Integration of renewable energy sources with LCC HVDC system using a new circuit topology with DC fault ride-through capability

The integration of remote renewable energy sources located near the long-distance HVDC transmission corridor to the HVDC system is an active area of research. This study presents a new fault-tolerant scheme using a modular soft-switched DC-DC converter with high-voltage gain to integrate renewable energy sources to LCC-based HVDC systems. The configuration, operating principle and mathematical modelling of the new DC-DC converter are described in this study. As both the charging and discharging processes takes place through resonant circuits, zero current switching of all the switches used in the converter is achieved. The proposed scheme has the inherent fault-tolerant capability and enables fast recovery from commutation failures in the main LCC HVDC system. The operation of the proposed scheme during various fault scenarios is analysed and explained in this study. The performance of the proposed scheme and its fault ride though the capability is verified using a simulation model built in PSCAD/EMTDC and an experimental prototype.