AC/DC system stability domain analysis method based on quadratic sum decomposition optimization algorithm

Abstract

The invention discloses an AC/DC system stability domain analysis method based on a quadratic sum decomposition optimization algorithm, and the method comprises the steps: building an AC/DC hybrid power system mathematic model for transient stability analysis through considering the control state switching characteristics of a DC converter; converting a stable balance point of the mathematical model of the AC-DC hybrid power system to an original point by utilizing the stable balance point solved by load flow calculation; converting a trigonometric function in the mathematical model of the AC/DC hybrid power system into a polynomial so as to be suitable for a quadratic sum decomposition optimization algorithm; and according to the Lyapunov stability theory and the alternating-current and direct-current hybrid power system mathematical model, solving the stability domain of the alternating-current and direct-current hybrid power system in each control mode by utilizing a quadratic sum decomposition optimization algorithm. The method provided by the invention is suitable for a power system with higher dimension and stronger nonlinearity, can be used for analyzing and evaluating influence factors of transient stability, and is beneficial to transient control and parameter optimization of the power system.

Description

technical field [0001] The invention relates to the technical field of transient stability analysis of AC and DC power systems, in particular to a method for analyzing the stability domain of AC and DC systems based on a square sum decomposition optimization algorithm. Background technique [0002] In recent years, with the increase of DC transmission, the dynamic characteristics of the AC-DC hybrid system have changed greatly compared with the traditional AC system. The complex structure of the DC system, the interaction of each dynamic component under multi-time scale control, and the topology changing with the control switching make the transient stability analysis of the highly nonlinear AC-DC hybrid system more complicated. In addition, different control modes and combinations of DC rectifiers and inverters have different effects on stability. Therefore, more accurate methods are urgently needed to analyze and evaluate the transient stability of AC-DC hybrid systems, an...

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Problems solved by technology

However, the commonly used methods based on energy functions and dominant unstable equilibrium points are relatively conservative, and it is difficult to analyze power systems with large transmission conductance and voltage-dependent active loads. In the results, the DC system is often expressed as a quasi-steady-state model, and the entire system is described by a unified Lyapunov function. The stable region is only solved in the space of state variables such as bus voltage, phase angle, and generator, and the parameters that reflect the dynamic characteristics of DC are ignored. The influence of key state variables on the stable domain of the system, it is difficult to evaluate the influence of the DC converter control mode and switching characteristics on the stable domain

However, how to retain the characteristics of the DC system with a flexible and convertible converter control mode, and quantitatively analyze the impact of this feature on the stability of the AC-DC system from a domain perspective is a difficult problem

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