A Method for Thermal Ageing Condition Assessment of Mineral Transformer Oil Based on Three-Dimensional Fluorescence Spectroscopy

Power transformers are the core equipment of electrical power conversion and transmission in a power system, and the optimal condition of the insulation system is crucial for its reliable operation. The insulation system gradually deteriorates under the influence of thermal stress during operation, causing the insulation and cooling efficiency to decline. Aiming at the ageing of mineral transformer oil caused by thermal stress, a method for ageing condition assessment based on three-dimensional fluorescence spectroscopy is proposed. The approach extracts and models the position deviation and intensity variation of the maximum peak of the three-dimensional fluorescence spectrum. Accelerated thermal ageing experiments were conducted on mineral transformer oil under laboratory conditions, with regular collection of three-dimensional fluorescence spectra. Experimental results show that the proposed method has a strong correlation with ageing time, and is more sensitive than interfacial tension and UV-Vi absorption spectroscopy.