1. Before overhauling the SF6 circuit breaker, the circuit breaker should be opened, the operating power supply should be cut off, the energy of the operating mechanism should be released, and the gas in the circuit breaker should be recovered by the SF6 gas recovery device. The residual gas must be extracted by a vacuum pump to make the vacuum degree in the circuit breaker lower than 133.33Pa.
2. The circuit breaker is filled with high-purity nitrogen (purity above 99.99%) at a suitable pressure, and then emptied, and repeated twice to minimize the residual SF6 gas and its organisms inside.
3. During dismantling and overhaul, the relative humidity of the environment should not be greater than 80%, the workplace should be dry and clean, and ventilation should be strengthened; maintenance personnel should wear nylon work clothes and hats, wear gas masks, goggles, and use latex film gloves; smoking is strictly prohibited in the workplace, and hands and faces should be washed during work breaks, and personal hygiene should be emphasized.
4. When white powdery decomposition products are found in the container during the dismantling of the circuit breaker, they should be cleaned by vacuuming or soft toilet paper, and collected in a sealed container and buried deep to prevent diffusion. Do not use compressed air to blow or other methods that make the powder fly to remove.
5. The metal parts of the circuit breaker can be cleaned with cleaning agents or gasoline. Insulating parts should be cleaned with anhydrous alcohol or acetone. Seals cannot be cleaned with gasoline or chloroform. Generally, all should be replaced with new ones.
6. Parts and seals in contact with SF 6 gas can be coated with a thin layer of HL#8 or HL#10 polytetrafluoroethylene grease. The flange surface outside the seal should be coated with neutral vaseline or #2 antifreeze grease. The imported foreign products should use appropriate grease according to the requirements of the instruction manual. Flange gaps and flange connection screws should be sealed with 703 sealant.
7. The adsorbent in the circuit breaker container should be replaced during disassembly and maintenance, and the replaced adsorbent should be properly handled to prevent the spread of contamination. The newly replaced adsorbent should be dried in an oven at 200-300℃ for more than 12 hours, and immediately loaded into the circuit breaker after natural cooling, and the exposure time in the air should be minimized. The amount of adsorbent loaded is 1/10 of the mass of SF 6 gas filled into the circuit breaker.
8. If the circuit breaker is disassembled and not reassembled in time, the insulating parts should be placed in an oven or drying room to keep them dry.