Method and system for frequency detection of power signals

Abstract

The present invention relates to a method and system for detecting the frequency of electric power signals. The method comprises: performing direction output on a sampled forward signal sequence to generate a defold sequence; truncating the forward signal sequence and the defold sequence to generate two groups The truncated signal sequence; the cosine function and sine function of the reference frequency are multiplied by the forward signal sequence, defold sequence and two groups of truncated signal sequences to generate four sets of real frequency vector sequences and imaginary frequency vector sequences; The imaginary frequency vector sequence and the real frequency vector sequence are digitally filtered, and then integrated to generate four sets of imaginary vector integral values ​​and real vector integral values; the four sets of real vector integral values ​​and imaginary vector integral values ​​are converted into four phases, and the four phases are transformed into For the initial phase and the cut-off phase, the difference between the cut-off phase and the initial phase is converted into a full phase difference, and the preset sampling frequency, preset sequence length and full phase difference are converted into a power signal frequency. By implementing the present invention, a signal frequency with higher accuracy can be obtained.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a method and system for detecting the frequency of electric power signals. Background technique [0002] The frequency measurement, phase measurement, amplitude measurement, etc. of the power system are all measurements of sinusoidal signal parameters in essence. The power signal is a sinusoidal signal in nature, and Fourier transform is the basic method to realize the parameter measurement of the sinusoidal signal, which is widely used in the power system. However, with the development of parameter measurement technology, the problems of Fourier transform become more and more prominent, and it is difficult to further meet the requirements of high-accuracy calculation of sinusoidal parameters in power systems. [0003] In the measurement of sinusoidal signal parameters in power systems, there are various parameter measurement methods, such as zero-crossing method, filter...

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Problems solved by technology

[0005] Based on this, it is necessary to provide a frequency detection method and system for power signals in view of the above-mentioned sinusoidal signal parameter measurement method for low-frequency power signal parameter measurement accuracy and poor anti-noise interference

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