electro7
Senior Member
- Location
- Northern CA, US
- Occupation
- Electrician, Solar and Electrical Contractor
Looking to do a quick design for bidding purposes on design build utility scale sites. These sites average around 3.4MW.
250kw CPS string inverters are shown. I see by the spec sheet they only have 36 inputs- 12 mppts with 3 inputs each. Each mppt max current is 26A.
530W First Solar series 7 modules with a high Voc (226V) which allows for only 6 modules max per string. Isc is 3.05A.
I don't see how this configuration will work with a 1.3 ratio. A 1.3 ratio would be around 613 modules per inverter. 613/6 modules per string = 102.16 strings per inverter. 103 (102.16 rounded up)/12 mppt inputs = 8.58 strings per input.
Isc 3.05 x 9 (8.58 strings rounded up)= 27.45A per MPPT.
Any thoughts on this math and how it could work?
Also, when the MPPT says 26A max does that include the 1.25 continuous load multiplier? I'd assume it would which in this case would only allow for 6 strings per MPPT. 6 x 3.05A x 1.25 = 22.88A. 7 strings takes it over 26A.
Appreciate the help. I think I must be missing something.
250kw CPS string inverters are shown. I see by the spec sheet they only have 36 inputs- 12 mppts with 3 inputs each. Each mppt max current is 26A.
530W First Solar series 7 modules with a high Voc (226V) which allows for only 6 modules max per string. Isc is 3.05A.
I don't see how this configuration will work with a 1.3 ratio. A 1.3 ratio would be around 613 modules per inverter. 613/6 modules per string = 102.16 strings per inverter. 103 (102.16 rounded up)/12 mppt inputs = 8.58 strings per input.
Isc 3.05 x 9 (8.58 strings rounded up)= 27.45A per MPPT.
Any thoughts on this math and how it could work?
Also, when the MPPT says 26A max does that include the 1.25 continuous load multiplier? I'd assume it would which in this case would only allow for 6 strings per MPPT. 6 x 3.05A x 1.25 = 22.88A. 7 strings takes it over 26A.
Appreciate the help. I think I must be missing something.