Primary vs. Secondary Metering

[foleyspark]

Does it really pay to go primary?

You get a better rate, but now you maintain and replace the transformers...and now have to account for transformer losses...

Unless you directly utilize medium voltage, it seems that primary doesn't make sense once you factor in transformer losses bringing everything down to 480V...

Am I missing something?
Anyone have an example/analysis...

Thanks,
Mike

 

[waross]

Re the ownership of the PTs and CTs:
Revenue class meters may not be suitable for protection and vice versa.

Bill
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"Why not the best?"
Jimmy Carter

 

[EEJaime]

Another "it depends" issue is the physical configuration of the project itself. When I have a college campus, a new hospital campus, community college campus, a 100 acre automobile racing venue, a 50 acre high school campus or a several hundred acre airport to design, the project will always be a primary metered design. One can use secondary metering, but the distribution gets cumbersome, innefficient and expensive. It is much cheaper and easier to deliver 500 kVA 0f power 2000' away at 12.47kV than it is at 480V. Facilities such as these will have or will contract for maintenance services.

Just another factor that makes primary metering attractive. In some areas local utilities will offer "added facilities" service wherein they will provide on-site distribution, maintenance and metering to multiple buildings and basically finance the primary distribution system in exchange for added charges on top of the regular energy costs the facilities used. Oftentimes however, these costs when analyzed for the long run, will far exceed the costs for the customer to finance, own and maintain the system privately.

Regards,
EEJaime