Improving the power quality on medium voltage power lines

Abstract

The purpose of an electrical power system is to deliver energy to consumers. This should be done with the utmost reliability and economy. When power outages occur the normal routine of society is disrupted. A power system comprises of many diverse items of equipment and to improve the reliability and economy of a power system, this equipment must be of high standard, with good performance and consistency. The industries of today rely upon good power quality because poor power quality can cause a halt in production and in some cases a decrease in product quality. Power quality plays an import rote in the efficiency and success of a business. The purpose of this research is to investigate the possible causes of poor power quality that could be avoided by improving the configuration and condition of the network. The factors that are of concern for this study is the power flow distribution, steady state voltage and the dynamic voltage control of the network. This is done by investigating the current network layout for possible improvements. These layouts are compared with a power system simulation package to determine a suitable solution against poor voltage levels on the network. Recorded measurements of voltage dips and interruptions are characterized to determine a probable cause of these incidents. This in turn points out areas which affect the power quality of the network. The focus area for this research is a banana farm located in Mpumalanga that produces 15% of the total banana crop in South Africa, They have to supply to their customers every day and any delay they have, reduces the quatity of their product. Bananas have a three-week window period from the time of picking to being consumed by their customers. Temperature control of the cooler is an important factor that plays a major role in ripening cycles and the quality of the product. Each time the temperature of the cooler in which the bananas are kept during packaging and distribution, drops during a voltage dip or a power outage, the life-time of the product decreases by a few days.