Insulation oil is widely used in high voltage electrical equipment, such as transformer, oil circuit breaker, cable and capacitor. The electrical strength test of transformer oil is a main content. The sampling of transformer oil is an important step in the experiment. Transformer oil sampling refers to taking out a small part of the transformer oil for experiment. In order to ensure that the samples are not "aliasing", the experimenters must strictly abide by the sampling request and seriously stop the work.
The sampling container of transformer oil should be a wide-mouthed colorless glass bottle with a grinding plug. Its volume should be selected according to the amount of oil sampled. The amount of oil sampled should be not less than 1.2 times of the amount of oil tested and flushed, and the amount of oil sampled in the experiment of electrical strength should be 1.5Kg. Before formal sampling, the sampling container should be carefully washed with gasoline, soap and other deoiling solvents (such as alcohol, trisodium phosphate, etc.) and then rinsed several times with distilled water so that water can flow down from the bottle wall on average. The washed bottles and corks are dried in a constant temperature oven at 105 C (about 2 hours). When the temperature decreases, the corks can be tightly capped and used. A label should be attached to the sampling bottle, indicating the oil title, source, sampling date, weather, sampling personnel, etc.
1. Outdoor sampling is suitable for stopping on sunny days with low humidity to prevent other impurities such as snow and rain from intruding into oil samples.
2. Sampling in any container containing oil, transformer oil should be stationary for more than 8 hours before sampling, and sampled on the running equipment without stationary time.
3. When sampling in electrical equipment, it should stop at the oil discharge valve of the lower part of the equipment, wipe the surrounding of the oil discharge valve with clean and unhairy fine cloth, and then release 1-2 kg of oil to flush the oil contamination in the oil discharge pipeline, then release a little oil, wash the sampling container twice, and finally release the required amount of oil into the bottle and plug the bottle mouth.
4. If sampled in an oil drum, the glass tube about 2 cm in diameter can be washed and dried to stop. Before sampling, shake the oil barrel to make the oil mix evenly, then open the lid of the barrel, insert the glass tube into the oil barrel, press the top of the glass tube with your thumb, put the glass tube forward, and inject the oil into the bottle. Repeat this several times until you have taken enough oil samples. Do not use mouth inhalation tube.
1. Oil samples should represent the main oil of the equipment and should be prevented from sampling at dead corners where the oil circulation is insufficient. Sampling should normally be taken from the sampling valve at the bottom of the equipment. Sampling can be taken at different sampling sites under special conditions.
2. Sampling requirements are fully sealed, i.e. the sampling connection is reliable, the dissolved water and gas in the oil can not escape, and the air can not be mixed (the residual air in the sampling joint must be discharged), and no bubbles can be produced in the oil during operation.
3. Sampling should be stopped on sunny days. After sampling, the syringe core is requested to move freely to prevent the formation of negative pressure cavity.
4. Oil samples should be kept away from light.
5. Use 500-1000 mL sampling bottle. First stop cleaning with detergent, then rinse with tap water, and finally rinse with distilled water. After drying and cooling, close the bottle stopper.
6. For transformers, oil switches or other oil-filled electrical equipment, samples should be taken from the lower valve. Before sampling, the oil valve should be cleaned with clean grade A cotton yarn or cloth, and then washed with oil.