Transients of Short-Circuits and Fault Clearance in 6-Pulse Diode Rectifiers

Abstract

The paper addresses the short-circuit transients in 6-pulse diode rectifier bridges. It includes also an investigation into the transients resulting from the subsequent fault clearance. Unit-step functions are efficiently used for representing the diode characteristics and emulating the fault switching actions. The short-circuit fault and its subsequent clearance are simulated by means of a time-dependent shunt resistance at the rectifier terminals. The governing set of simultaneous algebraic and differential equations are solved using the Mathematica software. The presented case studies illustrate the impact of the rectifier’s pre-fault loading condition, the circuit parameters, the fault duration, and the rated frequency of the three-phase supply. A special case study is conducted in order to validate the model and the computer program