An Advanced Technique for Investigating the Moisture Effect on Next Generation Transformer Insulation Using Lightning Impulse Parameters

In this article, the effect of moisture on the next-generation insulation is investigated, and hence, the paper’s moisture content of transformer oil-paper insulating samples is estimated using the lightning impulse response parameters. For this purpose, miniature transformer insulation prototypes consisting of Kraft paper, pressboard, and so on, are developed. Then, the insulation prototypes are impregnated in the mineral oil (MO), vegetable oil (VO), or their nanofluids (taking titania or alumina as dispersing nanoparticles) considering different moisture contents. Furthermore, an experimental setup is developed to generate a standard and nonstandard lightning impulse in the laboratory. Therefore, the generated lightning impulse waves are applied to the prepared oil-paper samples, and the impulse current responses are recorded and analyzed. From this current impulse response, moisture-sensitive parameters are identified. Hence, the percentage of paper moisture content is estimated using those impulse current responses. This prediction of the moisture content in the oil-paper samples can reduce the possibility of catastrophic failure of the transformer.