Analysis of installation errors of a low-voltage current transformer operated energy meter using in-service data

Abstract

This study analyzed the installation errors associated with a low-voltage metering system with a focus on the reversal of secondary polarities of the current transformers (CT) and the mismatch of CT ratio and meter current ratio. This was achieved by introducing these errors into an existing 300/5A CT-operated metering system and computation of the energy estimated from the loads using the measurement carried out on-site. The largest energy loss (66.6%) occurred when the meter current ratio was greater than the CT ratio and the least energy loss (7.2%) occurred when the polarities of two CTs were reversed. This approach provides a cost-effective and quick estimate of energy loss in the event of any of these connection errors in the metering systems.