Maintenance of power transformers
An oil sample tests - pressure, impurities and other performance indicators every three years time, power transformers, long-term full load or overload operation can shorten the cycle.
2, high and low voltage insulation resistance of not less than 70% of the original factory settings (10MΩ), the DC resistance of the windings at the same temperature, the phase difference between the average value should not exceed 2%, and the results of the last measurement should not exceed 2%.
3, the power transformer grounding resistance value measured once every two years.
4, blackout cleaning and inspection cycle, determined according to ambient and load conditions, generally six months to one year; main content remove the defects found in inspections, cleaning, cracking or aging of porcelain bushing shell replacement pads, the connection point tighten the check, the lack of oil and f ill oil respirator silicone check and replace.
The grounding of the power transformer
A power transformer enclosure should be reliably grounded, the zero line and neutral grounding wire should be laid to the zero line of work can not be buried in the ground.
2, the power transformer neutral grounding circuit, near the power transformer, it shall be made detachable connection bolt.
Equipped with surge arresters, transformer grounding shall meet the requirements of the Trinity; neutral point of the power transformer, power transformer housing arrester ground should be connected in a common ground.
4, the grounding resistance should be less than 4 ohms.
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