Study on temperature's impact on FDS of oil-paper insulation system by mutiple simulation methods

Abstract

Oil-paper insulation has been widely used in power equipments such as bushing, high voltage cable and power transformer. As a result, effective methods to diagnose equipment's insulation condition that in high reliability are urgently needed. In recent year, with advantages of accurate results and strong anti-interference ability, frequency domain spectroscopy(FDS) has been widely used for insulation condition diagnosis of oil-paper insulating equipment all over the world. In this paper, a new modeling method using lumped element circuit was introduced to study the effect of temperature factor on the overall broadband frequency domain spectroscopy curves of transformer, and results from XY model, finite element model (FEM) and lumped element circuit (LEC) were compared to discuss their different characteristics and the application scope. Results show that there are peaks and valleys at about 105Hz of the FDS curves got from lumped element circuit, and temperature mainly affects the amplitude of peaks and valleys. Data got from XY model and finite element model have a high consistency, but are still different in certain frequency bands. The curves of dielectric loss tangent got from lumped element circuit are quite different with the former two models. Lumped element circuit should be firstly considered when the insulation condition of transformers are assessed from multiple perspectives or with broadband curves.