Improving the Accuracy of Power Grid Frequency Measurements Using a Method Based on the Analysis of Phase Increment

Currently, it is important to be capable to quickly and precisely measure the frequency of voltage of the power grid. This is necessary for the management and control of the electrical network, as well as for the correct operation of a number of electrical devices. You can see a lot of methods for measuring the frequency of digital signals, one of them is an approach based on the analysis of phase increment. The purpose of this work is to consider possible ways to increase the accuracy of this method and evaluate their effectiveness. The following possible ways to improve the accuracy of measuring the frequency of the electrical network when using a technique based on the analysis of phase increment are described in the paper: the use of digital filtration; a method based on the calculation of the derivative of the straight line (LDCM) connecting the samples spaced for the period of the input signal; the use of the method of least squares (LSM). The effectiveness of the methods is evaluated by simulation mathematical modeling. In this paper, it is assumed that the mains voltage was converted to digital format by using an ideal ADC, the quantization error of which is not taken into account in this problem. It is also supposed that the sampling frequency is many times higher than the maximum value of the frequency range of the signal. Modeling is carried out by using the Matlab package. In paper it is established that from the point of view of accuracy, the most effective modification is the use of the FIR filter, from the perspective of consideration of the measurement time - LDCM. The application of LSM allows to implement to measure the frequency with higher accuracy than the Shifting Window Average Method. At the same time, the use of LSM requires much more computing power than all the methods listed above, which makes its use ineffective in this case.