Analysis of commutator configurations for the protection of a line-commutated converter

Methods of protecting a line-commutated converter and load in the event of line-induced converter faults are investigated. The process of protection is found to be composed of a two part process: (1) detecting a fault and (2) implementing corrective action during the postfault period. To this end, five commutator configurations are presented. Simplified postfault circuit models for each commutator are derived, experimentally verified, and subsequently utilized for purposes of analysis. The results of the analysis are used to identify critical operating parameters. The five commutator configurations are compared on the basis of such criteria as application suitability, component sizing, postfault peak line/load currents, and postfault time durations