DEVICE TO PROTECT DC TRACTION CIRCUIT IN CASE OF DAMAGED INSULATION OF SUPPORTS NON GROUNDED THROUGH RAILS

摘要

FIELD: electric traction vehicles; DC circuit fault protection. SUBSTANCE: in case of break-down of one of insulators 21 high voltage of contact system 22 passes through valve element 4 to additional wire 3 and further on through barring element 2 to current sensor 1. Additional valve element 8 will save voltage source 6 from damage. Other valve elements 4 will prevent voltage shunting in additional wire 3 by internal resistance of other supports 20. In this case voltage across current sensor 1 will be higher than voltage across second resistor 10, but lower than voltage across third resistor 11. This will cause appearance of signals at outputs of first and second comparators, 13 and 14, respectively, and no signal across output of third comparator 15 and integrating network 16. Such combination of signals at outputs of second comparator 14 and integrating network 16 makes 2 AND gate 17 operate. Inverting input of gate 17 is connected with output of integrating network 16. Output signal from 2 AND gate 17 passes to quick-acting circuit breaker 5 and indicating device 18. Contact wire 22 is disconnected from supply feeder of traction substation 23. EFFECT: enhanced reliability of protection. 2 cl, 1 dwg