If you live in India, you must have experience this thing that your home runs out of electricity during monsoon most of the time. Many times line men cut the power supply to prevent any damage to transformer during rains. Isolation transformers India manufacturers will explain why transformers are prone to fire during rainy season, and how to protect them.
It is not surprising to see electrical transformers catching fire and getting explode during rainy season. In the country, such cases increase in number during monsoon season. You may think about the physics behind such transformer failure that poses threat to life and assets. You should know that any short-circuit of an electric transformer would create an electric arc that has high heat energy. When electric arc is produced, the heat energy encourages oil cracking.
What is oil cracking?
When the oil produces primarily acetylene and hydrogen, this state of oil is known as oil cracking. Both the gases produced by oil are hazardous and combustible gases. However, if the manufacturing company has designed the transformer in a good way and is using quality oil with high dielectric strength then it is difficult to initiate oil cracking phenomenon. This is due to the fact that all high voltage power transformers are to be checked for short circuit once manufactured. The testing of transformer for short circuit is done as per IEE standards of short circuiting.
The transformer is short circuited and kept in same condition for minimum 2 seconds, which is sufficient to promote oil cracking. You must know that oil cracking would take around 0.1 second to happen. The unfortunate thing is that there are fewer manufacturing units having such testing facilities and only a few numbers of users specify such test while procuring power transformer.
Now coming back to the combustible gases, both hydrogen and acetylene can now exist in two forms – either as oil in vapor phase or as mist with explosive properties. The high energy of the short circuit has power to ignite these gases, which then rapidly expand and explode and result in oscillating pressure waves. The pressure of oscillating pressure waves is directly proportional to square of acceleration.
What Causes Short Circuit in Transformer?
An unwitting hawk or a crow can be a reason behind short circuit in transformer. But that alone doesn’t cause short circuit. There are other common reasons for short circuit in a transformer, such as-
Bus bar support barrier absorbs moisture from the air- this can be happen when we open up the transformer for repair and maintenance. The chances get increased if the transformer is installed at humid environment. The absorbed moisture is then compromises with the insulating property of the barrier and leads to electrical tracking that further become a reason of short circuit.
What can we do to prevent such failure and explosion in transformer?
There are few ways to protect your transformer from explosion or fire-
- Short circuit test during procurement stage
- Install transformer protector
- Install protective systems available for installation
- Regular monitoring of condition of protective devices used in the transformer
Hope this article helps you in providing protection to transformers. For queries related to maintenance, contact isolation transformers India suppliers any moment.