DC-biasing experiment and analysis of DC-biasing characteristics based on single-phase three-limb transformer

Magnetizing characteristics of power transformer and normal operation of power grids are affected by the quasi-direct current and the direct current caused from the solar magnetic disturbance and the HVDC system respectively. In order to study DC-biasing characteristics of power transformer,a single-phase three-limb transformer is applied to carry out the DC biasing experiment in this paper. The measured magnetizing current are analyzed to study the influence of DC bias on harmonic components of magnetizing current. The iron loss are measured and analyzed under DC-biased magnetization. The measured results indicate the DC bias current has a great influence onhysteresis and excitation characteristics. The DC magnetic flux is related to the DC bias current and the excitation voltage by combining experimental results and theoretical deduction. Analysis of DC-biasing magnetizing characteristics is of great engineering significance on the safe operation of the power system,the design and manufacture of the power transformer.