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System harmonic impedance calculation method based on mixed overall least square method

A technique of least squares, harmonic impedance, applied in impedance measurement, measurement of resistance/reactance/impedance, measurement devices, etc.

Inactive Publication Date: 2016-05-04
国网电力科学研究院武汉能效测评有限公司 +3
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Problems solved by technology

The overall least squares method considers the errors of the dependent variable and the independent variable at the same time, but because this method ignores the reality that the coefficient matrix only contains part of the error, and treats the errors of the coefficient matrix and the observation value matrix as independent and equal precision, there are also shortcomings. place

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  • System harmonic impedance calculation method based on mixed overall least square method
  • System harmonic impedance calculation method based on mixed overall least square method
  • System harmonic impedance calculation method based on mixed overall least square method

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Embodiment Construction

[0032] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

[0033] figure 1 It is a system and user equivalent circuit schematic diagram of a system harmonic impedance calculation method based on the hybrid overall least squares method provided by the present invention. figure 1 middle, is the system harmonic voltage, Z sh is the system harmonic impedance, is the hth harmonic voltage of the common connection point, is the hth harmonic current of the common connection point.

[0034] figure 2 It is a flow chart of calculating the harmonic impedance of a power system based on a system harmonic impedance calculating method based on a hybrid overall least squares method provided by the present invention. figure 2 in, u pcc(t) is the instantaneous value of the bus voltage at the common connection point collected, i pcc (t) is the instantaneous value of current collected, is the hth h...

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Abstract

The present invention belongs to the field of harmonic impedance calculation method design and more particularly relates to a power system harmonic impedance calculation method. The method is characterized in that firstly, the voltage and current measured at a PCC are subjected to Fourier decomposition, the effective values of voltage and current obtained after the decomposition and an initial phase are constructed into a harmonic voltage vector sequence and a harmonic current vector sequence under a target frequency of a common connection point; then a regression equation is established by the voltage and current harmonic vector sequences; and finally a system harmonic impedance regression coefficient is solved by the mixed overall least square method, and the value of harmonic impedance is obtained. The invention provides the system harmonic impedance calculation method based on a mixed overall least square method, independent variable and dependent variable errors are completely considered, the partial error of an overall minimum least-square coefficient matrix is considered closely, a regression coefficient estimation error can be effectively eliminated or reduced, and the system harmonic impedance solution accuracy is improved.

Description

technical field [0001] The invention belongs to the field of harmonic impedance calculation method design, in particular to a power system harmonic impedance calculation method. Background technique [0002] With the progress of the times, the role of power electronic devices in the process of power conversion and grid connection is becoming more and more important, and the scope of application is becoming wider and wider. However, at the same time, the use of these nonlinear devices has brought more Serious harmonic distortion and other power quality problems; in addition, the rapid development of high-speed rail technology has led to increasingly serious harmonic problems in power systems. The accurate measurement of system harmonic impedance is the basis for research on harmonic power flow calculation, harmonic responsibility division, harmonic emission level, and harmonic source identification. [0003] At present, the measurement and estimation methods of harmonic impe...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/16G01R27/08
CPCG01R27/16G01R27/08
Inventor 肖楚鹏陈聪邱泽晶章家义许朝阳丁胜陈小飞
Owner 国网电力科学研究院武汉能效测评有限公司
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