Principal Factors Affecting the Accuracy of Real-Time Power Monitoring Data in Large Public Buildings

Building energy monitoring system is an effective measure to provide the energy consumption information in large-scale public buildings. However, in actual operation process, many errors may occur in the existing measurement due to the low accuracy of the instruments and mistakes in human operation. This study proposed a novel method to improve the accuracy of power monitoring data at a low instrument cost. In this method, two sets of comparative data, obtained by conventional and high-precision instruments, respectively, were measured on a self-designed test rig. The changes of the relative differences between the two sets of data were quantitatively studied considering three factors, including load rate, cable cross-sectional area, and its length on the secondary side. The results show that the measurements should be carried out under recommended conditions in engineering applications when the load rate is at more than 20%, the cable cross-sectional area at 4 mm², and the length of cables less than 50 m. The method proposed in this study can effectively achieve the accuracy of energy consumption data through background processing based on the existing ammeters in large public buildings.