CHP interconnection & 705.12(D)

[emerkel]

Hey all, usually a PV guy but working on some light CHP project feasibility evaluations. I'm very familiar with how 705.12(D) applies to PV and I can't seem to find a definitive answer of whether this rule applies to the other technologies. Seems like it should though not all technologies use inverters ("utility interactive inverter" is specifically called out). I'm thinking all the same rules apply but am curious in everyone else's take on interconnection of non-backup ('baseload' DG) engines/microturbines/etc.
Thanks!
Evan

 

[starbolin]

What state would this be in?

I get stuck reading as far as 705.4 Equipment Approval - 'All equipment shall be approved for it's intended use...'

Has the AHJ adopted rules that would allow the HP equipment or, under the AHJ in question, are HP systems individually approved? ( Or ever approved at all? )

As far as 705.12(D) the section allows approved UII's to be connected to the load side of the disconnect. If you got anything else then you gotta find an article or section that allows it. Maybe in Article 685?

 

[emerkel]

Thanks for the reply, it's in several different states with adoption varying from '08 to '14 so not a lot of help there.

We're still at the high level so AJH hasn't been consulted, though that's likely what would resolve the issue when the project got close enough to need to contact the AHJ.

I interpret 705.4 as just needing to be listed to its appropriate UL listing, not approvals from AHJ (though that's important too!)

I somewhat agree with your interpretation of 705.12(D) and that gensets that don't use inverters wouldn't be covered but I was hoping someone had a definitive answer. 685 isn't much help on the subject of interconnection. We already know what we're doing in the way of controlled shutdown.

 

[fmtjfw]

Mostly the rules you need to look at first are the local POCO's rules about interconnect (if they even allow it). If they allow generator interconnect you will have to provide a method of synchronizing your generators to the net. They may require a raft of utility-grade relay protection (probably all would fit in an electronic utility "relay" box). One function would be to disconnect automatically if the net loses power, preventing you from cooking your generator and or killing a lineman. Also a means of disconnect that can be locked and has a visible opening in the circuit (Safety Switch).

Interactive PV inverters have a semiconductor chip that handles all this according to some IEEE or ANSI standard.

 

[ron]

My understanding is that a CHP needs to fall into one of the Point of Connection categories covered in 705.12. It is either connected on the "supply side" OR greater than 100kW and connected on the load side. NOT an integrated electrical system.

Definitely thin considering there is so much delineated for inverters (Article 690 and Section 705.12(D))

No real change for non-inverter interconnection in the 2014 edition.