PROCEDURES AND GEAR TO DETERMINE DISTANCE TO SINGLE-PHASE SHORT-CIRCUIT IN THREE-PHASE ELECTRIC POWER LINE ( ALTERNATIVES ) Russian patent published in 2002 - IPC

FIELD: electrical engineering. SUBSTANCE: invention is intended for use on electrified railways for determination of distance to location of single-phase short-circuit to ground in three-phase electric power supply line of automatic lock-out features. Procedure 1 consists in determination of first short- circuited phase, in disconnection of line, in shorting of wires of first and second phases at known distance at finish of line, in grounding of wire of third phase at start and finish of line, in grounding of zero point or lead-out of second phase of power supply source, in connection of wires of first and second phases to power supply source, in measurement of voltage across terminals of power supply source between first and second phases, in measurement of current in wires of these two phases and in determination of location of single-phase short-circuit to ground by formula given in description of invention. Procedure 2 determines first phase of shorted line, disconnects line, shorts wires of first and second phases at start and finish of line, disconnects supply end of wire of third phase and connects it to ground at start and finish of line, grounds zero point or lead-out of third phase of power supply source, connects first phase to power supply source, measures currents in wires of first and second phases of line and determines distance to location of single-phase short-circuit to ground by formula presented in description of invention. Gear for realization of procedure includes voltage transformer, three current transformers, four single-phase switches, three straps and measurement module incorporating two matching transformers, two active-inductive resistors, two rectifiers and divider. Measurement module is connected to current transformers of first and second phases and leads-out of these phases on secondary side of voltage transformer. EFFECT: raised accuracy in determination of location of single-phase short-circuit to ground. 3 cl, 3 dwg