Modeling Method for the Evolution Law of Characteristic Gases in Overheating Faults of Converter Transformers

As the power grid continues its progressive evolution, the real-time monitoring and fault prediction of converter transformers, as critical equipment in ultra-high voltage direct current (UHVDC) transmission systems, have become increasingly important. The article proposes a digital twin-based method for monitoring the operational status of converter transformers. By constructing a two-dimensional geometric model of the transformer, the oil flow circulation state in the oil channels is analyzed. Combined with the thermal decomposition equations, the evolution of fault characteristic gases with temperature changes is simulated. The method introduces dissolved gases and performs transient simulations to effectively identify discharge faults and formulate response measures. It reveals the nonlinear coupling relationship among temperature, pressure and gas concentration, providing a theoretical basis for multi-physical field modeling. Experimental results indicate that this method could monitor the operating status of converter transformers in real-time, predict potential issues, and enhance the reliability of power systems.