Pdexter1210
New User
- Location
- Texas
- Occupation
- Engineer
Hello, new to the forum, thanks in advance for your responses/advice. I'm currently scoping a new construction project which will incorporate PV solar, battery storage, a backup diesel generator and some 3 phase CNC and welding loads (~200a 3p connected but not continuous for the shop), in addition to some sub-panel fed residential single phase service (200a 1p). The POCO has set a 75kva padmount to deliver 480/277v 3phase metered service and they are allowing me to install up to 48kW of PV solar and they do support net metering of the PV, so sellback is an option. I am trying to determine best course of action for installing the PV inverter, generator, and whether to backup all expected loads (total 3phase backup) or just critical single phase load for the residence.
Q1 - Since I'm receiving 480/277v from the utility, it seems to me that it's most efficient for the PV and generator to also be 480/277v systems. Costs will be a concern, but I will also lean on the secondary market for the generator and step-up/down transformers as much as I can to keep things reasonable. All other things being equal, would you try to keep everything at the 480/277v level?
Q2 - I am admittedly new to the PV world, so apologies in advance for 101 level questions. I would prefer to use PV to power/backup the entire system, so I have been educating myself on 3ph PV inverters. Most of the residential scale inverter systems require 3 inverters to create 3ph service and then can only provide 208v, which has led me investigate commercial inverters which can support 3ph 208v or 480v with a single inverter. I have found a 3ph 480v inverter which allows 200a pass through and supports the generator and PV sizing in my scope, so that seems very appealing. The pricing for a single 3ph commercial inverter is significantly less than buying 3 resi inverters to create 3ph 208V, so that is also appealing. Any obvious things that I may be overlooking as I think through whether to go 1ph or 3ph with the inverter?
Q3 - In general I'm starting with a blank sheet of paper and it just seems to me that sizing everything to 3ph 480/277v will be so much simpler in the long run (even with the added dry step-downs here and there) that I should lean this direction. Any general thoughts here would be appreciated as well.
Again, thanks in advance.
Q1 - Since I'm receiving 480/277v from the utility, it seems to me that it's most efficient for the PV and generator to also be 480/277v systems. Costs will be a concern, but I will also lean on the secondary market for the generator and step-up/down transformers as much as I can to keep things reasonable. All other things being equal, would you try to keep everything at the 480/277v level?
Q2 - I am admittedly new to the PV world, so apologies in advance for 101 level questions. I would prefer to use PV to power/backup the entire system, so I have been educating myself on 3ph PV inverters. Most of the residential scale inverter systems require 3 inverters to create 3ph service and then can only provide 208v, which has led me investigate commercial inverters which can support 3ph 208v or 480v with a single inverter. I have found a 3ph 480v inverter which allows 200a pass through and supports the generator and PV sizing in my scope, so that seems very appealing. The pricing for a single 3ph commercial inverter is significantly less than buying 3 resi inverters to create 3ph 208V, so that is also appealing. Any obvious things that I may be overlooking as I think through whether to go 1ph or 3ph with the inverter?
Q3 - In general I'm starting with a blank sheet of paper and it just seems to me that sizing everything to 3ph 480/277v will be so much simpler in the long run (even with the added dry step-downs here and there) that I should lean this direction. Any general thoughts here would be appreciated as well.
Again, thanks in advance.