Primary fed transformer 1

[itsmoked]

Does anyone have any experience with putting in an owned transformer directly fed by a PG&E primary service (24kV)?

What would be the typical process for doing this?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[cranky108]

I would think they would expect you to have staff trained to work on the distribution voltage level.

 

[stevenal]

Link

 

[itsmoked]

cranky108; Nope. Not from what I've seen. The POCO deals with that side of the transformer the customer deals with the LV side. If you need to mess with the LV side on the transformer side of the main secondary breaker the POCO pulls the cutouts for you.

stevenal; THANKS!! Didn't even think to look for a PG&E document on it.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[bacon4life]

My local observation (e.g. not PG&E) is that relatively few primary metered customers have staff qualified for working on primary voltage equipment. I wish I could require primary metered customers to have consulting contracts set up with appropriate electrical contractors and equipment suppliers. In reality, many of the primary metered customers do not proactively plan for maintenance/replacement of the medium voltage equipment. Often the primary metered customers do not even seem to understand that being primary metered means that the utility does not fix any of the customer owned equipment. When something eventually fails, the customer could be out for long periods while they wait for spare parts or attempt to hire qualified electricians.

Sometimes prospective customers look at the rate difference between primary service and secondary service, and then incorrectly conclude that primary service is much cheaper. Although primary service results in a cheaper monthly utility bill, it comes with lumpy replacement costs as well significant reliability risks.

 

[cranky108]

Many of our primary metered customers are data centers, that are willing to pay for an alternate feed, and backup generation. Also, I don't know of many cases where we would not help such a customer when in need.
That said, I have seen help turned down to primary metered customers who need help in too many cases. Those are the same ones that would purchase used equipment, and equipment that barely met the requirements.

Some primary metered customers do have contracts with qualified people to do the work for them. Others have staff that are trained (line people).

 

[catserveng]

Keith, yes can be done, you drive past one every time you go to the dump.

But PG&E does not make it easy, first off, use a local engineer with existing experience with PG&E, I have done a couple jobs up there where the end user decided to use "their" engineer, and in both cases had to end up going with a local engineer who was known and experienced with the utility.

They will be very stringent on your protection, both design and testing, sometimes what you may think is beyond what a utility would put you thru. My experience with PG&E has always been difficult, but if you follow the standards, be clear on what you want to do and have all your ducks in a row the first time around it makes life way easier. What will bring your project to an absolute crawl is asking the PG&E engineers how to do something, have seen it in action way too many times. In the past they have been very clear they are not there to help you design your project, they are only there to approve what you propose.

Is the site going to have generation of any kind, or just a service? If it has generation, be prepared to also have to deal with the requirements defined here,

https://www.pge.com/en_US/large-bus...istribution-handbook.page?WT.mc_id=Vanity_dih

My experience in their area has mostly been with landfill and digester gas engine generation, which in most cases they didn't want to deal with anyway.

The link Stevenal provided indicates there are recommended inspections and tests that are not required, but in all the jobs I've done up there the local inspectors did require those checks to be performed and documented per NETA/ANSI standards.

Hope that helps, MikeL

 

[itsmoked]

Thanks Cranky. That compares well to Cat's guidance.

That did help catserveng. Considerably, and with local knowledge! All points noted, many thanks.

No generation. Main issue is that Santa Crux has become far less industrial, backing everything into 'commercial' which results in quite old 480V installations with some fixed service like 200A. Anything new is 200A, 320A, 400A, and that's at 208V!

This customer has ordered 400hp and 250hp machines to complement their existing 125hp and 20hp machines! This all adds up to about 900A @ 480V and doesn't include all the ancillary loads. Reasonable would be a 1200A 480V service or 3/4MW. This means no 208V place will ever cut-it. Asking PG&E to "upgrade this service to 1200A @ 480" takes them years because someone there has to break out a calculator and do 30 minutes of work.

But, if you show up with a completed design that requires them to bring over 10AWG from some cutouts to an in-place pad mounted transformer it seems to be much much faster service.

 

[stevenal]

I think you'll need a primary metering cabinet in front of that transformer. Note that transformer losses are metered.