Fault Ride Through Improvement Employing Individual Phase Linked Dynamic Braking Resistor for Wind Energy Integrated MMC-HVDC Transmission Network

Modular multilevel converter (MMC) based high voltage DC transmission (HVDC) is competitive for grid integration of remotely placed renewable energy sources. Usually, a dynamic braking resistor (DBR) is placed in parallel with the transmission line to protect the HVDC link from overvoltage during severe AC side low voltage faults. However, during moderate low voltage fault at the point of common coupling of AC grids, it introduces multiple switching and ripples in the HVDC link voltage. This work presents an individual phase-linked dynamic braking resistor-based control method to control the HVDC link voltage at the point of common coupling during AC side low voltage faults. In this study, a permanent magnet synchronous generator (PMSG) for integrating wind energy is considered. Real-time digital simulation (RTDS) has been used to build the entire system. The proposed technique redudces multiple switching and ripples in the HVDC link voltage during symmetrical and asymmetrical low voltage disturbances.