Research on Incipient Fault Monitoring Technology for Oil-immersed Power Transformers Based on Dissolved Gas Dynamics Analysis

To enhance the accuracy of latent fault monitoring in transformers, a multi-point DGA monitoring location selection method based on kinetic analysis of dissolved gas diffusion in insulating oil is proposed. First, molecular dynamics simulations are performed to derive fitting equations for the diffusion coefficients of seven types of fault gases in insulating oil under varying temperatures, revealing microscopic diffusion mechanisms. Subsequently, a fluid-gas transport dynamics model is developed by coupling Fick's diffusion law with modified Navier-Stokes equations within a two-dimensional converter transformer structure. This model simulated hydrogen diffusion patterns under different fault locations. Results demonstrate that high-flow-rate zones exhibit wide-range gas distribution dominated by convective diffusion, while low-flow-rate areas show localized gas accumulation due to prominent Fick diffusion effects. Ultimately, by superimposing steady-state spatial concentration distributions of hydrogen released from six preset fault sources, regions with peak integrated gas concentrations are identified. This analysis determined five optimal monitoring points(P1~P5). This research provides theoretical support for multi-point collaborative DGA monitoring in transformers from the perspective of dynamic gas transport, significantly contributing to early detection capabilities for latent faults.