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Operation procedures: Starting and stopping the generator, the entire process of gas replacement, and relevant precautions. Gas replacement of the generator should be carried out after the generator’s airtightness test has been passed and its insulation meets the required standards； Gas displacement can be carried out with the rotor stationary or during barring. I. Inspections before gas displacement 1. Inspect the lubricating oil system and seal oil system of the operating turbine. 2. Conduct a comprehensive inspection of the hydrogen system to ensure that the conditions for displacement are met. 3. Shut down the circulating fan before replacement, and disconnect the on-line humidity meter and purity meter. Tools required: power supply panel, copper wrenches, claw hooks (iron wrenches and claw hooks must not be used), lighting fixtures (used to replace carbon dioxide for baking pipe valves). II. Precautions for gas displacement 1. No hot work shall be carried out in the vicinity during the gas displacement process. 2. Copper wrenches and hooks must be used; iron wrenches and hooks are not allowed to prevent the generation of sparks. 3. When working around the hydrogen system, the area must have good ventilation and adequate lighting. 4. During the displacement process, ensure that the oil-hydrogen differential pressure is automatically tracked properly; otherwise, adjust it manually. III. Gas replacement upon startup: First, replace the air inside the generator with CO₂: 1. Connect the exhaust port of the CO₂ cylinder to the manifold interface. 2. Open the generator carbon dioxide inlet door. 3. Slowly open the carbon dioxide release valve to allow carbon dioxide to enter the generator, being careful to control the inflation rate. 4. During the replacement process, maintain the gas pressure inside the generator at 0.02–0.03 MPa. 5. It is necessary to clean various dead corners, sampling doors, and oil-water detectors multiple times. When the carbon dioxide purity is ≥85%, the purity is considered acceptable, and the carbon dioxide displacement process is complete. The diagram shows: Charging with carbon dioxide: Replacing carbon dioxide with hydrogen: 1. Emptying the carbon dioxide from the generator. 2. Contact the hydrogen production station operator to determine the method for replenishing hydrogen. 3. During the replacement process, maintain the gas pressure inside the generator at 0.02–0.03 MPa. 4. Pay attention to controlling the hydrogen filling speed to prevent high-temperature spots from arising at pipe diameter changes due to excessive hydrogen flow rates, which could lead to accidents. 5. It is necessary to clean various dead corners, sampling doors, and oil-water detectors multiple times. When the hydrogen purity is ≥96%, it is considered acceptable, and the hydrogen replacement process is complete. 6. Put into operation the hydrogen dryer, circulation fan, purity meter, humidity meter, and generator insulation device. The diagram shows the gas control station: IV. Gas replacement during shutdown 1. First, replace the hydrogen in the generator with CO₂, with a purity of ≥95%; the purity meets the requirements. 2. The CO₂ in the generator was replaced with air, achieving a purity of 15%, which is within the acceptable range. 3. The shutdown and startup replacement processes are similar; it is just that the required purity levels differ for each process. V. Hydrogen replenishment during operation 1. Open the hydrogen replenishment valve. 2. Contact the hydrogen production station to refill hydrogen. 3. Adjust the hydrogen replenishment pressure. 4. When the hydrogen pressure is sufficient, contact the hydrogen production station to stop adding hydrogen; once the pressure from hydrogen addition decreases, close the hydrogen addition valve. 5. During the hydrogen replenishment process, pay attention to controlling the hydrogen addition rate. VI. Summary 1. During the gas replacement processes for starting up and shutting down, the on-line purity meter and humidity meter must be disconnected ； 2. Open-flame operations are strictly prohibited throughout the process; pay attention to ventilation ； Copper tools must be used ； 3. During the displacement process, ensure that the oil-hydrogen differential pressure is automatically tracked to remain within normal ranges; otherwise, make adjustments promptly ； 4. During displacement, pay attention to controlling the inflation and exhaust speeds ； 5. The purity must meet the requirements specified in the regulations. VII. Exam Questions 1. What are the precautions for gas displacement? 2. Hydrogen replenishment during operation? Inspections are conducted frequently.