SMA SC 400HE Installation - Manual (Page 67)

SMA Solar Technology AG External Connections
Installation Guide SCxxxHE-IEN104432 67
6.2.7 Connecting the AC Cable
The connection must be 3-phase with the following operating voltages:
• U, nominal voltage between the external conductors
– for SC 400HE-11 = 270 V
– for SC 500HE-11 = 270 V
– for SC 630HE-11 = 315 V
• Uo, nominal voltage between external conductor and ground: 1 350 V (depending on the
current operating point of the device)
The connection of one fuse load disconnection unit in the AC cabinet of the inverter to the low-voltage
winding of a medium-voltage transformer is 3-phase.
AC power supply line for IT grid on the copper bars on the outside of the AC cabinet of the Sunny
Central.
Selection of the medium-voltage transformer.
The Sunny Centrals of the HE series are inverters without a low-voltage transformer. Special
transformers are required for connecting the Sunny Central to the medium-voltage grid.
Connecting several Sunny Central inverters in parallel at one transformer coil is not
permitted. If requested, SMA Solar Technology offers support in specifying and selecting
a suitable medium-voltage transformer.
NOTICE!
High voltages in the grid.
Damage to the Sunny Central through faulty AC connection.
Due to the typology of the grid nominal voltages of up to 1 350 V are present between the
external conductor and ground. Pay attention to the dimensioning of the AC cables to be
connected.
• When choosing the AC cables, take into account the increased demands on the
nominal voltage Vo against grounding.
• Dimension the AC cables with a voltage resistance of at least 1 350 V.
• Lay the AC cables ground- and short-circuit proof.
• Only use aluminum cable clips for the cable inlet
of the AC connection.
Connection of aluminum terminal lug
If aluminum terminal lugs are used for connection to the copper bar, refer to notes in
chapter 6.1 ”Connecting High-Current Contacts” (page 50).