Huawei SUN2000 Series User Manual page 35

SUN2000 Smart PV Optimizer
User Manual
Figure 4-7 Measuring the PV string resistance
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Step 3 Connect cables between the PV string and the inverter.
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2.
Issue 04 (2023-04-21)
The measured PV string resistance must meet the following requirement: The
PV string resistance (R1 + R2)/2 kΩ ≈ N x 1 kΩ. For example, if there are 16
optimizers in a PV string, the PV string resistance should be about 16 kΩ.
NO TE
Explanation:
– The PV string resistance is (R1 + R2)/2 kΩ. In the preceding figure, R1 and R2 are
the PV string resistance values measured when the multimeter is connected
correctly and reversely, respectively.
– When optimizers are connected to PV modules, the output resistance of each
optimizer is 1±0.1 kΩ. Therefore, the resistance of a PV string is approximately
equal to 1 kΩ times the number of optimizers.
If the measured PV string resistance is abnormal, rectify the fault by referring
to 6.1 How Do I Troubleshoot the Problem that the PV String Resistance
Is Not Equal to the Number of
Determine the positive and negative terminals of the PV string cables and
prepare correct cable labels.
Figure 4-8 Determining the positive and negative terminals of PV string
cables
Connect the PV string cables to the inverter.
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4 Installation and Commissioning
Optimizers?.
29