Method for measuring frequency of power system

Abstract

The invention provides a method for measuring the frequency of a power system, which is mainly applied to a power system. The method comprises the steps of sampling input signals at intervals to obtain discrete equally-spaced sampling points; carrying out direct current filtration on the equally-spaced sampling points; accumulating the discrete points slightly exceeding a fundamental wave period point number by taking a point near a peak value as a starting point for the filtered data, if the accumulated sum is zero, recording the last point, and if the accumulated sum is not zero, sequentially reducing from the last point until the accumulated sum reverses, and recording the point enabling the accumulated sum to reverse; and determining the period of a measured signal through the recorded point, the sampling interval number between the point and the starting point and the reversed accumulated sum to obtain a frequency value. According to the method, the theoretical basis is that an upper integral of a trigonometric function on a fundamental wave period is zero, higher harmonics are not needed to be filtered, the anti-interference is strong, the realization is simple, and the accuracy, the reliability and the rapidness of fundamental wave frequency measurement are improved.

Description

technical field [0001] The invention relates to a measurement technique applied to a power system, in particular to a method for frequency measurement of a power system. Background technique [0002] Frequency is an important parameter that reflects the operating state of the power system. [0003] Commonly used frequency measurement methods mainly include hardware frequency measurement and software frequency measurement. The principle of hardware frequency measurement is to pass the signal to be tested through a filter to filter out harmonic components, then convert the conditioned sinusoidal signal into a square wave signal of the same frequency through a voltage comparator, and finally capture the rise of the shaped square wave through a digital processor Edge and falling edge moments, and then through counter counting and simple mathematical operations, so as to obtain the frequency of the signal to be measured. The hardware frequency measurement method is very suscept...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and provide a method for measuring the frequency of a power system, which can effectively solve the problems of poor precision and slow response in the application process of ordinary frequency measurement methods, and improve the Measure noise immunity

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