Characteristics and Recovery Performance of VSC-HVDC DC Transmission Line Fault

As a new approach of DC transmission scheme, Voltage Sourced Converter based HVDC (VSC-HVDC) transmits electric energy by connecting rectifier and inverter through DC transmission line, which is the same as LCC-HVDC. However, the fault performance and relevant restart demand are different due to that VSC-HVDC is based on voltage sourced converter. This paper analyzes the mechanism of DC line-to-ground fault and line-to-line fault in VSC-HVDC scheme, and then proposes the recovery demand of temporary faults at overhead line scheme. By establishing an electromagnetic transient model under PSCAD/EMTDC, the performance under DC transmission line transients has been thoroughly investigated. According to the characteristics under simulation, the solutions of key points during recovery process are proposed, which include the grounding design, adopting monopolar topology and modifying the transformer type etc.