An equivalent circuit model for partial discharge occuring in transformer oil bubbles

摘要

Bubbles may be formed in transformer oil during the fabrication, transportation and operation of power transformers. Partial discharge occurring in transformer oil bubbles is a common phenomenon as well as the reason responsible for the insulation degradation in transformers. Based on the analysis of oil bubble formation and transformation during partial discharge development process, this paper proposes an equivalent circuit model to illustrate its transient behavior and characteristics. Bubbles varied from numbers to shape may result in different wave change features. The influences of space charge, inception and residual voltages can be easily examined by adjusting the parameters in this model. The function of repetition rate, magnitude and phase of discharges behaves accordingly.