Indices for assessing harmonic distortion from power quality measurements:Definitions and benchmark data

For many years, electricity distribution companies have used sustained inte rruption indices as indicators of the reliability of service provided on th eir systems. Today, however, many electricity consumers are adversely affec ted by more subtle voltage disturbances such as harmonic distortion. In res ponse to the increased sensitivity of end-use equipment, many utilities are implementing extensive monitoring systems to assess service quality levels . Such monitoring systems yield massive databases of service quality data. This paper presents indices developed to quantify system service quality wi th respect to measured harmonic distortion levels. Example benchmark values for the indices are calculated using data from a national distribution pow er quality data collection project.