Transformers play a more crucial role in our power system than one might have imagined. It is through the use of transformers, that we have been able to transfer current to different places successfully and safely. We should not only reap the benefits of using transformers but also make efforts to maintain the transformers so that they stay in top condition and provide maximum efficiency and productivity.
Don’t we often we a big bang and all of a sudden lights go out for at least half a day?
And we are left in the dark wondering what happened!
Pretty much every one in Nepal has faced this problem at least for once. This is a very common problem that arises due to the failure of the transformer system. If we don’t want to face this annoying problem, we should know a thing or two about taking care of transformers, how problems arise in transformer system and its preventions.
Transformers are one of the most reliable, long lasting and sturdy electric devices. These vastly useful devices require less care and attention compared to most electric devices. However, if no care and attention is given, transformers become prone to failure due to many internal and external factors.
Common causes of transformer failure:
Age of transformer:
Just like everything else, transformer’s age is also a relatively important factor when it comes to determining potential issues in case of a failure. Any transformer 15-20 years old is considered to be relatively old and might be more susceptible to damage due to daily wear and tear.
Mechanical Failure:
Mechanical failures is one of the most common reasons why transformer failures occur. Mechanical failures can happen due to any reason. Shipping damage, seismic activities or any thru-faults results in default mechanisms in transformers. When this kind of failure occurs, winding turns may be displaced or damaged. Mechanical failures often result in the beam failures. Hence it is highly recommended and would be thoughtful to perform SRFA tests to check if the transformer is working properly or not.
If your transformer starts showing indications like changes in low voltage excitation current, change in impedance or presence of partial discharge during voltage tests, then these defects are caused moreover due to the mechanical failures which are a result of mechanical deformation.
Electrical Failures:
Electrical problems often are one of the most common reasons behind the problems arising in transformers. In most cases, electrical failures are the result of insulation degradation. This is often caused due to the thermal degradation due to the presence of excessive fault currents in the system. Transformers should be prevented from high voltage stress to prevent such problems from arising.
When transformers become excessively hot, the insulation breaks down and becomes brittle over time. After thermal aging happens, the transformer becomes vulnerable when fault current passes as they might mechanically shake up the windings, form crack in insulations and even internal transformer faults may appear. Electrical failures are often seen during diagnostic tests. These tests need to be conducted frequently as they will even give clues as to where the defects are in the system.
Failure based on construction:
Shell form construction is resistant to winding deformation due to the thru-faults. It is because the coli “pancakes” are arranged in multiple groups. The area vulnerable to damage is the edge where windings are connected together. The most common way in which this problem can be prevented is by providing adequate support in the outer turns.
Even the core form construction of a transformer can also result or exhibit failure in multiple ways. Radial tension failure or radial compression failures can occur in the inner windings of the transformer. To prevent this, a strong winding support structure needs to be placed. Axial failures often result in a tangled mess of conductors which disrupts the force vectors in ways that were not accounted in the original design.
Inconvenient craftsmanship:
The level of craftsmanship is one of the most important factors that helps us to estimate the life of a transformer. The quality of manufacturing process and controls placed drastically impacts on how the transformer performs. Unfortunately, this part is often overlooked and we get stuck with lower quality and vulnerable transformers.
Material and Design:
Better the quality of material used, the better the quality of transformer. It is as simple as that. The use of right wire and insulating materials makes enormous difference in how efficiently the transformer works. It is also essential to use the right material for the iron core. According to researches, silicon steel with thin thickness is one of the best materials for constructing transformers.
Design of a transformer also plays a vital role in estimating the potential life of the transformer. Round and wound designs are usually preferred as they reduces the voltage stress, does not create much noise and also helps the transformer to stay cool. With this design, even the short circuit risk is reduced.
Loose connections:
Loose connections may need to be checked frequently as presence of loose ends may lead to excessive and unnecessary buzzing and overheating issues. Loose connections may often appear as a result of long term vibrations in the transformer system.
Overloading issues:
It is important to know that overloading rarely causes transformer failures. But the problem that occurs along with overloading is the thermal aging of winding insulation. Presence of unbalanced load in the power system causes high temperatures in the systems which results in local heating.
Excessive harmonics and cooling issues:
When higher temperatures is observed on neutral termination, this generally indicates presence of harmonics in the system. In general, the harmonics on third and fifth level indicates interference from electronic loads which affect the system.
Cooling issues also need to be solved as they affect the working of the transformer. This should be thoroughly checked and cooling fans may even need to be changed if they are out of order. Leakages inside the system also need to be checked as this results in the increase of temperature inside the system.
If you are looking for the best transformer in Nepal, you can always contact BN Mahto Group. We are the top transformer company in Nepal and have been providing the top quality products to our customers for decades. The transformers produced by us has a good reputation in the market. With great pride we say that our products get good reviews and our customers are not just satisfied, but happy with us and our services.