LMD interconnected electric power system low frequency oscillation analysis method based on wide area information

Abstract

The invention discloses an LMD interconnected electric power system low frequency oscillation analysis method based on wide area information. The method comprises the steps that various data signals in a preset area are integrated according to the order of the time point based on the low frequency oscillation state actually measured data under the interconnected electric power system fault so as to form an oscillation signal matrix, the time window length of the signals is acquired as the number of matrix rows, two periods of the lowest frequency mode in the known preset area are taken and the number of the matrix columns is the number of the measured oscillation signal types; LMD decomposition is performed on each column of signals in the signal matrix so as to obtain oscillation modal components and residual trend components; and the correlation parameters of each oscillation modal component are calculated according to the oscillation modal components, wherein the correlation parameters include instantaneous frequency, instantaneous amplitude and damping. The method has the following advantages that local envelope optimization can be realized, the endpoint effect of LMD decomposition can be effectively improved and oscillation characteristic identification based on the decomposition result can be realized.

Description

technical field [0001] The invention relates to the technical field of power system low-frequency oscillation analysis, in particular to a method for analyzing low-frequency oscillation of an LMD interconnected power system based on wide-area information. Background technique [0002] The interconnection of large-scale power systems is becoming more and more common. The purpose is to improve the reliability and economy of power generation and transmission. However, the expansion of the system scale makes the grid structure and operation mode complex and diverse, leading to more prominent system stability problems. The weak interconnection of the large regional power grid limits the transmission capacity of the tie line, and will greatly reduce the damping between the systems. Some weak interconnections even lead to negative damping in the system, causing the system to appear low-frequency oscillations with a frequency of 0.1-2.5 Hz, and participate in this oscillation. The r...

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Problems solved by technology

However, due to the limitations of the decomposition method itself, problems such as over-envelope, under-envelope, and modal aliasing will appear in the process, and the corresponding physical meaning of each component obtained is not clear. At the same time, the instantaneous frequency is calculated using the Hilbert method Potential edge effects and negative frequency issues that may occur with instantaneous amplitudes and instantaneous amplitudes limit the practical applicability of the method

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