Power system transient stability analysis method based on coupling evaluation index

Abstract

The invention relates to a stability analysis technology in the field of power systems, and aims to provide a power system transient stability analysis method based on a coupling evaluation index. Themethod comprises the following steps: establishing a space model for the state of a power system, decoupling the space model by using a coupling evaluation index and a nonlinear decoupling method, and approximately converting an original high-order nonlinear system into a series of decoupled first-order secondary and second-order secondary systems; and judging the attraction domain of each statevariable by using a low-order secondary system analysis tool, and reflecting the transient stability of the power system through the relationship between the numerical value of the state variable andthe obtained attraction domain. According to the method, different coupling pairs and isolated state variables are screened according to the coupling evaluation index and the characteristic value of the linear part and are used for guiding system decoupling. According to the method, high-dimensional and nonlinear challenges of a power electronic power system can be overcome, and compared with a traditional Lyapunov method, the method has the technical advantages that the conservative property of a result can be remarkably reduced, and then parameter design can be guided more effectively.

Description

technical field [0001] The invention relates to a transient stability analysis method of a power system based on a coupling evaluation index, that is, a nonlinear decoupling method based on a coupling evaluation index, which belongs to the stability analysis technology in the field of power systems. Background technique [0002] Most of the renewable energy is connected to the power system through power electronic devices as the interface. As the penetration rate of renewable energy in the power system continues to increase, the trend of power electronics in the power system is becoming more and more obvious. Compared with the traditional power system dominated by synchronous machines, the power electronic power system has new characteristics, mainly manifested in the low inertia of the power electronic power system, and the state variables of the system are easy to change in a large range when the system is disturbed. Thus seriously affecting the system stability, especiall...

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Problems solved by technology

However, since transient stability analysis needs to deal with nonlinear differential equations, it is much more difficult than dealing with linear differential equations

For power electronic power systems, its nonlinear and high-dimensional characteristics are obvious, and there is still no effective transient stability analysis method and framework for power electronic power systems

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