Simulation study on transient operation and bypass protection of a single-phase conventional hybrid transformer

Abstract To address the limited voltage regulation capability of conventional power-frequency transformers and the vulnerability of the power electronic branch in hybrid transformers to transient stresses, this paper studies a single-phase conventional hybrid transformer and establishes a 3 kV/100 kVA hybrid transformer model in MATLAB/ Simulink. Typical operating conditions, including steady-state operation, sudden load changes, input voltage sag and swell, and fault bypass, are configured to analyze the output voltage regulation capability and transient operating characteristics of the hybrid transformer. The simulation results show that the power electronic branch can provide compensation voltage under input voltage fluctuations and load disturbances, maintaining the output voltage near its rated value. When a system fault occurs, the bypass protection branch can rapidly remove the power electronic compensation path, thereby reducing the impact of fault transients on power devices. The results can provide a reference for simulation modeling and protection strategy design of hybrid transformers.