Research on transformer drying technology based on low-frequency heating principle

Abstract

In the process of current transformer field insulation treatment, temperature becomes the key factor to limit the treatment effect, leading to the low heating efficiency and poor effect when installing new transformers in winter. Restricted by the power of hot oil circulating heating method in the current field operation, it is difficult to improve the actual heating effect simply by increasing the power of oil filter. Based on the principle of low-frequency short circuit heating of transformer winding, a low-frequency heating device of high-power transformer winding is developed, which can be used for the insulation heating and drying treatment of large power transformers. With the method of inputting 0.2∼1Hz ac power supply on the high voltage side of the transformer and short-circuit on the low voltage side, the inductive reactance of the transformer winding is reduced, the working voltage in the short-circuit heating process is reduced, and the required power capacity is reduced, so that the device is simple, small in size and light in weight. It is proved by many field heating tests that the drying method can achieve the desired effect and greatly shorten the working cycle.