PV inverter and panel schedule

[J-InTheJ-Box]

Hello fellow forum readers and participants!
Got one that I haven't been able to get any good hits using Dr. Google. How do you add 60KW inverters to your panel schedules? When you're adding PV inverters to a new (or existing) electrical system and its time to update the panel schedule, what is the process or code references that need to be looked at? Before anybody says it, I've already sized my bus bars according to the code. How does it impact your connected load, the demand load, and the rest of the reporting going back to the source?

My building is a new admin building with ~500KW of solar being added. All the solar is being connected to the distribution system.

 

[jaggedben]

It doesn't affect your load whatsoever, but have you looked at Article 705?

It's a little unclear what exactly you're asking, and what you've already done.

 

[J-InTheJ-Box]

Thanks for the feedback. I have sized my equipment per art 705 and followed busbar methods a-e.

I'm attempting to build my panel schedule for the board that these PV inverters are being connected to. I'm just a little lost in the sauce since the inverters are injecting current into my distribution system instead of pulling a load. So, what do I put into the load column? Is the 60 KW each inverter generates considered the load? Do I not not add any contribution from the inverters to the demand load? For a pure PV board, would the total column just say Connected kVA: 0, Demand Load kVA: 0?

 

[jaggedben]

The PV is not considered a load. It also has no affect on 'demand load'. That is, while you may in practice see reduced demand due to the PV, it's not something that can be counted upon such that it affects any other design considerations. Think of a rainy day.

Since I'm just in the business of installing solar and not in the business of doing commercial panel schedules, I'm sorry I can't offer a 'this is the way I do it' answer. But my suggestion might be to add a new column: 'Connected Source'. Or perhaps more than one new column. If you wanted to lay it out fully for someone who might not otherwise understand, you might have:
Total connected kVA: (load + PV)
Connected Load kVA: (what I believe you're currently calling Connected KVA, i.e. load without PV)
Connected Source kVA: (PV)
Demand kVA: (The greater of (a) your demand load calc or (b) 125% of inverter KVA. Notice I don't call it 'load' anymore, because the max demand on the circuit might be for outputting PV instead, depending on circumstances.)

Or perhaps that's needlessly complicated, and you just need to append notes for each panel that state the connected PV, the 705 calculation and section being invoked, and whether the minimum busbar and feeder requirement is the load or the source. For your PV only panel, then, you'd have the load section essentially blank.

Make sense?

 

[J-InTheJ-Box]

The PV is not considered a load. It also has no affect on 'demand load'. That is, while you may in practice see reduced demand due to the PV, it's not something that can be counted upon such that it affects any other design considerations. Think of a rainy day.

Since I'm just in the business of installing solar and not in the business of doing commercial panel schedules, I'm sorry I can't offer a 'this is the way I do it' answer. But my suggestion might be to add a new column: 'Connected Source'. Or perhaps more than one new column. If you wanted to lay it out fully for someone who might not otherwise understand, you might have:
Total connected kVA: (load + PV)
Connected Load kVA: (what I believe you're currently calling Connected KVA, i.e. load without PV)
Connected Source kVA: (PV)
Demand kVA: (The greater of (a) your demand load calc or (b) 125% of inverter KVA. Notice I don't call it 'load' anymore, because the max demand on the circuit might be for outputting PV instead, depending on circumstances.)

Or perhaps that's needlessly complicated, and you just need to append notes for each panel that state the connected PV, the 705 calculation and section being invoked, and whether the minimum busbar and feeder requirement is the load or the source. For your PV only panel, then, you'd have the load section essentially blank.

Make sense?

That makes sense. I'll have to include a field into my schedules that allows for passing the PV source information up the chain to the service transformer. I'm doing this in Revit, so now i get to tinker.

Thanks for the help jaggedben.

 

[gadfly56]

That makes sense. I'll have to include a field into my schedules that allows for passing the PV source information up the chain to the service transformer. I'm doing this in Revit, so now i get to tinker.

Thanks for the help jaggedben.

If you ask nicely I'm sure someone will shoot you and put you out of your misery.

 

[J-InTheJ-Box]

If you ask nicely I'm sure someone will shoot you and put you out of your misery.

It is unfortunate, yes. I was dragged, kicking and screaming, away from using AutoCAD. The arch-engineering world is embracing revit with wide open arms. It is odd to use on its surface, especially if you've grown up with AutoCAD, but once you get down into the data layer, its almost like programming. The guy I sit across from is applying the finishing touches towards linking the single line diagram to the panels and electrical gear in the rest of the model.