Performance Investigation of a Monitoring Scheme for Low Voltage Grids with a Single Grounded Neutral

Low voltage distribution grids (LVDGs) are evolving from their traditional passive behavior into highly active systems. Their secure and reliable operation will require effective control schemes which in return require reliable and accurate monitoring systems. Most of the related existing works rely on the three-phase Weighted Least Squares (WLS) state estimation method which is used mainly on Medium Voltage Distribution Grids (MVDGs). However due to different characteristics between MVDGs and LVDGs this method may not be suitable for monitoring LVDGs. This paper investigates the performance of the WLS state estimator on a radial low voltage test feeder and due to the random nature of the measurement errors, the analysis is conducted in a Monte Carlo fashion. The investigation indicates that a significant error is imposed in the monitoring of the LVDG which is related to the loading conditions and the asymmetric operation of the distribution grid.