Risk Evaluation of Results when Utilizing Software Simulations to Identify a Harmonic Offender in a Power System

Willem Stemmet, Gary Atkinson-Hope

Cape Peninsula University of Technology, South Africa

Summary: When evaluating harmonic software packages, some of the default element models (e.g., six-pulse drive) and analysis methodologies used are different and cause risk to results. Another problem is when multiple drives are present, the injections from drives add vectorialy at the PCC. Thus, a further risk to results arises as the vector addition is highly dependant on the methodology (e.g., referencing of drives) used to obtain the actual value for the phase angles for the injections. Also drives are often harmonic offenders, causing transgression of IEEE 519 limits. The focus of this paper is to develop a method to identify a harmonic offender and do risk evaluation of results. Indices are developed for identifying a harmonic offender (HOFFENDER) and to determine errors to results DHOFFENDER,  respectively. Risk flowcharts are also developed as a tool to assist and simplify the comparison of default element models and methodologies used by the three packages evaluated in this paper. The indices and flowcharts comprise a new method to determine if a drive is a harmonic offender or not and to do risk to results evaluation. Three case studies within two scenarios are conducted to demonstrate the effectiveness of this method.