Real-time frequency tracking and harmonic measuring method for AC sampling of power system

Abstract

The invention discloses a real-time frequency tracking and harmonic measuring method for the AC sampling of a power system, which is characterized by comprising the steps: an AC sampling input is made to enter an analog-to-digital converter at a fixed sampling rate; the analog-to-digital converter at the fixed sampling rate respectively outputs a first segment of digital signals with the length of N points and a second segment of digital signals with the length of N points to enter a first fast Fourier module; the first fast Fourier module outputs phase angles of the highest frequency components of the first segment of digital signals with the length of N points and the second segment of digital signals with the length of N points, and sends the phase angles into a phase discriminator one after another; the phase discriminator outputs a correction frequency, and sends the correction frequency into a digital signal reconstruction filter; the digital signal reconstruction filter performs digital reconstruction sampling on the first segment of digital output signals with the length of N points, of the analog-to-digital converter at the fixed sampling rate, according to the correction frequency, and sends an obtained N-point reconstruction sampling signal into a second fast Fourier module; the phase angle output of the highest frequency component of the second fast Fourier module is sent into the phase discriminator; the third segment of digital signals with the length of N points, of the analog-to-digital converter, enter the first fast Fourier module; and the phase discriminator judges the phase angle based on accuracy requirements, and outputs a correction frequency to a digital signal reconstruction filter. After the iterations of the process reach M, the output of the second fast Fourier module is the values of respective subharmonic components of the AC sampling signal, and the output frequency of the phase discriminator is the frequency of the AC sampling signal.

Description

Technical field [0001] The invention belongs to the technical field of AC sampling measurement application, and more specifically relates to power system power frequency AC sampling measurement real-time frequency tracking and harmonic measurement technology. Background technique [0002] With the rapid development of the power system, the capacity of the power grid continues to increase, and the structure is becoming increasingly complex. The automation of real-time monitoring and dispatching in the power system is very important, and digital acquisition is an important link in achieving automation, especially how to accurately and quickly Collecting various simulated electricity in the system has always been a hot spot for electricians. According to the different sampling signals, it can be divided into two categories: DC sampling and AC sampling. DC sampling is to convert AC voltage and current signals into 0-5V DC voltage. The main advantage of this method is that the algori...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the shortcomings of traditional AC sampling technology such as high requirements on A / D conversion speed and difficulty in improving the accuracy of data acquisition of power frequency signal AC power, and provide a fast real-time frequency tracking and high-precision AC power Measurement methods

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