High-Impedance Transformer Parameter Determination Method for Limiting Short-Circuit Current of Power System

High-impedance transformers can reduce short-circuit currents, but they can also cause system stability problem. This paper establishes a BPA simulation model to study the influence of transformer short-circuit impedance on system stability. Through the simulation of three-phase sudden short circuit fault of the system, the influence of different short circuit impedances of high resistance transformer on the dynamic process of the system is studied. It is concluded that the high-impedance transformer has a great influence on the short-circuit current, bus voltage and power angle of the system, revealing the law of short-circuit current, bus voltage and power angle with short-circuit impedance. Through these three criteria, the general method for selecting the short-circuit impedance parameters of the transformer is obtained. In the model established in this paper, when the short-circuit impedance of the transformer is 24%, the short-circuit current can be effectively reduced without seriously degrading the stability of the system. The results of the research in this paper provide important theoretical support for the power system to limit short-circuit current.