Analysis and Experiments of Insulation Loss of Transformer Kraft Paper Based on Hotspot Variations

Abstract

The transformer plays an important role in the electric power system because it facilitates the transmission and regulation of the voltage of electrical energy. The efficient distribution of electricity from the generator to the consumer is highly dependent on the performance of the transformer, so measures are required to prevent interference. Neglecting proper maintenance can result in degradation of transformer insulation due to aging factors such as oxygen, heat and humidity. This condition produces acids and other substances which adversely affect the safety and functionality of the transformer. Therefore, it is important to determine the remaining life of the transformer. This research focuses on estimating the service life of transformers using accelerated aging experimental methods carried out in accelerated thermal aging chambers with various hot points. Temperatures of 120 ℃ and 160 ℃ were used, and the experiment lasted 30 days. This study also involved testing the tensile strength of transformer kraft paper insulation, following the guidelines outlined in IEEE C57.100 2011 which states that kraft paper insulation will achieve a loss of life if the tensile strength value is below 50% initial conditions. Analysis of the test results and conclusions revealed that the different hotspot variations had an impact on the insulating properties of kraft paper. Higher temperatures and longer heating durations result in darker coloring of kraft paper insulation and decreased tensile strength.