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Harmonic oscillation suppression method and device for power grid

A harmonic oscillation and power grid technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, active power filtering, etc., can solve problems such as background harmonics and harmonic oscillations

Inactive Publication Date: 2014-07-23
YANSHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method and device for suppressing harmonic oscillation of the power grid, so as to overcome the defect of background harmonics in the prior art that harmonic oscillation occurs in the propagation of the power grid

Method used

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  • Harmonic oscillation suppression method and device for power grid
  • Harmonic oscillation suppression method and device for power grid
  • Harmonic oscillation suppression method and device for power grid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] The power grid harmonic oscillation suppression method in this embodiment is as follows: figure 1 shown, including the following steps:

[0056] In said step A, specifically include:

[0057] Step s101, detecting the grid voltage u at the output end of the active power filter installed at the end of the transmission line a , u b , u c and current i a i b i c , separated to obtain the harmonic voltage content u ah , u bh , u ch and harmonic current content i ah i bh i ch . In this embodiment, specifically include:

[0058] (1) According to the formula

[0059] u d u q = 2 3 sin ωt - ...

Embodiment 2

[0074] The power grid harmonic oscillation suppression method in this embodiment is as follows: figure 2 shown, including the following steps:

[0075] Step s201, detecting the grid current i at the output end of the active power filter installed at the end of the transmission line a i b i c , multiply the current by m to get the command current i of the active power filter in the three-phase coordinates af i bf i cf , where m is a real number greater than 1.

[0076] Step s202, making a difference between the command current and the actual output current of the active power filter, performing PI control on the difference and then performing PWM modulation to obtain the driving signal of the three-phase bridge arm of the active power filter, and controlling the Converter.

Embodiment 3

[0078] A power grid harmonic oscillation suppression device in this embodiment is as follows: image 3 As shown, it includes an active power filter, an electrical parameter detection unit, a command current acquisition unit, a PI control unit, a drive signal acquisition unit and a converter control unit; wherein, the active power filter is installed at the end of the transmission line; the The electrical parameter detection unit is connected to the active power filter for detecting the electrical parameters of the output grid of the active power filter; the command current acquisition unit is connected to the electrical parameter detection unit for Acquire the command currents of the three phases a, b, and c of the active power filter according to the electrical parameters; the PI control unit is connected with the command current acquisition unit and the active power filter respectively, for combining the command current with the active power filter The difference between the...

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Abstract

The invention belongs to the technical field of harmonic suppression of a power grid and discloses a harmonic oscillation suppression method for the power grid. The method comprises the following steps of: detecting electrical parameters of the power grid at an output end of an active power filter (APF) arranged at the tail end of a transmission line, and acquiring instruction current of phases a, b and c of the APF according to the electrical parameters; and subtracting the instruction current and the actual output current of the APF, performing PI control on the difference, performing pulse width modulation (PWM), so as to obtain the three-phase bridge arm driving signal of the APF, and controlling a converter according to the driving signal. The invention also discloses a harmonic oscillation suppression device for the power grid. The harmonic oscillation of the power grid is suppressed from a bran-new view, and a scheme of suppressing the harmonic oscillation of the power grid is completed. The length of the transmission line of the power grid is equivalently elongated, so that reflected waves are reduced even eliminated, the harmonic oscillation is avoided, and particularly the harmonic oscillation can be well suppressed when the characteristic impedance of the transmission line of the power grid is slightly changed.

Description

technical field [0001] The invention belongs to the technical field of grid harmonic suppression, and in particular relates to a grid harmonic oscillation suppression method and device, especially when the characteristic impedance of the grid transmission line changes slightly, the harmonic oscillation can also be well suppressed. Background technique [0002] The increasing number of non-linear loads has introduced a large number of background harmonics to the power grid. When the power grid is lightly loaded, the background harmonics propagating in the power grid are likely to cause harmonic oscillation, which seriously endangers the capacitor and inductance equipment in the power grid. [0003] At present, most of the suppression strategies for this harmonic oscillation are based on R-APF (Resistance-Active Power Filter, resistive active power filter). Dissertation on Harmonic Suppression of Power Grids. The invention suppresses the background harmonic oscillation of th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/01
CPCY02E40/22Y02E40/40Y02E40/20
Inventor 孙孝峰李志超李昕
Owner YANSHAN UNIV
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