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Copyright © Huawei Technologies Co., Ltd. 
 
 
PV modules connected in series in each PV string must be of the same specifications. 
 
The maximum open-circuit voltage of each PV string must be always lower than or equal 
to 1000 V DC. 
 
The maximum short-circuit current of each PV string must be always lower than or equal 
to 23 A. 
 
The positive and negative terminals of PV modules must be connected to the positive and 
negative DC input terminals of the SUN2000 respectively. 
 
 
 
If the SUN2000 is directly connected to the power grid and no three-phase four-wire 
isolation transformer is connected to the output side, ensure that the PV strings are not 
grounded. 
 
If the DC voltage is a stable non-zero value between the positive terminal of a PV string 
and the ground, the PV string has an insulation fault. Rectify the fault before connecting 
cables. 
 
During PV string and SUN2000 installation, the positive or negative terminals of PV 
strings may be grounded if power cables are not properly installed or routed. In this case, 
an AC or DC short circuit may occur and damage the SUN2000. 
 
If the PV strings need to be grounded, install a three-phase four-wire isolation transformer 
on the output side and set the parameter of Isolation to Input Grounded, With TF by 
following the instructions in 7.2.11 Setting Isolation Parameters. If no isolation 
transformer is connected, the SUN2000 will not operate properly. 
Context 
Figure 5-16 shows the MPPT distribution of the SUN2000. 
Figure 5-16 MPPT distribution 
 
 
 
The SUN2000-8KTL to SUN2000-12KTL provide two MPPT routes to track the 
maximum power point for PV strings. Therefore, two to four DC inputs should be evenly 
distributed on two terminal groups. 
 
The SUN2000-15KTL to SUN2000-28KTL provide three MPPT routes to track the 
maximum power point for PV strings. Therefore, two to six DC inputs should be evenly 
distributed on three terminal groups.