Oil Level Check and Maintenance: The oil level should be maintained between 1/4 and 3/4 of the mark on the oil level gauge (refer to GB/T 6451-2015 standard). If the oil level is too low, it may lead to insufficient insulation or overheating; if it is too high, it may easily cause abnormal oil pressure.
Check Method: Observe using a transparent oil level gauge or a magnetic oil level gauge. This should be done when the transformer is powered off and the oil temperature is stable. In winter, the oil level may drop by 5% to 10%, which is normal (Source: IEC 60076-7).
Oil Quality Testing and Replacement: Take samples for testing at least once a year, checking the breakdown voltage (≥35kV), moisture content (≤20ppm), and acid value (≤0.1mg KOH/g). If the levels exceed the standards, the oil needs to be filtered or replaced.
The oil replacement cycle is usually 8 to 10 years (adjusted according to the operating environment). New oil must meet ISO 60296 standard.
Temperature Monitoring: The top oil temperature must not exceed 85℃ (natural cooling) or 95℃ (forced cooling), with a temperature rise limit of 55K (as specified in DL/T 572-2021).
Regularly clean dust from the radiator surface to ensure good ventilation.
