Optimization of AC power measurements for immunity to spectral leakage due to imperfect phase-locking

Abstract

Power measurements can benefit from spectral analysis. It may, however, also lead to errors that are not immediately recognizable, caused by spectral leakage due to imperfect phase-locking in measurement systems. This paper analyses this problem for low-frequency AC power measurements. The conclusion is that if any spectral decomposition is made, care should be taken not to use excessive measurement times, and that the phase-locked loop bandwidth should be kept as low as possible.