Calculation Method for Arc-Induced Gas Generation in Transformer Oil Considering Electric-Field Coupling

Based on the arc-induced pyrolytic gas generation process in real oil, this study establishes a mechanistic fluid-dynamics model for characterizing the pressure source. A mixed system of butane and propane is used to replace the complex system of transformer oil, and the changes in the mass of gas components caused by thermal decomposition reactions are written into the continuity equation as a mass source term. Second, the electric-potential equation is introduced, and Joule heating is taken as the energy source to drive the occurrence rate of thermal decomposition reactions, i.e., the gas generation rate. Finally, using the on-load tap-changer (OLTC) oil compartment as a case, the obtained motion of the gas cluster during arc discharge and the resulting pressure fluctuations are consistent with the overall waveform and amplitude described in the literature. The model proposed in this paper reduces the dependence on empirical gas yield and provides a basis for quantitative calculation of gas production and pressure loading under extreme operating conditions.