When comparing oil-filled transformers to dry-type transformers in order to choose between the two, you need to look at more than just how they're built and what they cost to purchase and maintain. While your purchase decision will obviously be based on your budget, choosing the cheapest option isn't always the right move. You also need to consider your circumstances, including where you'll put your transformer and how long you want it to last before it needs to be replaced.
From a technical standpoint, dry-type transformers are better than transformers that use oil for insulation. With a few exceptions, whenever you have a choice between an oil-filled and dry-type transformer, it's usually best to go with the dry-type, and here's why.
Dry-type transformers last longer
When built with good craftsmanship, and made with high-quality insulation (like Nomex), a dry-type transformer will outlive an oil-filled transformer by many years. For example, the dry-type units made by ELSCO Transformers are especially high-quality, and the company hasn't experienced a single failure since 1988, when they began making their transformers. Their transformers also meet all industry standards, and even exceed Energy Star and DOE energy efficiency standards.
When you have the opportunity to buy from a reputable manufacturer with a strong reputation for producing quality transformers, a dry-type will provide you with little to no issues and a longer useful life.
Dry-type transformers are ideal for indoor use
Not all transformers are installed outdoors. Sometimes they need to be located inside of a building, and that's when dry-types are ideal. If you need to install or replace a transformer indoors, especially in an area where people walk nearby, a dry-type is the only safe solution.
Oil-filled transformers are prone to fires and explosions, which makes sense given that oil is highly flammable. Dry-types run cool and quiet, and pose less of a fire hazard. They dissipate heat by circulating air. They also can't leak toxic substances, like an oil transformer, so you won't need to take precautions for that potential scenario.
Although some people do it, it's not recommended to install an oil-filled transformer inside of a building. It's just too risky.
Dry-type transformers are cost-effective
When you first look at the cost of a dry-type transformer, you're probably going to think the price is pretty high. While they do cost more up-front compared to liquid-cooled transformers, you will get more value out of a dry-type. In fact, more people are choosing dry-types than ever before. The global market for dry-type transformers is expected to rise from 6.51 billion in 2024 to 10.47 billion by 2032.
Provided you have a choice, and aren't limited to an oil-filled transformer due to high voltage needs, a dry-type is worth the additional investment for several reasons:
· There's less maintenance involved
· It's less likely to fail, which means limited or no downtime for your business or clients if you're renting your property to tenants
· The installation is easy
· Dry-types can be easily retrofitted to be installed into your existing space even if you're not replacing your old transformer with an identical unit
Replacing a failed transformer is a big job and can be extremely disruptive to business, so whenever possible, choose a dry-type to avoid the hassle.
Dry-type transformers are more environmentally-friendly
If preserving the environment matters to you, and you want to choose a transformer that won't harm the planet, you want to go with a dry-type. The problem with oil-filled transformers is that the oil contains toxic chemicals, and toxic waste oil is generated throughout the process of a transformer's normal operation. For example, there are polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), toxic gasses, and heavy metals in the oil. These contaminants all have a hazardous impact on people, animals, water, air, and soil.
In addition to waste oil, the oil can soak into the ground if there is nothing underneath to capture it all.
Dry-type transformers require less maintenance
All transformers need periodic inspections and maintenance, but you'll have your hands full with an oil-filled transformer. Granted, you'll have to hire a professional for maintenance, but it will take more of your time. For instance, you'll need to have the oil tested periodically to know when it needs to be replaced since there isn't a predictable schedule like there is for your car.
Choose right from the start
Now you know a little bit more about dry-type transformers, and why people choose them over liquid-cooled transformers. However, regardless of type, a poorly made transformer won't last long, so make sure you buy from a reputable manufacturer with a verifiable track record.