Matt Donovan
Member
- Location
- United States
I've heard of "solar-rated" transformers, but I don't see much info out there on this type of transformer. Anyone have experience with these?
- are "solar rated" transformers comparable in cost to other transformers?
- can anyone describe specifically what is meant by "solar rated"? Is there an ANSI or UL spec?
- Anyone have guidance on how to size transformers more intelligently, with or without "solar ratings"? Is specing 65oC rise a solution to allow 100% loading? Are k-rated transformers appropriate?
Many designers will load 1000kW of inverters on a 1000kVA transformer, but inverter manufacturers recommend against this because transformers are not intended for continuous operation at full-load. Solectria, for one, recommends oversizing to at least 105%, others to 110%. I've seen 100% loading cause problems in the field, resulting in over-heating, over-voltage, and systems shutting down.
FYI, my firm designs primarly larger commercial (>500kW) and small utility (<10MW) projects. I'm not talking about residential, but also not talking about massive farms.
- are "solar rated" transformers comparable in cost to other transformers?
- can anyone describe specifically what is meant by "solar rated"? Is there an ANSI or UL spec?
- Anyone have guidance on how to size transformers more intelligently, with or without "solar ratings"? Is specing 65oC rise a solution to allow 100% loading? Are k-rated transformers appropriate?
Many designers will load 1000kW of inverters on a 1000kVA transformer, but inverter manufacturers recommend against this because transformers are not intended for continuous operation at full-load. Solectria, for one, recommends oversizing to at least 105%, others to 110%. I've seen 100% loading cause problems in the field, resulting in over-heating, over-voltage, and systems shutting down.
FYI, my firm designs primarly larger commercial (>500kW) and small utility (<10MW) projects. I'm not talking about residential, but also not talking about massive farms.