Sungrow SG36KTL-M, User Manual

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User Manual 6 Electrical Connection
37
MPPT
2
MPPT
1
Inverter Inside
MPPT
3
PV Input 2
PV Input 1
PV Input 3
To make sure maximum DC power can be utilized, PV strings connected to
individual input MPPT should have a homogenous structure, including the
same type, the same number, identical tilt and identical orientation.
Prior to connecting the inverter to PV inputs, the following electrical specifications
must be met simultaneously:
Total DC Power Limit
Open-circuit Voltage
Limit for Each Input Short-circuit Current
Limit for Each Input
36.8KW 1100V 36A
Considering the negative voltage temperature coefficient of PV module, more
attention should be paid to the open-circuit voltage of PV strings when designing at
the lowest ambient temperature.
TakeYL250P-29bPV cells for example.
Item Parameter
PV cell type YL250P-29b
Power 250W
Open-circuit voltage (STC) 37.6V
Short-circuit current (STC) 8.92A
Open-circuit voltage temperature coefficient (
β
) -0.32%/°C
No. of PV cells in a PV string 22
Under the STC condition, where ambient temperature is 25°C, the open-circuit
voltage of PV cells is 37.6V
×
22=827.2V<1100V.
Supposed that the lowest temperature is -25°C, the open-circuit voltage of PV cells is
22×37.6V×[1+β×(min. ambient temperature- STC temperature)] =
22×37.6V×[1+(-0.32%/°C) ×(-25°C-25°C)]=952.4V<1100V (meet the operation
requirement).
Therefore, PV string should be designed to meet the open-circuit voltage
requirement even under the lowest ambient temperature condition.