Design of a matrix fault current limiter using low-power PTC resistors

This paper presents a new matrix fault current limiter (FCL) using low-power PTC resistors. In this study, some of the general aspects of a PTC matrix consisting of a parallel-series (matrix) combination of PTC resistors are considered. The critical issue under normal operation of a PTC matrix is the heat transfer among the elements of the matrix, so the cooling method has a great impact on the number of parallel branch of the PTC matrix. Statistical variation of PTC cold resistance is another issue for PTC matrix operation. In this paper, the matrix operation is investigated by simulation result of an LC circuit with V_C = 1kV and finally the number of low-power PTC resistors is calculated for a sample single phase 12 kV network with rated current of 1250 A_rms.