Compensation of harmonic disturbances in the Tunisian SAHEL railway supply system

The Tunisian SAHEL railway supply system of 68 km length track is fed by one electrical substation (ESS) 150kV/25kV. The overhead line is modeled as distributed circuit which presents parallel and series resonances. In the drive system, the DC motors are fed by half bridges which generate current harmonics in the line. The major supply system problems caused by harmonic current in the line are presented, as overvoltage and psophometric current in telecommunication cable. Moreover, the leakage current into the earth and the long distance from substation which produces electromagnetic interference are analyzed. To reduce the disturbances in railway supply system, several solutions are studied. Indeed, the problems presented previously may be reduced by changing of drive converter or by changing of the topology of the line or by using filters.