Primary and secondary indices for power quality (PQ) survey reporting

Abstract

Routine monitoring involves many PQ monitors at fixed sites with readings able to be interrogated remotely and downloaded to a central database. The amount of data for one year is large, and innovative methods are needed to ensure that it can give useful insights. Primary indices are proposed to show whether a site is acceptable to specified standards and are mainly based on 95% values. Secondary indices are proposed to give additional insights. For variations, indices are proposed to give a measure of the impact on customer equipment beyond that incorporated in standards. Sag secondary indices are defined to give insights as to the factors responsible for poor sag performance. Indicative maximum acceptable values are given for secondary indices based on a recent Australian survey of several distributors.