Working condition On-line identification and early warning method of low frequency oscillation leading model of electric power system

Abstract

The invention discloses a working condition on-line identification and early warning method of a low frequency oscillation leading model of an electric power system. A non-stationary signal is decomposed and handled by an ensemble empirical mode. By the adoption of a filter, a cross correlation coefficient and a signal energy weight coefficient, leading model components are screened out, a cross correlation function of the leading model components is obtained by a natural excitation technique, the cross correlation function is used as the leading model to identify signals, variable amplitudes and frequencies are identified by the adoption of a teager energy operator, phase positions are identified by the adoption of a time domain peak peak-value method, damping ratio is identified by the adoption of an energy analysis method and is applied to the working condition on-line early warning of low frequency oscillation leading model. The working condition on-line identification and early warning method has the advantages that the dynamic real-time leading model information of a system can be identified quickly and precisely and man-made excitation is not needed, and anti-noise performance is strong, and has an important meaning for maintaining a safe and stable on-line identification and early warning of the electric power system.

Description

Technical field [0001] The invention belongs to the technical field of power system low frequency oscillation online monitoring, and more specifically relates to an online identification and early warning method for power system low frequency oscillation dominant mode working conditions. Background technique [0002] With the continuous deepening of the national grid interconnection, the low-frequency oscillation of the power system has increasingly become one of the prominent problems that threaten the safe and stable operation of the power grid. When the system is disturbed, there will be relative swings between the generator rotors, and continuous oscillations occur when there is a lack of damping. The oscillations with a frequency between 0.1 and 2.5 Hz are called low-frequency oscillations. [0003] At present, low-frequency oscillations of power systems are generally analyzed based on the response trajectory after system disturbance. Commonly used analysis methods include Fou...

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Problems solved by technology

However, the above-mentioned identification methods all need to apply incentives to the system. They can only identify the system characteristics at that time after the system oscillates and issue an alarm. early warning

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