Detection method of voltage flicker

Abstract

The invention relates to a detection method of a voltage flicker. The detection method specifically comprises the steps of: acquiring a grid voltage, acquiring a high-sampling-rate grid voltage effective value sequence XH and a low-sampling-rate grid voltage effective value sequence XL; calculating original frequency spectra of the XH and the XL by utilizing windowing FFT separately, and correcting frequencies and amplitude values of the original frequency spectra by utilizing a frequency spectrum correction algorithm to obtain corrected frequency spectra SH' and SL'; and calculating a short-term flicker value and a long-term flicker value by utilizing the corrected frequency spectra SH' and SL' obtained in the step 2. By adopting double-sampling-rate Fourier analysis, the detection requirements for low-frequency flicker signals is satisfied by means of Fourier analysis of the low-sampling-rate sequence, and the analysis requirements for high-frequency flicker signals is satisfied by means of Fourier analysis of the high-sampling-rate sequence, thereby significantly reducing the voltage flicker calculation load and requirements for storage space. In addition, by adopting a method of carrying out interpolation fitting on dominant frequency and the short-term flicker value, the voltage flicker measurement precision is improved.

Description

technical field [0001] The invention relates to the technical field of power quality detection, in particular to a voltage flicker detection method. Background technique [0002] Voltage flicker is mainly caused by the fluctuating load of the steady-state power supply system, which is very harmful to the power load in the power grid, such as causing uneven rotation of the motor and motor, affecting the life of the motor and product quality. Accurate measurement of flicker value is a prerequisite for monitoring and managing voltage flicker in power systems. [0003] The International Electrotechnical Commission (IEC) defines voltage flicker as the human eye's visual degree of incandescent lamp flicker caused by voltage fluctuations, and recommends the square detection method. However, this method needs to use a band-pass filter to filter signals outside the flicker frequency range, and its parameters are difficult to design. [0004] Compared with the square detection metho...

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Problems solved by technology

[0006] In view of the above analysis, the present invention aims to provide a detection method for voltage flicker, which is used to solve the problems that the Fourier transform sequence in the traditional detection method is too long, resulting in a large amount of calculation, and it is difficult to realize real-time calculation of flicker.

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