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the installed transformer has burned out. it is found that the replacement transformer needs a higher va rating. how can you obtain a higher va rating?

User Giraldi
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1 Answer

13 votes
13 votes

Answer:

Step-by-step explanation:

When a transformer burn out, It makes a great miss in the location, the team work has to work hard to return the power back to.

There are different factors that can cause a transformer to burn. Here we will discuss some common reasons responsible for transformer burning. But, What is meant by transformer burning? It means that the transformer actually burns out and can catch fire too, when its temperature rises to extreme level with out no cooling.

Oil Leakage

As we discussed the importance of oil in the transformer in our previous article, Similarly, oil leak is one of the main reasons that can cause transformer to burn. Oil main functions are insulation and cooling.

When the oil level falls from the standard level, the winding gets hot, and as a result the transformer temperature increases and causes burning. If the oil overheats it can also cause an explosion in the transformer.

Natural Aging

Like all other working equipment, aging is one of the failure factors. However, with a good maintenance program and well trained workers the age of the equipment can be extended. While the same equipment with no or poor maintenance makes its lifetime shorter. Transformers are not an exception, Natural aging is another reason of transformer burning. Transformer consist of Silicon coated paint having a small value of insulation resistance. Due to natural aging, the insulation resistance cannot withstand for a long time, and eddy current losses occur which causes damages to the transformer.

Also, with the factor of age, side by side to the environmental effects, the oil tank of the transformer is getting damaged due to corrosion. By this way the oil may leak and the transformer temperature rises and then, the transformer burn out.

How To Protect Transformer From Burn Out?

A good and regular maintenance program, side by side to the main protection installation from day one of transformer working are the key of protecting the transformer, Protection devices like Circuit breaker, fuses and advanced protection relays are the combination of protection system. These protection devices detect any fault before it become a serious problem and lead to burning the transformer.

We had a transformer of 2.5 MVA in the work which completely burnt out when the protection devices failed to discover and isolate the fault. The main reason was an external short circuit. The large current damaged the winding.

The following precautions need to be taken in order to protect transformer from burnout.

Regular check the transformer cooling system to make effective cooling. Check fans and oil pumps. Also check the radiator for any air blockage and make sure it is always clean.

Properly check the oil level in the transformer tank. For this purpose, monthly inspection needs to be carried out. This is why its important to have a preventive maintenance schedule.

Repair leaks, if any exist. Methods of leakage repair is i details in my other article here.

Use painting and other weather-resistive material to protect the transformer tank from aging and corrosion.

Install watchdog breakers to protect against power failure and overcurrent faults.

Make sure that protection devices and fuses are designed properly to protect this transformer.

Installing lightning arrestors can also protect transformers from burning and explosions. As it protects the transformer from lightning.

Avoiding insulation resistance, internal arcing, and reducing flashover current also help to protect transformers.

Using partial discharge devices to monitor the PD activity and detect it early before turning into an explosion.

Please 5 stars or a thanks if this helped!

User Bachsau
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