Measurement of Symmetrical Component Powers with a Revenue Metering Chip

Three phase power measurements can be decomposed into ‘distortion’ and ‘unbalance’ dimensions with a combination of Fourier transforms and symmetrical components analysis. This exposes many degrees of freedom concealed by traditional power measurements. The approach is computationally intensive, until recently beyond the capabilities of common metering chips. This paper describes the implementation of combined FFT and symmetrical component power definitions in a modern metering chip, followed by tests to confirm the accuracy of the measurements and reveal the hidden symmetrical component power flows. As with harmonic powers, negative and zero sequence powers can flow in the opposite direction to the positive sequence power. Disaggregation of the symmetrical component power flows allows a more accurate allocation of losses between the supplier and consumer.