In this paper, the basic design of DC line fault restart principle of Yongren-Funing HVDC project is firstly introduced. Then the protection configuration and response characteristics of DC fault recovery is theoretically analyzed. Subsequently, a simulation model of Yongren-Funing HVDC is built in RTDS real-time environment. Simulation of the DC line fault and corresponding fault recovery is performed. Responses of the typical electrical quantities such as voltage, current and power in the rectifier and inverter side are analyzed. In addition, field experiments results are compared with the ones gets from the simulation. This comparison study validates the effectiveness of the control and protection system. Moreover, the fault restart principle meets the design requirement. As a result, the fault restart principle and protection configuration provide in this paper is useful to the design and operation of other newly-built HVDC projects.

HVDC; DC line fault recovery sequence; RTDS; response characteristic