In power systems, the normal operation of transformers is crucial for ensuring grid stability. However, over time or due to sudden failures, transformers need to transition from operational status to maintenance mode for necessary inspections, maintenance, or repairs. This process involves not only technical operations but also strict adherence to safety procedures to ensure the safety of personnel and equipment.
I. Preparation Stage
1. Safety Measures
- Before initiating any operation, it must be ensured that all relevant personnel have received appropriate safety training and understand emergency response measures.
- Set up clear warning signs at the operation site and implement isolation measures to prevent unauthorized access to the work area.
2. Tool and Material Preparation
- Ensure that all necessary tools, instruments, and spare parts are ready and in good condition.
- Prepare personal protective equipment (PPE), such as insulated gloves and goggles.
3. Data Recording
- For transformers about to be taken out of service, record current operating parameters in advance, including but not limited to voltage, current, temperature, etc., for subsequent comparative analysis.
II. Operational Steps
1. Power Disconnection
- Depending on the specific conditions of the substation, gradually reduce the load until complete unloading through the control system.
- Turn off the input power switch of the transformer and use appropriate locking devices to secure the switch to prevent accidental restarts.
2. Oil Drainage (for Oil-immersed Transformers)
- If it's an oil-immersed transformer, safely drain the cooling oil according to the manufacturer’s guidelines. Pay attention to handling waste oil in compliance with environmental protection requirements.
3. Testing and Inspection
- Use multimeters or other detection devices to verify that the circuit has been completely de-energized.
- Conduct a comprehensive external inspection of the transformer to identify any visible damage signs, such as cracks, leakage points, etc.
- Ensure proper grounding before starting internal inspections to avoid dangers caused by static electricity accumulation.
4. Repair or Replacement of Components
- Perform corresponding repair tasks based on inspection results, such as replacing aged or damaged components.
- All newly installed components should undergo quality inspection to ensure they meet original design specifications.
III. Resumption of Operations
1. Re-filling Oil (if applicable)
- After completing all necessary inspections and repairs, refill the transformer with the appropriate amount of cooling oil as needed and check for new leaks.
2. Functional Testing
- Prior to official resumption of operations, conduct comprehensive functional tests on the transformer to ensure all performance indicators meet expected standards.
- Monitor various operational parameters of the transformer and observe if there are any abnormal fluctuations.
3. Removal of Safety Lockouts
- Once all preparatory work is completed and the transformer returns to normal operating conditions, remove all previously set safety lockout devices.
