Voltage booster scheme for enhancing the fault ride‐through of wind turbines

This study presents a new scheme for a continuously variable (CV) series braking resistor (SBR) with independent per phase controller. The CV‐SBR is a CV and not stepwise. A novelty of the work presented is that the CV‐SBR operates on the whole range of wind speeds. The proposed scheme is applicable to fault ride‐through (FRT) of fixed speed wind turbines (FSWTs). The CV‐SBR scheme is compared to the single‐step (SS) and multi‐steps (MS) SBRs. The CV‐SBR scheme is modelled and simulated in PSCAD/EMTDC™. The performance of the wind turbine is studied for balanced and unbalanced fault scenarios. The CV‐SBR scheme is advantageous over the other two candidates with its ability to limit the fault current and reduce the turbine speed deviation at any wind speed. The CV‐SBR is employed with a static synchronous compensator (STATCOM) to allow FRT of FSWT connected to weak grid during nearby faults and to deliver the reactive current required by some grid codes. The CV‐SBR scheme is successful in reducing voltage disturbance's consequences on the generator's mechanical system. Simulation results show that the CV‐SBR allows FRT of FSWT connected to weak grid where the STATCOM alone is not able to sufficiently enhance the FRT of FSWT during nearby faults.