Fault current limiting system for 500-kV power systems

Recently, expansion in the scale of power systems and development of localized power sources are leading to an increase in fault current of 500-kV systems. In the 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 of 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 systems, the outline of the FCL's specification, and the operation method of the protective relay in the multimachine 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. (C) 1999 Scripta Technica.