A diffusion-driven model for investigating moisture effects on dielectric response measurement of transformer insulation

This paper proposes a diffusion-driven dielectric response model, which aims to reveal the effect of moisture diffusion on the dielectric response measurement of transformer insulation. In the proposed diffusion-driven model, the oil-impregnated pressboards are modeled as multiple layers and it is assumed moisture diffuses from one side of the pressboard. Then the dependency between the moisture concentration and dielectric losses and permittivity of the pressboard is studied. Subsequently, the dielectric response of the pressboard is calculated to model the dielectric relaxation behavior driven by the moisture migration between oil and pressboard. The proposed model is verified by laboratory experimental results.