CONDUCTION THROUGH SENSING AND INVERTER PROTECTION SYSTEM

摘要

Case 2568 A control or protection system for a line commutated inverter detects mode 2 conduction-through faults and initiates a control sequence for recovery without shutting down the inverter. A conduction sensor in each leg provides a signal representing conduction and this is compared with a signal representing the forbidden interval when conduction should not occur in that leg. When conduction is detected in a forbidden interval it normally indicates a mode 2 conductionthrough fault and the gating pulses are advanced for at least the next two pulses to occur immediately but with a limit of 60.degree.. This causes commutation of the legs which are carrying the conduction-through fault current provided that sufficient volt-seconds remain in the AC part of the circuitry.