Simulation of a DC Superconducting Fault Current Limiter for the Design of Online Monitoring System

Abstract

Superconducting fault current limiter (SFCL) combined with high voltage circuit breaker is a promising method to solve the fault current problem in the power system. However, there hasn’t been any online monitoring system for this kind of extreme low temperature (around -200°) environment with high voltage (160kV). This paper proposes a new method which can measure the temperature of SFCL and pressure of liquid nitrogen in the dewar flask. And it can be helpful for timely detection of internal faults and result in the more effective current limitation. Based on Nan’ao VSC-MTDC demonstration project, the rated voltage and current of the SFCL are respectively 160kV and 1kA. Multi-terminal high-voltage direct current were established by PSCAD/EMTDC based on a SFCL model with COMSOL. From the designed models, temperature and pressure in the dewar vessel under normal and fault condition were respectively analyzed. Thus the partially abnormal signals can reflect the fault mode. Present simulation results shows that the method of SFCL fault diagnosis was feasible to gauge the temperature signals and pressure signals. Online monitoring for temperature and pressure can judge SFCL fault mode. We are now constructing a prototype of 160kV SFCL. There will be experimental results of total monitoring system after the construction.