Effects of power quality limits on LV-network design

摘要

For the design of the LV-network, not only the requirements with respect to the loading of the cable play an important role, but also power quality aspects such as flicker and voltage variations should be taken into account. In this paper, various requirements with respect to adequate earthing, voltage variations, flicker and overloading are investigated and compared. As the current approach with respect to the assessment of these quantities is limited, more risk based asset management approaches have been evaluated in this study. By evaluating these requirements for both rural, sub-urban and urban conditions, the differences in the driving factors for the LV-network design become apparent for geographical customer distributions. This study showed among others that the optimisation of the fuse breaking capacity based on the number of connected customers can for instance greatly increase the possible length of a LV-feeder. Moreover, for a network structure consisting of a single line the impedance based requirements, i.e. flicker and safety, are driving. If a branched network structure is used, the requirements with respect to voltage variations and overloading become more important.