Power Quality Study and Analysis of Different Arc Welding Machines

Abstract

Electrical welding machines are among the most pollutant loads due to their strong nonlinear behavior. As a result, utilities have established new criteria for connecting welding machines in the grid. One approach that can provide good results in this context is based on modeling this special load and performing simulation studies. In this paper, two different computational models were developed in PSCAD/EMTDC to help the connection evaluation process and power quality studies. Furthermore, instead of a conventional power quality analysis, a power theory for non-sinusoidal voltages and currents is needed to analyze three-phase welding machines. The conservative power theory (CPT) allows an advanced analysis of the load’s characteristics as it decouples the power factor into different load conformity factors that are associated with specific characteristics in the load. The analysis and discussions are based on simulations and experimental measurements obtained at the terminals of two different welding machines. The results help to demonstrate the main advantage of the CPT compared to conventional approaches, which is related to its general application for single-phase and three-phase disturbing loads under non-ideal supply voltage conditions.