Detailed explanation of transformer oil degassing methods and steps
Writer： Hengfeng you electric Time：2023-04-20 views：times
1. The definition of degassing
When installing a transformer, when the gas content, oil chromatogram, or micro water of the new transformer oil or the transformer oil in operation fails, the gas in the oil needs to be removed to the qualified range. This operation is called degassing.
When the transformer oil is degassed, a vacuum oil filter is generally used to operate. When the oil passes by, the gas is gradually separated out and removed due to the vacuum effect.
Second, the method of degassing
The oil can be degassed by "moving method" or "circulation method".
1. Moving law
Pump the oil in the transformer tank through the oil filter to another tank (commonly known as the oil tank), keep pumping out the oil in the transformer tank, and then pump it in the opposite direction, so that the oil is moved away, because there is no corner oil left every time , The degassing efficiency is higher, and the degassing time can be shortened.
This degassing method requires a heavy fuel tank with a capacity of 5t or 10 or 20t, which is troublesome to carry.
2. Round Robin
The advantages and disadvantages of the circulation method are opposite to the "moving method". It connects the transformer oil to the oil filter from the lower part of the oil tank, and connects the oil return pipe to the upper part of the oil tank. Longer time
Steps:
1. The main transformer is powered off, the vacuum oil filter is connected, the oil drain valve of the main transformer body discharges the oil, and the oil enters from the main transformer oil conservator.
2. Circulate transformer oil. Before turning on the vacuum oil filter, replace the original oil filter paper with dry new oil filter paper. Turn on the heating tube of the vacuum oil filter during the circulation process to keep the oil temperature at 60-700℃, and replace the oil filter paper every 24h.
3. Make the oil level of the on-load tap-changer lower than the oil level of the main transformer before degassing the main transformer. During the degassing process, when the acetylene content of the main transformer oil is less than 2 × 10-6, replace the on-load tap-changer with new oil.
4. Sampling and analyzing the acetylene content every day during the cyclic treatment. When the acetylene content is 0.5×10-6, a full set of tests are performed on the body oil, and all data are required to be within the qualified range. The treatment can be stopped (actually after 5 days of removal The gas, acetylene drops to 0.36×10-6 before stopping.
5. Let it stand for 24 hours, deflate all parts, and do the insulation test of the main transformer. At the same time, take samples for the oil color, simplification, micro-water, and oil dielectric loss analysis test. If all the data are normal, the work ends.
6. Remove the vacuum oil filter and connect the oil pipe, and the main transformer has the conditions for commissioning (the oil level of the on-load tap-changer is lower than the oil level of the main transformer).
