Influence of the design and operation of protection and control on power quality

The power quality experienced by electricity supply customers is dependent upon the design and operation of the power network and the reliability of the plant and equipment. Power quality is extensively affected by power system faults and how efficiently these are dealt with by the protection and control equipment. Voltage dips are one of the most prevalent events on the utility power system which can adversely affect the power quality. In South Africa, the loss suffered by major industrial customers due to voltage dips is more than #120 million per annum. This article explores the influences of the design and operation of power system protection and control on supply quality, focusing on voltage dips, and possible ways to improve power quality through the adoption of different protection technologies, philosophies and application practices.