A New Method for Processing of Basic Electrical Values Based on Definition Formula in Time Domain

Abstract

Many applications involve digital processing of periodic signals. For example, both voltage and current in electrical utilities are periodic signals containing harmonic components [1, 2, 3, 4]. There are generally three steps associated with the digital processing of a signal. First, the signal is uniformly sampled and converted into a discrete sequence. Then, a block of data is constructed by looking at the sequence for a period of time neglecting everything that happens before and after this period. This period of time is referred to as the data window or observation interval. Finally, digital signal processing techniques such as the discrete Fourier transform (DFT) are applied to the samples within the data window to obtain the result. There are some requirements associated with the first two steps. The sampling frequency must be higher than the Nyquist frequency, which is twice the highest frequency of interest. A practical problem arises when the sampling frequency is high enough to satisfy the Nyquist theorem, but the sampling process is not synchronized with the signal to be processed.