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Electric system low-frequency oscillation detection method

A low-frequency oscillation and power system technology, applied in measurement devices, spectrum analysis, measurement of electrical variables, etc., can solve problems such as limiting the application range of the algorithm, lack of theoretical basis, etc., to reduce the degree of modal aliasing and reduce the impact of end effects , the effect of reducing damping loss

Inactive Publication Date: 2013-02-20
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Problems solved by technology

A new nonlinear and non-stationary data processing HHT (Hilbert-Huang transform, HHT) method has been introduced into the field of power system low-frequency oscillation signal analysis, but this method lacks a theoretical basis, and the end-point effect existing in the algorithm analysis process and the damping caused by sieving The loss and the modal mixing problem of the algorithm itself limit the application range of the algorithm

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  • Electric system low-frequency oscillation detection method
  • Electric system low-frequency oscillation detection method
  • Electric system low-frequency oscillation detection method

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example

[0137] The method of the present invention is used to detect a low-frequency oscillation sampling signal x(t), and its signal characteristics are as follows: Figure 5 As shown, the signal is a power sampling signal with low-frequency oscillation, which contains two low-frequency oscillation modal components, and also contains measurement noise. The sampling spectrum is 100Hz, and the sampling time is 0-20s, with a total of 2000 sampling points.

[0138] After the signal has been processed by steps 2 and 3, the result of the denoising symmetry algorithm is as follows: Image 6 shown. The signal does not contain noise and high-frequency components, and the signal is symmetrical about the horizontal axis. Continue to the following steps for processing.

[0139] Step 4 is the key content of the present invention. After the empirical mode decomposition of a series of method transformations, the decomposition results of the low-frequency oscillation signal are as follows Figure ...

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Abstract

The invention discloses an electric system low-frequency oscillation detection method. On the basis of the existing nonlinear and non-stable signal empirical mode decomposition algorithm, the improved empirical mode screening algorithm enables the electric system low-frequency oscillation detection method to adapt to low-frequency oscillation signal processing, decomposed eigen mode components are combined with low-frequency oscillation mode physical expression meaning, and accordingly all low-frequency oscillation mode parameters of low-frequency oscillation sampling signals are recognized. The electric system low-frequency oscillation detection method reduces influence of the endpoint effect through improved mixed endpoint forecast, removes overshoot and undershoot by adopting triple B spline interpolation, simultaneously effectively reduces mode aliasing degree, analyzes and detects aliasing mode parameters through refined complex wavelets, controls algorithm screening depth through the improved energy elementary error screening stopping condition, reduces damping loss of mode components, and accordingly effectively improves low-frequency oscillation mode characteristic parameter detection accuracy.

Description

technical field [0001] The invention belongs to the technical field of power system informatization, and more specifically, relates to a method for detecting low-frequency oscillation of a power system. Background technique [0002] Low-frequency oscillation is a type of accident that occurs frequently in modern power systems and has a serious impact on the stable operation of the power system. It has become one of the important factors that threaten the safe and stable operation of the interconnected power grid and restrict the transmission capacity of the power grid. [0003] At present, there are two main methods for studying low-frequency oscillations in power systems: the first one is based on the structural model of the power system, establishes differential equations through model parameters, and analyzes the stability of the system according to the first theorem of Lyapunov stability , mainly represented by the characteristic root QR method. However, this method is ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16G01R23/165
Inventor 易建波黄琦井实张昌华卢有亮孟劲松蔡东升
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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