Sistema de transmissão CC para o acionamento de motores CA — Parte II: Análise dos transitórios de faltas e da proteção do sistema

The operation of PWM motor drives with long cables results in several undesired phenomena. In order to avoid them all, it was proposed in a previous work that the long cable be used to connect the rectifier to the inverter, which would then be placed beside the motor, thus establishing a DC line transmission. In the mentioned work, the additional benefit of the proposal, which is the reduction of the required copper amount, was quantified. Regarding this alternative drive system configuration, the present paper brings an analysis concerning protection aspects, characterizing the transient phenomena related to different fault types within the DC line and evaluating the current peaks and transient overvoltage levels that may take place. In this way, the thermal and dielectric solicitation in the cable and semiconductor devices, in the occurrence of faults, can be estimated.