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A Sub/Supersynchronous Harmonic Detection Method for Power System

A power system and harmonic detection technology, applied in the direction of measuring devices, measuring electrical variables, instruments, etc., can solve the problems of reducing frequency resolution, decomposing, restricting applications, etc., and achieve the effect of expanding the range of signal decomposition

Active Publication Date: 2019-08-09
TSINGHUA UNIV +3
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Problems solved by technology

However, there are problems such as endpoint effect and modal aliasing in the application of the EMD method, especially when the frequency of the two components in the signal is within 2 times the frequency, EMD cannot decompose the two components, resulting in modal aliasing. Reduced frequency resolution
Since the frequency between the sub / supersynchronous harmonic and the fundamental or sub / supersynchronous harmonic is close to or within 2 times the frequency, this shortcoming restricts the application of HHT in sub / supersynchronous harmonic detection

Method used

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  • A Sub/Supersynchronous Harmonic Detection Method for Power System

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Embodiment Construction

[0017] Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0018] These and other aspects of embodiments of the invention will become apparent with reference to the following description and drawings. In these descriptions and drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to represent some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited by this limit. On the contrary, the embodiments of the present...

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Abstract

The invention discloses a power system sub / super-synchronous harmonic detection method comprising the following steps: extracting and separating power-frequency components; carrying out grouping according to modal aliasing conditions; extracting a grouping signal with the highest-frequency harmonic component, and judging whether modal aliasing occurs; if modal aliasing occurs, carrying out frequency shift modulation and empirical mode decomposition to get an intrinsic mode function corresponding to sub / super-synchronous harmonics contained in the group; carrying out amplitude phase and frequency compensation; carrying out Hilbert transform to get the instantaneous frequency and amplitude of the sub / super-synchronous harmonics contained in the group; separating the sub / super-synchronous harmonics contained in the group; and repeating the steps until the sub / super-synchronous harmonics contained in all the groups are separated. The advantages are as follows: based on a frequency shift method of signal modulation, the signal decomposition range of empirical mode decomposition is extended by increasing the frequency ratio of two sub / super-synchronous harmonic components; and the method is applicable to real-time accurate detection of sub / super-synchronous harmonics in a power system.

Description

technical field [0001] The invention relates to the technical field of power system dynamic monitoring and power quality, in particular to a sub / super synchronous harmonic detection method of a power system. Background technique [0002] In recent years, wind power, photovoltaic and other new renewable energy power generation has expanded rapidly, and its penetration rate has continued to increase. The problem of subsynchronous oscillation caused by the interaction between the wind turbine controller and the AC grid has become increasingly prominent, affecting the safe operation of the grid and equipment. , and even cause serious stability accidents or equipment damage, which is extremely harmful. [0003] Subsynchronous oscillations in the power grid are mainly manifested as continuous growth (divergence) or constant amplitude subsynchronous and / or supersynchronous current, voltage and power harmonics with large amplitudes. Accurately detect the amplitude of sub / supersynchr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R23/165
CPCG01R23/165
Inventor 谢小荣贺静波宋瑞华张锋郭小龙陈军占颖
Owner TSINGHUA UNIV
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