Constant-Parameter VBR Modeling and Analysis of Synchronous Generators Considering Magnetic Saturation Characteristics
Traditional electromagnetic transient simulation of synchronous generators suffers from insufficient numerical stability, low computational efficiency, and inadequate representation of magnetic saturation. To improve the reliability of power grid security and stability analysis, this paper proposes an improved modeling scheme based on the voltage-behind-reactance (VBR) method, focusing on the performance deficiencies of conventional current-source equivalent models. The scheme constructs a decoupled machine-network interface circuit with constant resistance-inductance branches via constant-parameterization, employs piecewise linearization of the flux-current characteristic curve to accurately represent magnetic saturation, and adopts a hybrid explicit-implicit Euler discretization to avoid algebraic loops. Validation on a single-machine infinite-bus benchmark and fault condition tests on the IEEE 14-bus system using MATLAB/Simulink demonstrate that the proposed model significantly enhances computational efficiency and numerical stability for large-step simulations while maintaining excellent accuracy in fault transient scenarios. Compared with the MATLAB/Simulink SPS model, the proposed model achieves a 55.6% improvement in computational efficiency under equal simulation accuracy, with two-norm voltage errors of 0.33% and 0.3% at nodes 5 and 9, and current errors of 0.51% and 0.41%, respectively. The model is suitable for large-scale electromagnetic transient simulation analysis of power systems.