Calculating combined amplitude and phase modulated power signal parameters

The ability to monitor and control the dynamics of the electric power grid is important. That is why the proposed revision to the IEEE Synchrophasor Standard IEEE C37.118 adds dynamic performance requirements. One of the new requirements is expected to be for accurate phasor and frequency measurements with a specified level of combined phase and amplitude modulation of the power signals. This paper describes the equations for this type of modulation. Direct solutions are developed for calculating the modulation parameters from measurements of the fundamental and first order sidebands of the modulated signal. These components can be determined by a Fourier transform of the signals. This analysis will help with the calibration of PMUs and the calibration of PMU calibrators generating such test signals.