Trajectory eigenvalue-based system transient stability judgment and disturbance type selection method

Abstract

The invention provides a trajectory eigenvalue-based system transient stability judgment and disturbance type selection method. A state equation in an unsteady state condition, and a linear processing method for a generator, a governor, an excitation system, a network equation and load at a non-equilibrium point are studied. A higher-order linearization model for the system is built, continuous solution of the eigenvalue in the unsteady state condition is realized, a trajectory eigenvalue curve is obtained, and the trajectory eigenvalue curve characteristics are analyzed. through studying system dynamic information in the trajectory eigenvalue under load disturbance and three-phase short circuit fault, a limitation whether the real part of the eigenvalue is larger than zero does not exist, a potential law is explored, a mapping relationship among the system transient stability, a disturbance type and the trajectory eigenvalue is built, and thus, quick and accurate system transient stability judgment and disturbance type selection can be realized. Through example analysis on WSCC 3-machine 9-point, the conclusion obtained by the method of the invention is consistent with a relative power angle curve of the generator, and feasibility of the method is verified.

Description

technical field [0001] The invention relates to the field of electric power engineering, in particular to a system transient stability judgment and disturbance type screening method based on trajectory characteristic roots. Background technique [0002] The transient stability analysis of power system has always been a research hotspot in the field of power engineering. With the development of the power system, the dynamic characteristics of the system are more complex, reflecting stronger nonlinearity and uncertainty, and it is becoming more and more difficult to use the characteristic root of the equilibrium point to reflect the oscillation characteristics of the system. [0003] In the small disturbance analysis of the power system, the state matrix of the system is usually obtained by linearization at the equilibrium point, and the eigenvalues ​​of the state matrix are analyzed to judge the small disturbance stability characteristics of the system. However, the continuo...

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Problems solved by technology

However, the system at this time is at an unbalanced point, and the unbalanced power is not zero. The dynamic behavior of the system is no longer determined by the characteristic root alone, and the influence of unbalanced power must also be taken into account

The characteristic root method of the trajectory section ignores the influence of unbalanced power, and cannot accurately reflect the influence of nonlinear and time-varying factors on the oscillation frequency

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