Method and device for identifying subsynchronous oscillation and super-synchronous oscillation of power system

Abstract

The invention provides an identification method and device for subsynchronous oscillation and super-synchronous oscillation of a power system, and the method comprises the steps: building an analysis model based on an oscillation signal of the power system, and the analysis model comprises a fundamental wave sine component, and a pair of subsynchronous sine component and super-synchronous sine component which are coupled in frequency; decomposing the fundamental wave sine component into a positive frequency fundamental wave sine component and a negative frequency fundamental wave sine component, and respectively synthesizing the subsynchronous sine component and the super-synchronous sine component into a positive frequency oscillation component and a negative frequency oscillation component; constructing a synchronous phasor spectrum fitting equation set, and weighting the spectrum error based on the synchronous phasor sequence after Fourier transform; and solving the synchronous phasor spectrum fitting equation set by taking the norm of the weighted spectrum error as a target to obtain a positive frequency fundamental wave sine component, a negative frequency fundamental wave sine component, a positive frequency oscillation component and a negative frequency oscillation component, and determining the frequencies, amplitudes and phases of the fundamental wave sine component, the subsynchronous sine component and the super-synchronous sine component.

Description

technical field [0001] The invention relates to the technical field of power system wide-area monitoring and sub-synchronous oscillation, in particular to a method and device for identifying sub-synchronous oscillation and super-synchronous oscillation of a power system. Background technique [0002] Oscillation is one of the most common disturbance processes in power systems. Serious oscillation will lead to system instability, line overload and other problems, which will seriously threaten the security of the power grid. Therefore, when the oscillation process occurs in the power system, it is necessary to effectively monitor and identify the parameters of the oscillation. Since the power system is an AC power system running at the rated frequency, when oscillation occurs, the oscillation signal mainly includes the fundamental sine component offset from the rated frequency, the sub-synchronous sine component whose sum of frequencies is twice the rated frequency, and the su...

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Problems solved by technology

[0004] The existing power system oscillation identification methods based on synchronized phasors are all based on Fourier transform spectrum analysis. Therefore, a larger data window has to be used to avoid spectrum aliasing, resulting in poor real-time performance of oscillation identification; furthermore, poor real-time performance of oscillation identification will lead to poor identification results, because the larger the length of the data window, the greater the power system’s The more likely the oscillation mode is to change, so some scholars propose to use nonlinear overdetermined equations to calculate the oscillation parameters. The amplitude, phase and frequency of the frequency offset fundamental sinusoidal component, subsynchronous sinusoidal component and supersynchronous sinusoidal component within times of the rated frequency, but this method establishes a time-domain synchronized phasor trajectory fitting equation set, in the It is difficult to control the solution accuracy of oscillation parameters when the goal of nonlinear curve fitting is to minimize the error in the time domain, resulting in low accuracy of oscillation parameters

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