Simulation Study of Impact of Transformer Excitation Inrush Current on Oil-fired Thermal Plants as Black-Start Sources

The oil-fired thermal plants, which are regarded as the important black-start sources in the Guangdong power grid, often fail in charging the idle-load transformers owing to the severe impacts of the excitation inrush currents. Because of the complexity of the load and the control systems, the quantitative analysis method is not suitable for this problem. In the paper, the explanation of the relevant mechanism is also provided, and the detailed model-based electromagnetic transient simulation is implemented to study the complex dynamic behaviors of oil-fired thermal plant in the preliminary stage of black-start. The simulation results show that the multi-machines and proper load connected with the generation will help reduce the impacts of transformer excitation inrush current on plants.