According to the requirement in IR46 of considering the influence of the quadriform waveform when it tmeasures the harmonic energy, this paper introduces two methods to measure the power after analyzing the quadriform waveform’s impact on the power quality, namely the integral method and Fourier transform. Moreover, it deduced the corresponding power measurement theory before it conducts the experiments and the error and measurement uncertainty analysis of these two methods under the influence of sinusoidal signal and quadriform waveform. This study can provide theoretical and experimental support for the application of the IR46.