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A System Harmonic Impedance Estimation Method Based on Three-point Screening Method

A technology of harmonic impedance and screening method, which is applied in the field of power quality control, can solve problems such as large estimation error and poor fitting degree, achieve high estimation accuracy, improve estimation accuracy, and reduce the effect of multiple correlations of independent variables

Active Publication Date: 2021-04-13
STATE GRID JIANGSU ELECTRIC POWER CO ELECTRIC POWER RES INST +3
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Problems solved by technology

However, the interference of background harmonics is a key factor affecting the accuracy of non-interventional harmonic estimation, but the traditional linear regression method is poor in fitting when the background harmonic voltage fluctuates, and in practice the background harmonic voltage often changes. And it is random, so the traditional linear regression method has a large estimation error

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  • A System Harmonic Impedance Estimation Method Based on Three-point Screening Method
  • A System Harmonic Impedance Estimation Method Based on Three-point Screening Method
  • A System Harmonic Impedance Estimation Method Based on Three-point Screening Method

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Embodiment Construction

[0041] The present invention will be further described below in conjunction with the accompanying drawings.

[0042] Such as image 3 As shown, a system harmonic impedance estimation method based on the three-point screening method includes the following steps:

[0043] Step 1: Collect voltage and current data at the PCC (Common Coupling Point);

[0044]Step 2: Perform Fourier analysis on the voltage and current at the PCC at different sampling times to obtain h-order harmonic voltage and current data at different times;

[0045] Step 3: Divide the h-order harmonic voltage and current data into one group according to three different sampling times, and use the three-point screening method to judge whether the root-finding discriminant b of formula 6 is satisfied 2 -4ac≥0, and at least one positive solution is guaranteed, if satisfied, it is a valid data set;

[0046] Step 4: Arrange the judged valid data groups into a new sequence from front to back according to the samplin...

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Abstract

The invention discloses a method for estimating system harmonic impedance based on a three-point screening method. First, a regression equation between harmonic data and system harmonic impedance is established according to the harmonic analysis equivalent circuit, and then the relationship between the measured and estimated quantities is used to The phase angle relationship of the three-point data is established and reduced to the form of a quadratic equation, and the voltage and current data at the common coupling point when the background harmonic voltage is stable are screened out through the root-finding discriminant formula, and finally the partial The least square method is used to solve the regression equation and estimate the harmonic impedance of the system side. The results of simulation examples show that the present invention can reduce the influence of background harmonic voltage fluctuations on system harmonic impedance estimation, and has higher estimation accuracy and better stability than traditional methods.

Description

technical field [0001] The invention relates to a system harmonic impedance estimation method based on a three-point screening method, belonging to the technical field of power quality control. Background technique [0002] At present, with a large number of power electronic equipment connected to the grid, the harmonic pollution caused by it has become one of the outstanding problems of the power quality of the grid. In order to ensure the power supply reliability of the power grid and ensure the quality of power supply, it is imperative to punish the electricity users who cause the grid harmonics to exceed the standard. Accurate measurement of users' harmonic emission levels and clear division of harmonic responsibilities are the prerequisites for reasonable rewards and punishments for power users. The estimation result of user harmonic emission level is obtained from the calculation of system equivalent harmonic impedance, so the key to evaluating user harmonic emission ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/18G06F30/20
CPCG06F17/18G06F30/20
Inventor 史明明张军付慧唐伟佳张国江李双伟张宸宇范忠
Owner STATE GRID JIANGSU ELECTRIC POWER CO ELECTRIC POWER RES INST
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