I've noticed that there are terms that get thrown around loosely in the industry. For example, Power and distribution transformers. What is the difference? In my opinion, transformers that step down the utility voltage down to the end user, commercial client, is what I think is a power transformer. It is my understanding that our common voltage transformers, non-utility voltages, are distribution transformers. Anyone have concrete definitions? NEC doesn't have a definition either. I've checked.
Difference Between Power and Distribution Transformers
- Thread starter E Torres
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- Placerville, CA, USA
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- Retired PV System Designer
I would turn your understanding on its head and propose instead this:
Distribution transformers fit the needs of the POCO distribution system, from substation through pole top or pad mount just upstream of the service point to customers.
Power transformers are found mainly on the customer side, and are distinguished from potential and current transformers which are used primarily for metering and protection, and control transformers which supply power inside customer equipment to convert the service voltages to whatever is required by the assorted control equipment. A power transformer delivers power to utilization equipment and may either be external to a load or included within a load to meet power needs other than just the control system.
Distribution transformers fit the needs of the POCO distribution system, from substation through pole top or pad mount just upstream of the service point to customers.
Power transformers are found mainly on the customer side, and are distinguished from potential and current transformers which are used primarily for metering and protection, and control transformers which supply power inside customer equipment to convert the service voltages to whatever is required by the assorted control equipment. A power transformer delivers power to utilization equipment and may either be external to a load or included within a load to meet power needs other than just the control system.
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Actually, it really depends upon the context and who you are discussing this with. On the Utility side, there are specific definitions for both. A "Distribution Transformer" is typically at the final end distribution point for the utility customer, what we (on the customer side) would refer to as the Service Transformer. Officially, they are limited to 10MVA and below, because it has to do with the construction methods. Above 10MVA, the transformers are used by the utilities for transforming and transmitting large amounts of power, so are called "Power Transformers". Totally different construction from Distribution Transformers.
INSIDE of a plant, at the USER end of things, "Distribution Transformer" is often used (with the term "Dry Type") to describe a MV to LV transformer such as 4160 to 480V, or higher LV to lower LV, such as 480 to 208Y120. I don't think the term "Power Transformer" is used at the end user site however, at least not commonly.
INSIDE of a plant, at the USER end of things, "Distribution Transformer" is often used (with the term "Dry Type") to describe a MV to LV transformer such as 4160 to 480V, or higher LV to lower LV, such as 480 to 208Y120. I don't think the term "Power Transformer" is used at the end user site however, at least not commonly.
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- Placerville, CA, USA
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- Retired PV System Designer
And inside of equipment (like an audio amplifier) the power transformer supplies needed voltages to the electronics taking line power as its input, and an output transformer deals with non-powerline frequency energy.
And the transformers used to tap individual speakers from a wide area 70 volt line audio source would sometimes be referred to as distribution transformers.
As jraef says, it all depends on the context.
And the transformers used to tap individual speakers from a wide area 70 volt line audio source would sometimes be referred to as distribution transformers.
As jraef says, it all depends on the context.
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Reminds me of an EE my boss hired once to help me with motor control system designs. She had no clue what she was doing, then one day she referred to all the stuff we were working on a "high voltage". It was all 120V control circuits that I had her working on... Turned out she got her degree in EE/Computer Science, but left off that last part on her application because she needed the job.
Carultch
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While there is an IEEE standard for what "high voltage" actually is, "high" still is a relative term to the uninformed. A sign may say "high voltage", even though no equipment inside is higher than 600V. If the sign were technically accurate and said "utilization voltage", the general audience member wouldn't think anything of it. But when the sign says "high voltage", regardless of the voltage that is actually inside, it gets the point across to keep your hands off of it unless you are authorized and qualified to work on it.
When one is familiar with computer science or computer systems engineering, anything greater than the 2-digit DC voltage inside a computer is "high voltage" to them.
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