Effect of Adsorption Treatment on Oil Flow Electricity of Synthetic Ester Insulating Oil

Synthetic ester insulation oil has outstanding advantages such as low carbon emissions, high safety, and high environmental protection, and has become the preferred alternative to mineral insulation oil in oil-immersed power transformers. Due to the higher internal friction, viscosity, and thermal conductivity of ester insulating oil compared to mineral insulating oil, it is bound to exacerbate the problem of oil flow electrification. In addition, the oil-paper insulation inside the operating transformer will gradually deteriorate under various factors such as temperature, electric field, moisture, oxygen, etc., generating a series of polar products that will further exacerbate the electrification of the oil flow. Therefore, this article proposes to alleviate the problem of oil flow electrification by eliminating polar products in aged synthetic ester insulation oil through physical adsorption treatment. Three kinds of adsorbents were used to study the electrostatic charging tendency inhibition effect of physical adsorption treatment on synthetic ester oil, considering different adsorbents concentration, adsorption temperature and adsorption time. The results show that compared with activated alumina and clay, 5A molecular sieve adsorbent with 5% concentration has the best improvement effect at 60 °C, which can reduce the electrification of synthetic ester oil aged at 130 °C for 20 days from 1189 pC/m to 317 pC/mL, only 32.6% higher than that of new oil, which can effectively inhibit its electrification. An effective solution is provided to restrain the electrification of synthetic ester insulated oil flow in operation.