LVRT Capability Assessment of Grid Code Frequency Responsive VSWTG

Abstract

With increasing wind energy penetration and impending grid codes, it is important to enable wind based power plants to provide sensitive frequency active power response as well as connection capability during and after a short-term fault. Conventionally active power is given low priority during voltage disturbance and voltage ride through capability is assessed separately with frequency ride through capability. This paper assess the LVRT capability of frequency grid code compatible DFIG based VSWTG under frequency dependent power set-point neglecting current priority. Simulation tests conducted for a weak system shows improved LVRT capability of frequency responsive VSWTGs in comparison to normal VSWTGs. With active power output well above zero and turbine speed also remaining under limit during fault conditions, frequency grid code compatible VSWTGs can also satisfy FRT grid codes of many countries.