桥臂复用型高压直流变压器支路短路故障分析OA

The high-voltage and large-capacity DC transformer is the core equipment supporting large-scale renewable energy transmission.As a forward-looking solution for high-capacity high-voltage DC transformers,the high-voltage DC transformer with arm multiplexing presents a significant technical challenge in revealing its fault characteristics'evolu-tion.To address the issues such as short transient duration of internal branch faults,limited electrical features,and complex coupling paths,this paper establishes an equivalent circuit model for branch short-circuit faults with AC/DC de-coupling and derives the analytical expressions for physical quantities from the fault occurrence to submodule locking.The fault characteristics of branch short-circuit faults are revealed.A comparison is made between the equivalent model and the switch model of the high-voltage DC transformer with arm multiplexing which is built on the basis of MATLAB/Simulink.Simulation results show that the proposed fault analysis method,considering the interaction coupling effects of internal branch faults,reflects the fault evolution of branch short-circuits in the high-voltage DC transformer with arm multiplexing,providing references for subsequent fault feature extraction,accurate fault identification,and rapid protection techniques.