SolarEdge SE100K-US Voltage

R

ruxton.stanislaw

Senior Member
Location
Arkansas
Occupation
Laboratory Engineer
Is the nominal voltage field programmable on the SolarEdge SE100K-US? We are looking for a similar set of inverters, with a target voltage of ~ 440Y/254V.
 
BackCountry

BackCountry

Electrician
Location
Southern California
Occupation
Licensed Electrician and General Contractor
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
ruxton.stanislaw said:
Is the nominal voltage field programmable on the SolarEdge SE100K-US? We are looking for a similar set of inverters, with a target voltage of ~ 440Y/254V.
Click to expand...
Inverter AC voltage is not programmable; the inverter synchs to the line voltage as long as it is within its voltage range. That range is expandable on some inverters, but in any case 440V will be very close to the lower bound if it is in the range at all, so even if it is it won't take much of a dip in line voltage to shut the inverter(s) down. Have you considered using a buck-boost transformer to boost the line voltage to 480V?
 
C

Carultch

Senior Member
Location
Massachusetts
ggunn said:
Inverter AC voltage is not programmable; the inverter synchs to the line voltage as long as it is within its voltage range. That range is expandable on some inverters, but in any case 440V will be very close to the lower bound if it is in the range at all, so even if it is it won't take much of a dip in line voltage to shut the inverter(s) down. Have you considered using a buck-boost transformer to boost the line voltage to 480V?
Click to expand...
On some models of inverters, you can program the AC voltage range to non-US standard settings and allow it to operate on foreign grids. You will inevitably take a hit to your maximum power, since maximum current can't be changed. This means a 100 kW inverter built for a 277/480V grid, would effectively act as an 91 kW inverter on a 254/440V grid.

It's common when inverter manufacturers build similar inverters for both North America and the rest-of-world, that the foreign counterparts of the inverter exist with a lower power proportional to the grid voltage. E.g. a 30 kW US model, would be equivalent to a 25 kW rest-of-world model. Likely, the manufacturer uses the same core circuitry, and just a factory firmware setting for grid compatibility. This would mean that it should be possible in theory to do this, and it's just a matter of finding information not normally documented to the customer, to determine if you can do this.

The DC interface on foreign counterparts is often different, so can mean extra equipment to comply with NEC standards using rest-of-world models, when NEC issues are often solved as integrated features within the inverter.
 
BackCountry

BackCountry

Electrician
Location
Southern California
Occupation
Licensed Electrician and General Contractor
ggunn said:
Inverter AC voltage is not programmable; the inverter synchs to the line voltage as long as it is within its voltage range. That range is expandable on some inverters, but in any case 440V will be very close to the lower bound if it is in the range at all, so even if it is it won't take much of a dip in line voltage to shut the inverter(s) down. Have you considered using a buck-boost transformer to boost the line voltage to 480V?
Click to expand...

It’s not uncommon where I’m at to see a secondary voltage at the service disconnect with zero load at 460v on a 3ph 480/277v service.

We have installed PV without issue on those services — sometimes we need a special grid profile made by the inverter manufacturer, but overall I’ve yet to need to use a transformer or buck booster to improve the situation.

See our utility grid minimum voltages here: https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_RULES_2.pdf

The bigger concern you see here is usually voltage rise depending on the conductor sizing and length from the inverter to the point of interconnection. For example, I’ve had services on single phase at 250v where the inverters were 200’ away. We had to upsize for nearly zero loss to meet the max inverter voltage spec.
 
R

ruxton.stanislaw

Senior Member
Location
Arkansas
Occupation
Laboratory Engineer
Thanks guys. This is for off-grid use in a rural area, sorry I did not make that clear. There will be an ATS after the inverter system, for a generator.

Carultch said:
This means a 100 kW inverter built for a 277/480V grid, would effectively act as an 91 kW inverter on a 254/440V grid.
Click to expand...
The current being the limiting factor makes sense; we are OK with that compromise. This is mostly for 240 and 400 V single phase (VFDs or hot water tanks) rated equipment. With the voltage tolerance range of the equipment and voltage drop in mind, I arrived at the 254 V target, choosing the upper end of the range for efficiency.
 
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
ruxton.stanislaw said:
Thanks guys. This is for off-grid use in a rural area, sorry I did not make that clear. There will be an ATS after the inverter system, for a generator.
Click to expand...
Off grid is a different ball of wax. What are you using for storage? How are you furnishing line voltage to the inverters?
 
R

ruxton.stanislaw

Senior Member
Location
Arkansas
Occupation
Laboratory Engineer
ggunn said:
Off grid is a different ball of wax. What are you using for storage? How are you furnishing line voltage to the inverters?
Click to expand...
I need an inverter that can operate islanded and lead the system with its own frequency.

The storage concept is getting down a rabbit hole; rather than galvanic storage, we are are engineering a system to store a near freezing water-glycol solution to cool the building at night time when there are no other required loads. A bank of super capacitors may be incorporated on the DC side to handle surges/"start up" current or we will put soft starters on the non-VFD compressors for this system.
 
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
ggunn said:
I have designed many commercial PV systems with SolarEdge inverters and they are all doing just fine.
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And I have installed many residential Solaredge inverters and they have not all done just fine. But I said that mainly because this is an off-grid application. Sol-Ark is built around off-grid as a company in a way that SE is completely not.
 
R

ruxton.stanislaw

Senior Member
Location
Arkansas
Occupation
Laboratory Engineer
As stupid or archaic as it might sound at first, I am starting to think a DC motor -> alternator might be more reliable than all of this inverter technology. I am in the part of the world where you essentially have have to buy two of everything or take a flight and bring the replacement in your suitecase. (For example, a small PCI-e bridge for my computer took six months to get here and ended up costing $800 in taxes and fees...) What do you guys think about that solution, or am I out to lunch?
 
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