METHOD OF CHANGING 3,3 kV DC ELECTRIFIED TRACT SECTION OVER TO SINGLE-PHASE 25,5 kV AC AND DEVICE TO THIS END Russian patent published in 2009 - IPC B60M3/02 

FIELD: transport.

SUBSTANCE: invention relates to the methods of changing 3.3kV-DC electrified track sections over to single-phase 27.5 kV AC for all existing electrified track sections. The proposed method consists in that, first, the three-phase alternating current is converted by rectifier-converter hardware into a single-phase AC. For this, no special high-power rectifier-converter substations are erected but the existing DC substation infrastructure is exploited including from primary DC supply voltage lead-ins to 3.3kV-DC buses.

EFFECT: reduced costs of changing over to AC thanks to using existing D C traction substations followed by erection of new ones, ruling out constructing neutral inserts in overhead system, complete symmetry in phase loading of outside electric power supply lines over their entire length, reduced power losses in said lines and at electric power stations.

3 cl, 1 dwg