Power quality measurements in the 10–30 kV grid in Copenhagen

This paper presents the results of a power quality pilot project which was conducted in cooperation with the Danish network operator DONG Energy. Power quality parameters such as the voltage level, harmonics, interharmonics, voltage dips and swells etc. have been measured in different locations in the 10 and 30 kV grids during a period over approximately 6 months from the beginning of March through August 2007. The measurements show that the power quality parameters in general are well below current limits in e.g. EN 50160. However, the short circuit level in the centre of Copenhagen is higher than the general level in Denmark and the situation are likely to be different where the short circuit level is lower and/or disturbing loads may account for a larger part of the total load. It is expected that the project will be expanded during 2009, such that LV and grids in other parts of the country can be included, in order to get a better overview of the general power quality level.