Fault Current Limiting System for 500kV Power Systems

Abstract

Recently, expansion in the scale of power systems and development of the localized power sources are leading to an increase in fault current of 500kV systems. In future, it is quite likely that the fault current at the interconnection of such power systems may exceed the rated short-time current of existing electric power facilities. As one of the solutions to this problem, a thyristor controlled series resonant type fault current limiter (FCL) is proposed to restrain the fault current. This paper deals with the FCL system configuration, the placement method of the FCL in power system, the outline of the FCL's specification and the operation method of the protective relay in the multi-machine system. Finally, the effectiveness of the FCL is evaluated from the viewpoints of limiting the fault current by simulation analysis. The FCL is shown to be a useful protection device for large, high capacity power systems.