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Old 07-18-2019, 12:43 AM   #11 (permalink)
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Originally Posted by oil pan 4 View Post
That's such a long run it may be better to have the power company run a service lateral and use a standard residential 37kw pad transformer. But they may have a maximum limit to the length of the underground wire.
I don't think the underground part is limited in length ... but they do have line length limits from the 15KV distribution transformer to the residential pad. I think

If you have 575 volt then you already need a transformer.
We have several transformers - we do our own distribution within the plant site. I don't want to pay for ANOTHER transformer.

A residential over head high voltage to single phase is probably cheaper than an industrial 575 to 240v transformer.
To run 37kw on 4,160v they would only need to run about a 12 gauge feeder wire. So the trench, conduit ect would be small, so less parking lot to fix.
I don't think it would be reasonable to get another SaskPower (utility) feed.

Our local utility distributes residential at 14,400V (they still call it 15KV) and the transformer that they install if you don't ask for anything extra is a 200 amp service at 240 VAC. That's less than one 50 KW fast charger, isn't it?

37 kw at 4160V is still less than one fast charger. I guess I'm a bit confused?

Industrial distribution in Saskatchewan starts at 72 KV, but you are encouraged to install at least 138 KV, and we were encouraged to install 230 KV when we did our last expansion in 2012.

Our site is fed with 230KV and the site covers about 2 miles by a mile. We step the 230KV down to 15KV, and use a separate 15KV building to house our 15KV feeders that distribute to the various buildings. The 575V transformers range from 1000 KVa to 4000 KVa. We also have a few 4160V transformers that range from 2500 KVa to 6000 KVa. But I don't have a 4160V feed closer than a quarter mile. It's just not practical.

It's also a matter of economics and space. We have an existing 15KV distribution building with limited room. Our electrical group is rather protective of the 1 or 2 breakers that we have spare. If we used one, the 15KV distribution breaker, buss, metering, protection, etc are quite expensive. North of $50K per cell. And the 15KV building is a long way from the parking lot - maybe 1200 - 1500 feet.

One of our standard 15KV to 575V transformers (1250 KVA) takes some room, as well as a 15KV disconnect, a distribution panel, etc that would need to be outdoor rated and would end up taking at least 2 of the parking spots. We'd have to put fencing around the 15KV gear as well. So less parking spots, and less money for buying EV chargers. I would have 1250 KVa instead of 350 KVa ... I think that's a lose-lose scenario. Or am I missing something?

My apologies for not posting all of the relevant information for the design up front .. but my issue is that the suppliers, or the charger vendors ... won't tell me how or if their chargers talk to each other to share the available power. Can they accept 575V three phase directly? Do I need a breaker and a disconnect for each of their chargers? Somebody has this info ... somewhere ..

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