Parametric design method and application study of a 160-kV resistive-type DCSFCL in a three-terminal flexible DC transmission system

The intermittent access of renewable energy sources leads to a significant increase in fault short-circuit currents in power grid. DC superconducting fault current limiters (SFCL) can limit short-circuit currents in flexible DC transmission systems, which work in combination with direct current circuit breaker (DCCBs) to protect the grid system effectively. However, for the parameter design of DC superconducting fault current limiter (DCSFCL), it is difficult to balance the economics of the device and its adaptability to different fault situations. In this paper, a cross-mapping design methodology for the DCSFCL is proposed and applied in the Nan'ao flexible DC transmission project, China. A cross-mapping method is designed combining the critical parameters of DCSFCL and the system parameters. A three-terminal simulation model of the flexible DC transmission system is constructed through MATLAB/Simulink and the design process of DCSFCL parameters is introduced. A cyclic calculation approach is proposed for the design of DCSFCL parameters through three fault conditions of the power system. Meanwhile, impact current short-circuits test and artificial ground short-circuit test were conducted on the prototype. Test results show that the designed DCSFCL meets the requirements of practical applications.