1. Preventing Oil Leakage: Oil-immersed transformers are filled with transformer oil in the tank, and are sealed by fasteners pressurizing the oil-resistant rubber components during assembly. Poor sealing is the main cause of transformer oil leakage, so special attention should be paid during maintenance. Check if small bolts have loosened due to vibration; if so, tighten them appropriately and consistently. Check if the rubber is broken or severely deformed. Replace the rubber parts if necessary, ensuring they match the specifications and keeping the sealing surfaces clean.
2. Preventing Transformer Moisture: Transformers are high-voltage devices requiring good insulation. Oil-immersed transformers are highly susceptible to moisture; preventing moisture is one of the main maintenance measures. Users should note the following: After purchasing the transformer, immediately request the power supply bureau to conduct a handover test; immediately install a dehumidifier. Transformers with a capacity of 100 kVA and above are equipped with dehumidifiers. Once the transformer arrives at the site, immediately install a dehumidifier to prevent the internal components from becoming damp. Monitor the silica gel in the desiccant; replace it immediately if it becomes damp. The silica gel in the desiccant absorbs moisture and protects the transformer. Once saturated with moisture, the silica gel will change color, at which point it needs to be replaced with new, dry silica gel. When ordering, pay attention to minimizing the storage time before energizing the transformer. Transformers are highly susceptible to moisture absorption after manufacturing, and the longer the storage time, the more severe the moisture absorption. Therefore, plans should be made to shorten the storage time as much as possible. Small transformers with a capacity of 100 kVA and below do not have desiccant devices. The oil in the oil conservator is prone to moisture absorption, leading to water accumulation. If a transformer has been stored without energizing for more than six months, or has been in operation for more than one year, the oil in the transformer oil conservator will be severely damp. Before lifting, transporting, refueling, draining oil from the oil valve, or lifting the core, the dirty oil in the oil conservator should be drained through the drain plug under the oil conservator, wiped clean with a dry cloth, and sealed to prevent dirty oil from entering the oil tank. During transformer operation, it is essential to frequently monitor changes in oil level, oil temperature, voltage, and current. Any abnormalities should be analyzed and addressed promptly. During transformer installation, it is strictly forbidden to connect aluminum stranded wire, aluminum busbars, or similar materials to the transformer's copper conductors, as this can corrode the conductors.
3. Transformer Oil Change and Drying: Prolonged idleness, extended operating time, or other natural or human-caused factors can lead to decreased insulation, internal water ingress, or oil deterioration. In such cases, oil change and drying are necessary. Transformer Oil Change: First, remove the transformer body, drain the dirty oil, and clean the oil tank. If there is oil residue on the body, rinse it thoroughly. After the body is dry, inject new oil and replace all oil-resistant rubber seals. The transformer can only be put into operation after passing a test. Transformer Drying: There are various methods for drying the transformer body. Users can use zero-phase sequence drying, eddy current drying, short-circuit drying, or oven drying. For larger capacity transformers with a voltage of 35 kV, it is best to send them to the manufacturer for vacuum drying. This ensures that the transformer insulation is thoroughly dried without causing it to age.