Sungrow SG36CX-US, User Manual

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34
5.5 AC Cable Connection
5.5.1 AC Side Requirements
Before connecting the inverter to the grid, ensure the grid voltage and frequency
comply with requirements, for which, refer to
"
10.1 Technical Data
"
. Otherwise, contact
the electric power company for help.
Connect the inverter to the grid only after getting an approval from the local
electric power company.
M Mu ullttiip plle e IIn nvve errtte errss iin n p pa arra alllle ell C Co on nn ne ec cttiio on n
If multiple inverters are connected in parallel to the grid, ensure that the total number of
parallel inverters does not exceed 30. Otherwise, please contact SUNGROW for
technical approval.
M MV V T Trra an nssffo orrm me err
The MV transformer used together with the inverter should meet the following
requirements:
•
The transformer may be a distribution transformer, and it must be designed for the
typical cyclical loads of a PV system (load in the day and no load at night).
•
The transformer may be of the liquid-immersed type or dry type, and shield winding
is not necessary.
•
The line-to-line voltage on the LV side of the transformer should endure the output
voltage of inverter. When the transformer is connected to to the IT grid, to-ground
withstanding voltage of the LV winding of the transformer, the AC cables, and the
secondary equipment (including the relay protection device, detection & measuring
device, and other related auxiliary devices) should not be lower than 1,100V.
•
The line-to-line voltage on the MV side of transformer should comply with local
power grid voltage.
•
A transformer with a tap changer on the MV side is recommended in order to keep
consistent with the grid voltage.
•
Transformer with a short-circuit impedance of 6% (permissible tolerance: ±10%) is
recommended.
•
The voltage drop of system cable is no more than 3%.
•
The DC component that the transformer can withstand is 1% of the fundamental
current at rated power.
•
For thermal rating, the load curve of the transformer and environment conditions
should be taken into account.
•
The apparent power of the inverter should never exceed the power of the
transformer. The maximum AC current of all inverters connected in parallel must be
taken into account. If more than 30 inverters are connected to the grid, contact
SUNGROW.
5 Electrical Connection User Manual