Estimation of the Frequency Measurement Error Caused by the Aperture Delay and Aperture Jitter of ADC

To measure frequency of electrical power networks, digital measurement methods are widely used. These methods are highly accurate in real electrical networks, characterized by the presence of flicker, noise and harmonics. One of the most promising evaluation methods is associated with determining the signal phase rate of change over time. One of the causes of the measurement error is the ADC aperture jitter and ADC aperture delay. The paper considers these effects and their influence on the considered technique measurement error of frequency. Analytical expressions are obtained that allow estimating the frequency measurement error. An error analysis was performed in terms of measuring system parameters (sampling frequency, number of samples, total measurement time) and the parameters of the input signal (initial phase, frequency, amplitude). Aperture jitter is analytically modeled as a stochastic function characterizes a normal and uniform distribution and by sinusoidal function. It is defined that in the case of representation by a uniform distribution law, the estimate of the error is approximately 20% greater than in event of representation by a normal distribution. To estimate the error using Matlab, a simulation model was developed.