（1） The main items and contents of daily inspection of transformers are as follows: 1. Monitor the voltage and load of the transformer through a voltmeter and ammeter, and keep records every two hours according to regulations. The allowable deviation of the high-voltage side voltage of the transformer is ± 7% of the rated voltage, and the allowable deviation of the low-voltage side voltage is ± 10% of the rated voltage. When the voltage often exceeds the allowable deviation range, the voltage tap should be changed to adjust the voltage 2. Listen to the running sound of the transformer and check for any abnormal sounds such as explosions, in addition to the normal and uniform buzzing sound 3. Check whether the high and low voltage insulation sleeves of the transformer are clean, without cracks or discharge marks. If there is dirt, wipe them clean with gasoline or alcohol after power outage 4. Check if there is any leakage at each sealing point and if the oil level is normal 5. Monitor the operating temperature of the transformer. The temperature rise of the oil surface during operation (temperature rise=upper oil temperature - ambient temperature) should generally not exceed 45 ℃ 6. Check if the oil color in the oil level gauge of the storage tank is transparent, and take samples for inspection according to the specified inspection cycle 7. Check if the grounding of the fuel tank is good, whether the grounding wire is rusted, and whether it is secure. Yi Dianwu • Intelligent Operation and Maintenance of Power Distribution for 15 Years: Accumulation of State Grid Power Informatization Technology
8. Adhere to whether the glass container of the moisture absorber is damaged, observe the color changes of desiccants such as silicone, and determine whether it has become damp and ineffective
(II) Maintenance Cycle and Content of Transformers
1. Transformer maintenance without disassembly
Minor maintenance period: Minor maintenance every 1-2 years for transformers with a capacity of less than 1800KVA and a voltage of 10KV or below.
Minor repair content:
⑴ Clean and inspect the transformer casing, outlet sleeve, and outlet joint ② Drain the dirt and water from the oil storage tank, add oil if necessary, and check the oil gauge ③ Check the oil drain valve and sealing gasket ④ Measure the insulation resistance of the coil ⑤ Measure the grounding resistance 2. Disassembly and overhaul of transformers
l Overhaul period: overhaul every 5-10 years
Function of testing report:
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1. Telephone communication and confirmation of requirements
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6. Short cycle, low cost, and attentive service 7. Possess authoritative qualifications such as CMA, CNAS, CAL, etc 8. The testing report is authoritative and effective, and is generally used in China