Pre-Commissioning Checks Before Energizing the Transformer:

Ensure all relevant handover test documents are complete. Check the phase and color of the primary and secondary leads of the transformer are correct, and grounding connections are in good contact. The transformer should be cleaned and wiped clean, with no debris on the cover and no damage to the body and accessories, and should not contain any oil. Ventilation facilities should be installed and functioning properly, accident oil drainage facilities should be intact, and fire-fighting facilities should be complete. For oil-immersed transformers, the oil system should be open, with correct indication and normal oil level. The voltage selector switch of oil-immersed transformers should be in the correct voltage position. Protective devices should be set to meet regulatory requirements, and operation and interlocking tests should be normal.

Energizing and Commissioning of the Transformer:

1. No-load energization and impact test of the transformer. During the first energization of the transformer, full voltage impact closure can be applied, generally from the high-voltage side. After the first energization of the transformer, the duration should be no less than 10 minutes without any abnormalities.

2. The inspection method for the no-load operation of the transformer primarily involves listening to the sound. The normal operation produces a humming sound, while abnormal conditions may occur in the following situations: if the sound is loud and uniform, it may be due to a high external voltage; if the sound is loud and noisy, it may indicate loose core components; if there is a squeaking discharge sound, it may be due to flashover on the core and bushing surfaces; if there are cracking sounds, it may indicate a core breakdown.

3. Commissioning operation of the transformer. After the no-load impact test, the transformer can be operated under no-load conditions for 24-28 hours. If no abnormalities are confirmed, it can be operated under half-load conditions. After the transformer has been operated under half-load conditions and meets safety operation requirements, it can be operated under full-load conditions for 48 hours. Subsequently, the transformer temperature rise, oil level, oil leakage, and cooler operation should be checked again. Once the full-load test is passed, the handover procedures can be completed, and the transformer can be put into operation.