Measurement method for subsynchronous and supersynchronous phasors of power system voltage harmonic wave

A power system and phasor measurement technology, applied to the phase angle between voltage and current, measuring devices, measuring electrical variables, etc., can solve problems such as excessive selection of adjustment parameters, reduced frequency resolution, and reduced detection accuracy. Achieve the effect of eliminating fence effect, improving measurement accuracy and eliminating leakage

Inactive Publication Date: 2019-06-14
CHINA SOUTHERN POWER GRID COMPANY
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Problems solved by technology

However, if the adjustment parameter is too large, the frequency resolution will be reduced and the detection accuracy will be reduced.

Method used

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  • Measurement method for subsynchronous and supersynchronous phasors of power system voltage harmonic wave
  • Measurement method for subsynchronous and supersynchronous phasors of power system voltage harmonic wave
  • Measurement method for subsynchronous and supersynchronous phasors of power system voltage harmonic wave

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Embodiment Construction

[0032] The technical scheme of the present invention is further described in detail below.

[0033] The embodiment of the secondary synchronized phasor measurement method of the present invention comprises the following steps:

[0034] (1) Obtain voltage signal data: According to the IEC 61000-4-7 standard, collect the voltage sampling data y(n) of 50 continuous power frequency cycles at the PMU installation point; where n=0,1,...,N -1, where n is an integer, indicating the current sampling point; N is a positive integer, indicating the total length of the sampled data;

[0035] (2) Time domain windowing processing:

[0036] The voltage sampling data y(n) obtained in step (1) is processed by time-domain windowing using Kaiser window function, and the time-domain expression of Kaiser window function w(n) is:

[0037]

[0038] Among them, I 0 (β) is a Bessel function, n=0, 1, 2, . . . , N / 2. β is an adjustable parameter, which can adjust the main lobe width and side lobe ...

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Abstract

A measurement method for subsynchronous and supersynchronous phasors of a power system voltage harmonic wave comprises the following steps of (1) collecting power grid voltage signals and performing data preprocessing, and performing time domain Kaiser window processing on the obtained voltage sampling data; (2) sequentially performing local discrete Fourier transform in frequency bands on the windowed data, and calculating spectral line amplitude values in each frequency band; (3) counting and arranging the spectral line amplitude values in each frequency band except a fundamental frequency to obtain a spectral line having a specific amplitude value; (4) performing double-spectral-line interpolation calculation between the two adjacent maximum amplitude values for the obtained spectral line amplitude values to obtain a frequency correction coefficient, thereby determining frequencies of sub-synchronous and super-synchronous components; and (5) calculating by using the frequency correction coefficient to solve a corrected formula of the amplitude values and phases, and obtaining the amplitude values and phases of the subsynchronous and supersynchronous components. According to themeasurement method for the subsynchronous and supersynchronous phasors of the power system voltage harmonic wave, Kaiser window function processing is performed on the sampled data in equal intervalfrequency bands, and the obtained specific spectral lines are subjected to correction processing to obtain the subsynchronous and supersynchronous frequencies, amplitude values and phases.

Description

technical field [0001] The invention relates to a power system voltage harmonic sub-synchronous / super-synchronous phasor measurement method. Background technique [0002] In recent years, with the continuous construction and development of large-scale wind power transmission and direct current transmission projects, problems such as subsynchronous and supersynchronous oscillations in power systems that may be induced have gradually become prominent. In the power grid, it mainly manifests as divergent or constant-amplitude subsynchronous and / or supersynchronous current, voltage and power harmonics, and the oscillation frequency will change with the change of the grid operation mode. This will affect the safe operation of the power grid and equipment and even cause serious stability accidents or equipment damage. Therefore, there is an urgent need for dynamic measurement of sub(super) synchronous harmonics. [0003] The existing phasor measurement unit (Phasor Measurement Un...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R25/00
Inventor 李金张喜铭胡荣
Owner CHINA SOUTHERN POWER GRID COMPANY
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