Excitation current and vibration characteristics of DC biased transformer

In practical engineering, DC disturbance will lead to excitation saturation and vibration intensification on transformer core, as well as affecting the normal operation of equipment and power grid. According to the problem, a new idea is proposed in this paper. Based on the electromagnetic characteristics of DC biased transformer, excitation saturation and core vibration are studied by using excitation-vibration harmonic response analysis method. Excitation current is identified through electromagnetic coupling to characterize the excitation saturation degree. Then, vibration harmonic response model is established to analyze core vibration. Electromagnetic characteristics of DC biased Y/Δ transformer are simulated. The variation of excitation current and core vibration at different DC levels are studied. Excitation-vibration characteristics of three-phase group transformer and three-phase three-limb transformer are compared and summarized. With experimental platform built, the correctness of simulation results is verified by experimental data, and the effectiveness of the proposed method can be proved.