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What Causes Transformer Explosions and Burns?

The likelihood of a transformer exploding and then burning is quite low; however, it’s not impossible. And that’s because the firewall barriers installed on transformers are highly efficient in reducing the likelihood of explosions and fires. However, there are cases where transformers blow and burn. In most of these cases, the transformer explosions and burns often result in injuries, deaths, property damage, and electric failure that could last for weeks.

The Main Cause Of Transformer Explosions And Burns

Electric transformers are responsible for transferring energy between different circuits while switching energy from one voltage to another. However, due to accidents or faulty mechanisms, there can be a sudden surge in voltage levels, and when the transformer is flooded with too much electricity, it explodes and burns. 

Reasons For Transformer Explosions and Burns

The most common reason why transformers explode and burn is accidents caused by lightning strikes. Lightning strikes can often damage the wiring and transformer equipment. Other extreme weather conditions such as strong winds and rains can cause trees to fall on transformers, causing explosions.

When damage occurs in a transformer, two things may occur. The first is an overload in the supply of electricity flowing into the transformer. And the second is the overheating of insulation fluid (mineral oil) past its flash point or fire point.

Aside from accidents, another reason for transformer explosions and burns is an electrical failure, which can be caused by poor insulation, static electrification, over-voltage, partial discharges, and power surges. Mechanical failure caused by conductor telescoping, conductor tipping, or hoop buckling can also lead to explosions and fires.

How Do Transformer Explosions and Burns Happen?

As you’re aware, electricity is a source of heat. And in transformers, the amount of electricity passing through can generate tremendous amounts of heat. So, to increase the lifespan of the transformer, insulation is required. And the most common insulant used in transformers is insulation liquid.

The insulation liquid commonly used is petroleum-based mineral oil. The mineral oil is supposed to absorb the excess heat to protect the mechanical parts of the transformer. When selecting an insulation liquid, experts usually consider the liquid’s fire point and flashpoint. The fire point of mineral oil is 165°C, and the flashpoint is 145°C.

However, when there is an overcharge, temperatures increase, leading to the decomposition and vaporization of the mineral oil, resulting in gas bubbles. The gas bubbles are usually made of vapor, hydrogen, and methane, a highly combustible combination. As temperatures continue to rise, the mineral oil will reach its flash point and ignite the vapor-gas mixture. And a further increase of temperature to the mineral oil’s fire point will now facilitate combustion on the insulation liquid’s surface.

Combustion of the liquid will lead to an increase in pressure. The high pressures will force the transformer to rapture, and the result is an explosion, which releases high levels of energy and strong thermal radiation, and flaming oil. 

While it’s difficult to determine whether or not a transformer explosion will occur, you can avoid the collateral damage associated with these explosions. With our transformer fire barriers, you can reduce the structural and environmental impact of transformer failure. If you want to learn more about how we can help you, visit our website via this link and check out our high-quality products.

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