following controlled modes. This was followed by the development and validation of the grid forming controller as a black-box model using IntervalZero and RTDS software in the loop setup (SIL).