METHOD AND DEVICE FOR CONTROLLING FEEDER SWITCH OF AC, 27.5 AND 2 × 27.5 kV TRACTION SUBSTATIONS Russian patent published in 2008 - IPC H02H3/06 H02H11/00 

FIELD: electrical engineering; controlling feeder switches of alternating-current traction substations.

SUBSTANCE: proposed method for controlling switching apparatuses such as feeder switches of 27.5 and 2 x 27.5 kV AC traction substations includes primary determination of cause of expected disconnection of switch by means of digital terminals as early as before switch disconnection, that is, it is found out if switch disconnection will occur as result of malfunction of terminal protective gear due to processes in traction load current or short circuit; to this end percentage of third harmonic in current through switch or shift angle between first harmonics of current through switch and voltage across 27.5-kV traction substation buses are evaluated during period between sending OFF- and ON-operation commands to switch; terminal sends commands for connection or disconnection of switch in compliance with processes occurring in traction load current and residual voltage; in addition, point of short circuit in disconnected section of traction line is located by means of proposed device.

EFFECT: enhanced safety in operation.

2 cl, 1 dwg