High-accuracy synchronous phasor measuring method

Abstract

The high-accuracy synchronous phasor measurement method belongs to the field of automatic measurement technology of power system. On the basis of spaced sampling circulation DFT, when the system frequency is deviated from rated frequency, the influence of frequency deviation can be calculated to make the frequency and phasor measurement have higher accuracy. The field tests show that when the sampling frequency is 4800 Hz and phasor correction calculation frequency is 200 Hz, its static accuracy indexes are: phasor magnitude error is less than 0.5%, phasor phase angle error is less than 1 deg.C and frequency calculation error is less than 0.01 Hz, and its dynamic accuracy indexes are: phosar magnitude error is less than 1%, phasor phase angle error is less than 1 deg. and frequency calculation error is less than 0.01 Hz.

Description

technical field [0001] A high-precision synchronized phasor measurement method belongs to the technical field of electric power system automatic measurement. Background technique [0002] When the traditional synchronized phasor algorithm deviates from the rated frequency, the obtained phasor amplitude, phase angle and frequency have large fluctuations (errors). In order to improve the accuracy of the Phasor Measurement Unit (PMU, Phasor Measurement Unit), this patent proposes a new synchronized phasor algorithm based on fixed-interval sampling cycle DFT to overcome the shortcomings of the traditional algorithm and obtain high-precision frequency and synchrophasors. In recent years, with the in-depth development of theoretical research and application promotion of phasor measurement units, the improvement of phasor measurement accuracy has become more important and urgent. [0003] The existing measurement method is based on cyclic discrete Fourier transform (DFT). In prin...

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Problems solved by technology

[0003] The existing measurement method is based on cyclic discrete Fourier transform (DFT). In principle, when the system frequency deviates from the rated frequency, the calculation error increases with the increase of the offset, so the applicable measurement range is small. Accuracy is not ideal

When the frequency of the power grid is offset by 50Hz, the calculation accuracy cannot meet the requirements of "Technical Specifications for Real-time Dynamic Monitoring (Control) System of Electric Power System"

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