Maintenance of Transformer


Transformer is static electrical machine. which is used to transfer power from one place to another place without changing the frequency. there are two different types of transformer used in electrical field. they are,

  1. power transformer
  2. lighting transformer

power transformer used for transferring high voltages from generating station to substations. power transformer is most important equipment in electrical transmission. lighting transformer is used to transfer low voltages from substation to substation in different these transformer will run long life with good performance by doing proper maintenance. there are two types of maintenance available in the transformer.

  1. Routine maintenance
  2. Periodic maintenance.

 maintenance of transformer

Routine maintenance:

The routine maintenance of transformer is common for both power and lighting we will see the routine maintenance one by one below,

  1.  we need to take the oil and temperature readings.
  2. we need to check the silica gel color in breather. if the color is blue then its ok.
  3. leakage of oil in any point of transformer it could be either main tank or conservative tank. if you found the leakage then prompt action should be taken.

 Periodic maintenance:

the periodic maintenance of transformer also common for both power and lighting transformer. there are different types of periodic maintenance is there.

  1. Monthly basis maintenance
  2. six moth basis maintenance
  3. yearly maintenance

Monthly Basis Maintenance of Transformer

Monthly basis of transformer maintenance are given below,

1. check the oil level in the tank once in a month. if the oil level is low it should added oil to maintain the oil level as per required.

2. breathing holes in the silica gel breather should be check. if it is necessary then clean the breather.

3. the transformer oil filled bushings should be visually checked the oil level inside the bushing once in a moth.

Maintenance of Transformer on six month Basis

The transformer conservator tank and main tank oil should be checked for dielectric strength once in six month. if the dielectric strength of the oil is low then oil should be replaced.

if the lighting load transformer operating in less load even in peak our then it is not required six month maintenance.

Yearly Basis Transformer Maintenance

The yearly basis of transformer maintenance are given below,

  1. the cooling systems of the transformer are  oil pumps, air fans functional should be check in once in a year. auto, manual and control circuit of the cooling systems also should be check in once in a year.
  2. The busing of the transformer at least cleaned once in a year. during cleaning time check is there any cracking in the bushings.
  3. oil condition of main tank and conservator tank should check by collecting some sample oil from the oil tank and doing the dielectric strength test (BDV test), moisture content test. if the moisture level is found high in the oil then oil should be replaced.
  4. the buchholz relay should be check once in a year.
  5. the terminal boxes in the transformers should be cleaned once in a year. and check the tightness of the cable in the terminal boxes.
  6. the space heater of the transformer should be check once in a year. if its not working properly immediate action should be needed.
  7. all the control circuit, alarm , relays and tape changer control panel are should be cleaned with appropriate cleaning agent.
  8. indicator cages should be check once in a year. whether if its required oil to be replaced.
  9. insulation resistance and polarization of the transformer should be check once in a year.
  10. earthing resistance of the transformer earth point should be check with earth clamp meter once in a year.


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