Xantrex Technology PV225S-480-P - Manual (Page 39)

Utility Side Isolation Transformer Requirements
152606 2–5
Utility Side Isolation Transformer Requirements
The PV225S is supplied with a a high-efficiency custom Wye:Wye isolation
transformer as part of the AC Interface/Transformer assembly. The utility side
windings of the isolation transformer are configured Wye and must match the
voltage at the utility inter-tie. The PV225S is a balanced, three-phase, current-
sourcing inverter and only operates with the presence of a stable utility voltage.
The transformer is also supplied with a neutral connection on the utility
interconnect. Connection of this utility-side neutral does not affect the operation
of the inverter, however connection of the neutral on the inverter-side does affect
the operation and must be left floating or disconnected. Single-phase, grounded
loads which may be present between the transformer and utility, will maintain
their existing ground reference at the utility distribution transformer.
Electrical Diagrams and Schematics
Since installations vary widely, a sample electrical diagram of the PV225S is
provided in Figure A-1 on page A–3. This diagram is to be used for system
planning purposes only.
For more detailed information, refer to the schematic illustrations.
• Figure A-2, “PV225S Schematic for Main Power Distribution (152812 A1)”
on page A–4
• Figure A-3, “PV225S Schematic for Control Power Distribution
(152812 A2)” on page A–5
• Figure A-4, “PV225S Schematic for Converter Control Unit (152812 A3)” on
page A–6
CAUTION: Equipment Damage
If the Isolation Transformer (T6-X0) neutral terminal is tied to ground, it will cause
irreparable damage to the PV225S. Check local regulations for their requirements
regarding the connection of these neutrals.
WARNING: Lethal Voltage
Grounding the neutral of a Wye-wound transformer may create an “open delta” condition,
depending on the utility configuration. This condition may keep the PV225S from
detecting a loss of phase condition on the utility system, which may allow potentially
lethal voltage to be present on the open-phase wiring.