I have designed a large scale PV system (close to 1MW) that has 38 inverters going to 4 different sub combiners. The sub combiners then feed into a final combiner that is fed into a 4160V-480V transformer. There are a lot of long cable runs from the sub combiners. Each sub combiner puts out 450A. See below.

SC-1 (2,385FT - Voltage drop (5.42% using 3 sets of #500 CU THHN))

SC-2 (204FT - Voltage drop (1.42% using #600 CU THHN))

SC-3 (603FT - Voltage drop (2.10% using 2 sets of #500 CU THHN))

SC-4 (978FT - Voltage drop (3.41% using 2 sets of #500 CU THHN))

I know I am violating voltage drop values (2% for feeders) so I plan to take care of that. My question is....does each sub combiner have to have the same voltage drop? Does the bus at the final combiner have to receive the exact same voltage from each sub combiner?

SC-1 (2,385FT - Voltage drop (5.42% using 3 sets of #500 CU THHN))

SC-2 (204FT - Voltage drop (1.42% using #600 CU THHN))

SC-3 (603FT - Voltage drop (2.10% using 2 sets of #500 CU THHN))

SC-4 (978FT - Voltage drop (3.41% using 2 sets of #500 CU THHN))

I know I am violating voltage drop values (2% for feeders) so I plan to take care of that. My question is....does each sub combiner have to have the same voltage drop? Does the bus at the final combiner have to receive the exact same voltage from each sub combiner?

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