Effects of Aging and Moisture on the Health Status of Transformer Oil-Paper Insulation

Power transformers undertake the task of transmitting and transforming electricity at all levels in the power grid, and are the hub of the entire power system. It is of great significance to comprehensively evaluate the remaining aging life of transformer oil-paper insulation based on multiple factors. In this report, oil-paper samples with different aging times and moisture contents were prepared to investigate the effects of moisture content and aging duration on oil-paper insulation. The accumulation and dissipation of space charges inside the samples were obtained using the Pulsed ElectroAcoustic (PEA) method. The changes in polarization and depolarization currents were measured using a triple-electrode measurement system. With the increase of aging time and moisture content, the conductivity of oil paper samples and the carrier mobility significantly increased. The accumulation of interface charges significantly decreased as the difference in conductivity between insulating oil and insulating paper decreased. Furthermore, an evaluation model was constructed to effectively assess the moisture content and aging duration of different oil paper samples based on Support Vector Machine (SVM).