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Transmission and Distribution Transformers Compared
The grid has three stages and transformers sit at each boundary. Knowing which stage you are buying for sets the voltage class, the price and the lead time.
| Transmission | Distribution | |
|---|---|---|
| Voltage | 69 kV to 765 kV | 4.16 kV to 34.5 kV |
| Job | Move bulk power long distances | Deliver to the customer |
| Transformer type | Large power transformers | Distribution transformers, pad and pole |
| Rating | Tens to hundreds of MVA | 5 kVA to 2500 kVA |
| Lead time now | Three to five years | Forty to sixty weeks, or days from stock |
| Who buys | Utilities and transmission operators | Utilities, developers, contractors |
| Cooling | Forced oil, forced air, radiator banks | Usually self cooled, no fans |
| Impedance | Typically 8 to 15 percent | Typically 2 to 6 percent |
| Installed on | Foundations in a fenced substation | A concrete pad, or a pole |
| Price per kVA | Lower, but the unit runs to millions | Higher, but the unit is affordable |
Which you actually need
Anything feeding a building is distribution. The three to five year lead times that make the news are on the transmission side, on large power transformers. Distribution lead times are bad but they are a different order of problem, and stock exists.
The three to five year lead times reported in the press are transmission class equipment, and they are genuine. Distribution transformers are also constrained but the problem is different in kind, measured in months not years, and stock genuinely exists if you are willing to pay for it.
If someone quotes you a multi year wait for a 300 kVA pad-mount, they are either quoting the wrong product or they have no stock relationship. Neither is your problem to accept.
Working from a specification that uses one of these terms loosely? Send it over and we will tell you which equipment it is actually calling for, before you order the wrong thing. Get a quote or call 786 220 2801.