In the process of transformer installation, it is very important to prevent the transformer from getting wet. The process of transformer oil treatment is closely related to preventing the transformer from getting wet. Now most of the installed transformers has a larger capacity and a higher voltage level, so it is necessary to ensure the quality of the transformer installation, and exempt from moisture contamination.
Transformer Oil Filtration Procedures
A. Preparation before oil filtration:
1. Contact the transformer manufacturer to determine the transportation method of the transformer, the total weight of the oil required for installation and the grade of the transformer oil, and determine whether the transformer oil is transported in barrels or cans. If delivery in cans, determine if the oil tank can be used on-site during the transformer installation process. According to the information of the transformer manufacturer, plan the construction site, and be equipped with high Vacuum Oil Purifier, plate and frame oil filter, oil filter paper, vacuum pump system, vacuum pump oil, oil tester , oil pipes, valves, oil storage tanks. Transformer oil pipelines and vacuuming pipelines can use reinforced PVC hoses. In order to improve the quality of transformer oil filtration, the oil storage tank should be equipped with a moisture absorber.
2. Arrange temporary power boxes, water sources and fire-fighting equipment on site.
4. If the grade of the remaining oil in the oil filtration machine and the oil storage tank is different from the grade of the new oil, the remaining oil in the Transformer Oil Purifier and the oil storage tank must be removed and stored separately. Clean the inside of the oil storage tank, keep the internal seal of the oil storage tank clean, check that the color of the moisture absorbent inside the installed moisture absorber is normal, and the oil level of the oil seal is normal.
V. Acceptance of transformer oil:
1. Each batch of new oil arriving at the site should be sampled for simplified analysis if it has been fully analyzed in the equipment manufacturer with test records. If it is the oil directly from the refinery or the commercial oil purchased by itself, or when there is doubt about the oil from the manufacturer, a sample must be taken for full analysis.
2. Sampling quantity: large tanks of oil should be sampled from each tank, and small barrels of oil should be sampled according to the table below.
3. The test standard shall comply with the provisions of the current national standard or international standards.
4. Transformer oil of different grades should be stored separately, and have obvious grade marks.
5. Visual inspection is required when draining the oil. The transformer oil transported by the tanker should not have any abnormality on the top and bottom of the oil. For the transformer oil transported in small barrels, visually inspect each barrel to identify the smell. The trademark of each barrel should be the same.
B. Oil filtration method steps:
1. When the canned oil is drained, connect the oil pipeline, the high Vacuum Oil Purifier self-circulates to heat the oil temperature, and the oil purifier cleans itself. Use the vacuum transformer oil purifier to clean the oil lines. The inside of the oil storage tank can be cleaned without transformer oil. The flushing oil should be stored separately and marked well.
2. When draining oil in barrels, use a plate-frame oil filter. Before using the plate-frame oil filter, the interior should be cleaned. The oil pipe extending into the oil drum should be made of galvanized pipe. The front end of the nozzle is processed to 45°, and the nozzles at both ends are polished smoothly. Before use, the inside and outside of the galvanized pipe must be cleaned. When the barreled oil is extracted to the bottom, check the oil quality at the bottom of the barrel. If there are many impurities, the bottom oil may not be extracted.
3. After the transformer oil arriving at the site is introduced into the oil storage tank with an oil filter, the transformer oil is filtered with a high vacuum oil purifier. In order to improve the oil filtration effect, the oil filtration of the oil storage tank should adopt the method of inverted oil filtration, that is, the oil in one oil storage tank is completely filtered into another oil storage tank through a high vacuum oil purifier, and then from the other oil storage tank. Filter into the original storage tank. If there are few oil storage tanks on site, use the oil storage tank self-circulation, and do a good job of sealing the oil tank. The outlet temperature of the oil filter should not be lower than 50℃. The filtered transformer oil should be tested with oil samples to determine whether the transformer oil is qualified for purification. Oil samples can be taken from the oil filter sampling valve.
C. Notes on transformer oil filtration:
1. The transformer construction area should be fenced with warning signs.
2. Fireworks are strictly prohibited in the transformer construction area, and sodium carbonate dry powder fire extinguishers are provided on site.
3. Before filtering oil, check the reliable grounding of all equipment and components.
4. Detailed technical disclosure and safety disclosure should be made before construction. Construction personnel should be familiar with equipment operation and construction procedures.
5. When the oil pipeline is connected, it must be tied firmly to prevent oil leakage and oil running.
6. During the transformer oil filtration, the on-duty personnel should inspect the equipment status and oil system status, and make records.
7. When receiving the incoming oil, calculate the total amount of incoming oil, allocate the flushing oil and installation oil, try to avoid wasting oil, and ensure that the transformer is filled with oil at one time.
8. Oil inspection is an important part. Since there is no better on-site inspection method at present, it can only rely on the visual inspection and smell of the on-site personnel to make judgments. This work should be carried out by experienced construction personnel.
9. During the transformer oil filtration process, the inlet door of the oil storage tank should be sealed with a plastic sheet. The bottom of the installed moisture absorber should be filled with enough oil according to the scale line.
10. The oil temperature at the outlet of the oil filter should be at least 50°C, and the highest should not exceed 70°C.
11. Pay attention to observe the oil quality of the vacuum pump of the oil filter, and replace the vacuum pump oil in time.
12. Pay attention to observe the oil level of the oil accumulation window of the oil filter, and stop the machine to drain the oil in time.
13. Pay attention to the pressure gauge at the outlet of the filter screen of the oil filter, and replace the filter screen in time.
14. When the oil pipe is not in use, it should be tightly sealed with plastic cloth immediately to prevent moisture and impurities from entering the pipe.
15. After filtering the oil in the oil storage tank, seal each outlet of the oil tank tightly with a plastic sheet in time.
16. Before the oil filter heater is put into operation, it must be confirmed that the oil level of the oil filter is normal. Before shutting down the oil filter, turn off the heater. Prevent the heater from burning empty and damage the equipment.
The measurement of trace water in insulating oil shall meet the following requirements: the trace water content in transformer oil shall not be greater than 20ppm for voltage levels of 110kV; for 220-330kV, it shall not be greater than 15ppm; for 500kV, it shall not be greater than 10ppm . The measurement of the gas content in the insulating oil shall meet the following requirements: For a transformer with a voltage level of 500kV, the gas content in the oil shall be measured by sampling before the insulation test or the first step-up, and the value shall not be greater than 1%.
Add：1 Xinmao Road, Beibei district, Chongqing, China