Transformer Neutral Earthing

Why the transformer neutral point connected to earth?

Showing Answers 1 - 8 of 8 Answers

1. Earth fault protection
2. Sustaining unbalanced load
3. Completing returning path of transmission line

Explaining HOW?

If single line to ground fault occurs on isolated(neutral not grounded) transformer. No return path is available so, no current will flow with this line. This will result in increase in voltage of other two line which is unfaulted. This high voltage may lead to stress on insulation and may cause of insulation failure.

At the distribution end, load to each line is not equal. If they are equal then no problem at all without neutralizing. But if load are unbalanced(most common case). Neutral current will not be 0. So, we need to provide path for it, otherwise again same problem and result in insulation failure

Sometimes, it complete the circuit through earth and we don't need extra wire to carry returning current

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jitendra bajpai

  • Jun 6th, 2012

Why Transformer rating in KVA?


  • Jun 26th, 2012

Power factor of the transformer depends on the load

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  • Jul 6th, 2012

Neutral Earthing ,
1. Protective devices reference ( eg, earth fault relay, elcb )
2. For protection transformer ( unbalanced load )
3. To maintain neutral voltage 0v ( unbalanced voltage regulation (eg,rb=415,by=406,yr=380,ne=some amount of voltage))
4. Vector line sync
5. Neon tester neutral path

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Karuppiah arumugam

  • Apr 27th, 2015

If connect like that , the neutral will work .generally the earth connected with neutral point of the distribution t/f . Then the neutral will be run to the consumer places. All distribution t/f secondary side  star connection

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suman mukherjee

  • Apr 29th, 2015

Line harmonics goes out through that wire

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Ayaz Shaik

  • Jun 29th, 2015

It does not mean always the t/f neutral is connected to ground..only in case of power t/f it happens mainly for two reasons

1) We know all things like harmonics, fault occurrence, lightning, over currents, all are suppressed

2) Power transformers are used at long transmission distances if we not connect to ground and we use another conductor creates installation cost

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  • Jul 30th, 2015

In Simple words,
There are two type of losses in a transformer;
1. Copper Losses
2. Iron Losses or Core Losses or Insulation Losses
Copper losses ( I2R)depends on Current which passing through transformer winding while Iron Losses or Core Losses or Insulation Losses depends on Voltage.
That’s why the Transformer Rating may be expressed in kVA,Not in kW.

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