User talk:Nikhilesh11rkl

Oil cooling based transformers should be checked and observed daily basis. Some points are described below

1) Transformer cooling oil level 2)Transformer output voltage reading 3)Silica gel condition 4)oil and winding temperature of transformer 5)Tap position of transformer 6)Transformer load in terms of current

Oil cooled transformer maintenance (Part-1)

For residential and industrial usage oil cooled transformers are implemented .It’s from few KVA to MVA. But there not more concern about its maintenance /Preventive maintenance, but it’s very much essential to smooth maintenance and prevent sudden surprise of break down. Silica gel condition It is very much essential to check silica gel color time to time daily basis .It should be blue in color .The main purpose of silica gel is to prevent moisture to transformer oil .If percentage increases ,the breakdown voltage of oil decrease which leads to insulation fails in transformer. The moisture content in rainy season increases rapidly so we have to take care of moisture content more in rainy season than other seasons .We can reuse silica gel by heating it in a oven or removing its absorbed moisture in case of emergency. It is recommend to fill new silica gel in breather case .Daily check up silica gel to be carryout .We can change silica gel in charged transformer with the use of proper PPEs. Before doing any preventive maintenance or maintenance we must have to follow proper working procedures. If silica gel container found damaged (cracked) immediately changed the breather .If we do not change the breather then silica gel will absorb moisture more rapidly. Its recommend to change silica gel after filtration process done. When filling the silica gel in the breather take care about torque applying tightening the breather locking nut bolt.

Oil level Oil in transformer very much essential for cooling the transformer and maintain its insulation between the windings. Oil grades are different for different make transformers. We have fill proper grade transformer to a transformer. The transformer oil(in itrs) in transformers varying in terms of capacity and size. In charged condition oil level should not be below half /medium level. Always it’s prefer to check the oil level of a transformer in discharged condition .If we found low level then we have to check any leakages. We have to rectify those leakages then we have to proceed with oil filling .It is recommended to done oil top ups and filtration once in a year. In the filtration process the moisture content removing done from oil. Its recommended to check the BDV test in between the filtration process .The BDV should 65 KV and its sustain for 1 min. In the filtration process we should check the acidity of oil, any burn condition in transformer , Ratio test , magnetic balance test ,any burnt in HT and lt side , meggering /insulation test ,earth connections. Oil process filtration process duration is depends on BDV and amount oil to be filtered. After filtration done transformer should be charged after 2-3 hour after staling down of charged oil particles .After charged output voltage should be checked. Moisture Content in transformer is more in rainy season .so its preferred to do filtration process before rainy season to avoid possibilities of breakdown or insulation fail in transformer.

Oil and Winding temperature

It’s very much essential to check and maintain transformers temperature .High temperature shows the overload of transformer or any abnormalities .we can find out the oil and winding temperature by the help of analog or digital temperature indicator .Temperature of transformer must be low 80 degree c .The general temperature of winding is 2 degree more than the oil temperature .Fins are there for natural cooling of transformer .If temperature rises we can give external cooling to the transformer .We can attach a hooter to indicate excess temperature indicator .The oil and winding temperature should be taken in daily basis in the hot time of the day .If the temperature rise in low load then there may be some spark and loose connection problem in the transformer. We can take body temperature of transformer by using laser temperature sensor .Which will indicate the condition of the transformer by means of temperature. The temperature of transformer will vary from season to season ,in summer the general temperature is more compare to other season.

Tap position It is very much required to check the tap position of transformer .Tap position changes according to primary HT voltage. If tap position not changes according to primary voltage then the secondary voltage could not be properly maintained. It may be high or low. It may affect the smooth operation of m/c and lighting loads .High temperature leads to lighting load damage. If someone found tap position is wrong first he has to check the remote or local mode of oltc panel .Then he has to check the fuses is ok or not ,then he has to check the motor condition. We can change the change the tap position manually from the oltc panel. We remotely the tap not operated we can change the tap at the transformer.