Metering type optical current and voltage combined transformer harmonic analysis device and method

A combined transformer and harmonic analysis technology, applied in spectrum analysis/Fourier analysis, instruments, calculations, etc., can solve problems such as fence effect, "spectrum leakage, inaccurate measurement of power grid harmonic data, etc., and achieve easy interface, improve the accuracy of harmonic analysis, and facilitate the realization of hardware programming

Inactive Publication Date: 2019-08-06
HARBIN INST OF TECH +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to propose a measurement optical Device and method for harmonic analysis of combined current and voltage transformer

Method used

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  • Metering type optical current and voltage combined transformer harmonic analysis device and method
  • Metering type optical current and voltage combined transformer harmonic analysis device and method
  • Metering type optical current and voltage combined transformer harmonic analysis device and method

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specific Embodiment approach 1

[0039] Specific implementation mode 1: The following specific description of this implementation mode, a method for harmonic analysis of a metering optical current voltage combined transformer, includes the following steps:

[0040] Step 1: Convolute the Hanning window and the Nuttall window to obtain the NHC window function;

[0041] Step 2: Perform L time-domain convolution calculations on the NHC window function, that is, L-order self-convolution, to obtain the NHSC window function;

[0042] Step 3: Discrete Fourier transform the discrete time domain signal of the NHSC window to obtain a discrete frequency domain signal, and then perform bispectral interpolation and least squares polynomial approximation fitting.

[0043] This implementation mode proposes a new type of Nuttall hybrid self-convolution window function, that is, the NHSC window function. The window is a hybrid convolution of the Nuttall window and the Hanning window and then L-order self-convolution, which uses ...

Embodiment

[0044] Example: figure 2 The amplitude-frequency response curves of different L-order NHSC window functions are given. It can be seen that with the increase of L, the main lobe width of NHSC slowly widens, but the side lobe characteristics can be rapidly improved. Therefore, for power harmonic signals , choosing an appropriate L-order NHSC window function to window the signal can effectively improve the FFT analysis accuracy of harmonics. Combined with the principle of window function selection, if the main lobe width and side lobe characteristics cannot be satisfied at the same time, the requirements of side lobe characteristics are often sacrificed at the expense of the main lobe width, so L=4 is selected as the order of the NHSC window function.

[0045] In the present invention, the NHSC window is a hybrid self-convolution window function of the Hanning window and the Nuttall window, and the NHC is the hybrid convolution window function of the Hanning window and the Nutta...

specific Embodiment approach 2

[0046] Specific embodiment two: this embodiment is a further description of specific embodiment one, and the difference between this embodiment and specific embodiment one is that the functional expression of the Nuttall window in the step one is:

[0047]

[0048] Among them, R N (n) is the function expression of the rectangular window, N is the number of discrete sampling points, and n is the period.

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Abstract

The invention discloses a metering type optical current and voltage combined transformer harmonic analysis device and method, and relates to the technical field of power quality harmonic analysis. Thedevice comprises a passive optical current transformer, a passive optical voltage transformer, a merging unit and a secondary side harmonic analyzer; the input end of the merging unit is a digital interface of the passive optical current transformer and the passive optical voltage transformer, the output end of the merging unit is a digital interface of the secondary side harmonic analyzer, and the merging unit is used for merging and outputting digital quantity of three-phase voltage and three-phase current signals. According to the device and method, the characteristics that the side lobe peak attenuation speed of the Nuttall window is high and the main lobe of the Hanning window is narrow are utilized, and the advantages are further improved after self-convolution. Double spectral lineinterpolation and numerical fitting correction are carried out, so that the harmonic analysis precision is greatly improved, and hardware programming realization is facilitated. The method is suitable for the technical field of harmonic analysis.

Description

technical field [0001] The invention relates to the technical field of harmonic analysis of power quality, in particular to a harmonic analysis device and method for a measurement-type optical current-voltage combined transformer. Background technique [0002] With the advancement of the power electronic process of the power system, the harmonic detection and control problems in the power grid have attracted widespread attention due to the grid-connected use of a large number of power electronic devices. Therefore, harmonic analysis is particularly important in power systems. However, whether the harmonic value can be accurately analyzed is closely related to the measurement of the transformer and the analysis accuracy of the harmonic algorithm. [0003] The electromagnetic current transformer has simple structure and safe and reliable operation. The accuracy of measuring the steady-state current can reach the accuracy of a few ten-thousandths or even higher. However, in ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/15G01R23/16
CPCG06F17/156G01R23/16
Inventor 张国庆赖增强李洪波于文斌王贵忠侯英伟
Owner HARBIN INST OF TECH
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