The on-site drying treatment system is mainly composed of a hot oil circulation system, a vacuum drying system and a main transformer winding insulation test system.
(1) the role of hot oil circulation system is a main transformer circulating oil heating oil heated to transfer heat to the transformer windings, the core and the insulating material, so that the body integral heat sink, so that the moisture insulating material evaporated.
(2) vacuum drying system is the role of the transformer insulating material by vacuum evaporation, and withdrawn from the transformer tank. Because moisture easily evaporates in high temperature vacuum.
(3) The function of the insulation test system is: In the insulation test, the insulation resistance and dielectric loss test are generally carried out. The dielectric loss test voltage in the oil-free state of the transformer body is controlled at about 2 kV. The measured data in the test can be For the purpose of determining the degree of dryness.
On-site drying preparation
Drying equipment such as oil tank, vacuum oil filter and vacuum pump, fire-fighting equipment in place; close the upper and lower butterfly valves of the cooler, connect the pipeline between the drying equipment, and install the temperature measuring device (installation position should be easy to monitor and record) ), connect the power supply; surround the transformer with canvas, so as not to lose heat when the transformer body is heated. Strengthen the duty and pay attention to fire prevention.
Drying process and analysis of test results
80% of the transformer oil is stored in the transformer, and heated to 90 °C ± 5 °C, then the oil is heated into the winding through the strong oil passage, while the two oil filters dehydrate the transformer oil to make the water content of the transformer oil Always stay at a low level. In this case, the insulating member, especially the water molecules in the low-voltage winding, will continuously diffuse into the oil, and the insulation performance will also increase.