Contextualisation and reporting of Quality of Supply data

Abstract

Quality of Supply (QoS) concerns the interaction of the loads on the electrical grid with the voltage supplied by generation, in the transmission and distribution portions of the grid. Most power quality standards and regulatory frameworks, describe power quality only in terms of voltage behaviour. This energy regulator requires, for licensing purposes, that data on voltage behaviour should be recorded and submitted for auditing purposes. A large portion of Southern African utilities therefore use power quality instruments to record only these voltage parameters. This is cost-effective and fulfils the requirements set by regulator, but valuable other information, already present in the measurement data, is often not utilised. In this dissertation, a large power quality database is investigated, through exploratory visualisation techniques. This was done by identifying several contexts for power quality data. The information obtained through these investigations was used to create visualisations and interactive dashboards. This may aid, utilities and consumers alike, in the management of power quality in their respective businesses. The developed model was implemented and validated using real-life data produced by more than 600 QoS recorders located all over Southern Africa. To demonstrate how the model works, and to evaluate the results, the implementation for two QoS parameters: voltage magnitude and voltage sags, will be presented. These two were selected, since practical experience with a number of South African utilities indicated that these parameters are prioritised in managing distribution networks.