Experiences of using the 1 kV three phase supply in rural electricity distribution

Modern society is dependent on electricity distribution. The expectations for more reliable and continuous electricity are growing all the time. Short and long outages in electricity distribution have shown the vulnerability of modern society. The customers´ quality consciousness and the role of energy market authority have grown during the last years. In addition, to allow the rate of return of companies, the authority supervises power quality in the sense of reliability. In the near future, power quality is an actual part of the distribution regulation model. The focus of this paper deals with practical experiences of application of the three-voltage-level 20/1/0.4 kV system and results of studies in which alternative network solutions are evaluated. Network designs and practical experiences have shown that the 20/1/0.4 kV system is an economical solution compared to the traditional system when it enables replacing 20 kV medium voltage lines with 1 kV low voltage lines