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On-line monitoring method of low-frequency oscillation of power system

A low-frequency oscillation and power system technology, applied in the direction of reducing/preventing power oscillation, circuit devices, measuring devices, etc., can solve the problems of noise sensitivity, unsatisfactory non-stationary oscillation mode fitting ability, etc., and achieve good dynamic characteristics and short observation time Effect of window length, high pattern resolution

Inactive Publication Date: 2012-01-04
WUHAN UNIV
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AI Technical Summary

Problems solved by technology

Prony is widely used in engineering, but this method is sensitive to noise, and its ability to fit non-stationary oscillation modes is not ideal
ESPRIT and matrix beam can effectively improve the robustness of the algorithm to noise by performing singular value decomposition on the constructed Hankel matrix, dividing the signal-to-noise space and eliminating noise interference factors, but the algorithm’s mode resolution ability, observation time window length and non-stationary Signal monitoring capabilities require further study

Method used

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  • On-line monitoring method of low-frequency oscillation of power system
  • On-line monitoring method of low-frequency oscillation of power system
  • On-line monitoring method of low-frequency oscillation of power system

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Embodiment

[0041] First introduce the parameter setting principles that the present invention needs to involve:

[0042] The frequency range of the low frequency oscillation is 0.1Hz-2.5Hz, and the frequency domain bandwidth of each TFA unit is 2Δω. In order to make the filtering calculation cover all the low-frequency intervals, N parallel settings such as figure 1 The TFA unit shown, where N should be an integer not less than 2π(2.5-0.1) / (2Δω), at this time the center frequency corresponding to each unit is ω k =0.2π+2Δω(k-1), k=1, 2, L, N, the mode resolution that each unit can achieve is 2Δω. When Δω takes a small value to improve the mode resolution, the number of units N will increase, which reduces the operation efficiency; when the number of units is reduced to improve the operation efficiency, the value of Δω becomes larger, and the mode resolution will decrease accordingly. For this reason, the present invention first performs parallel filtering calculation on the oscillation...

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Abstract

The invention relates to an on-line monitoring method of low-frequency oscillation of a power system. In the on-line monitoring method, parallel filtration calculation is carried out at an oscillation frequency by creatively utilizing time-frequency atom compound band-pass filter function to obtain oscillation mode number, practical oscillation frequency distribution and real-time amplitude information. On the basis of the redundancy of adjacent real-time amplitude information, various oscillation mode amplitudes and decay time constants can be obtained by utilizing least square optimization estimation; based on the obtained oscillation frequency distribution, amplitude and decay time constant, a low-frequency oscillation signal model can be built, wherein only an initial phase and direct-current component amplitude of each mode are unknown; and optimization estimation is carried out on the model by utilizing a particle swarm optimization algorithm to obtain the initial phase and the direct-current component amplitude. The method has good noise robustness, can be used for accurately distinguishing compound oscillation models, is favorable for the strong non-linear mode analysis ofthe power system and is convenient for on-line monitoring and application.

Description

technical field [0001] The invention relates to an on-line monitoring method, in particular to an on-line monitoring method for low-frequency oscillation of a power system. Background technique [0002] Monitoring and analyzing the dynamic behavior of power system under disturbance, determining its dynamic characteristics and studying appropriate countermeasures (including various control measures) is one of the most important and complex tasks in power system design and operation. The main monitoring and control objects of the dynamic characteristics of the power system are the parameters of the electromechanical mode oscillation, namely frequency, damping and amplitude. The weak AC connection in the early stage of regional power grid interconnection and the operation mode that tends to the limit of stability under the power market form are more likely to induce low-frequency oscillations among the regional power grids, so the monitoring and analysis of dynamic characterist...

Claims

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Application Information

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IPC IPC(8): G01R23/00G01R25/00H02J3/00H02J3/24
Inventor 林涛刘林徐遐龄
Owner WUHAN UNIV
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