A FREQUENCY-DOMAIN MODEL FOR 3 KV DC TRACTION DC-SIDE RESONANCE IDENTIFICATION

Frequency-dependent effects in railway traction power systems arise fr om the impedance of substation and locomotive line filters and the tra ction line. Harmonic noise from traction drives and substations can ex cite resonances and produce overcurrent or overvoltage conditions at c ritical points in the network. In this paper, the harmonic feeding imp edances of a 3 kV DC traction system seen from the rectifier substatio n, locomotive drive converter and pantograph terminals are presented. Several substation and locomotive filters are considered with a freque ncy-dependent traction line. Resonances attributed to the substation f ilter, locomotive filter and traction line are separate and distinct, the line introducing poles and zeros in the audio frequency (AF) range which vary in frequency and magnitude with locomotive position.