Study on the electromagnetic transient state in the new converter transformer based on coupled field-circuit method

The new converter transformer, that is the auto-compensation and harmonic-shielding converter transformer, adopts the self-coupling wiring for the secondary windings, and there is a tap at the linking point of the coupling windings, which is connected with the inductive filters. Compared with the traditional converter transformer, the electromagnetic transient state of the new converter transformer is more complex. This paper will firstly analyze the special wiring of the new converter transformer and the related inductive filtering mechanism. Based on this, the mathematical model and the simulation model will be established by the coupled field-circuit method. And then, the electromagnetic transient state under various short circuits will be analyzed and calculated. The related results will be compared with those of MATLAB/SIMULINK model to verify the correctness of the proposed simulation model and the theoretical analysis. The research works of this paper is important to the electromagnetism design of the new converter transformer.