CPS SCA50KTL-DO/US-480 - AC and Ground Connection Procedures

52
3.3.4. AC and Ground Connection
The following section describes the AC and ground connections.
3.3.4.1. Acceptable Transformer Configurations
The SCA50/60KTL inverters operate at 480V
AC
/Wye output. If another
voltage/configuration is required a transformer may be necessary.
Wye (Inverter) / DELTA (Utility)
Wye (Inverter) / WYE (Utility)
TRANSFORMER
INVERTER
L1
L2
L3
N
PE
A
C
B
PE
N
UTILITY
PER CODE
OPTIONAL PER CPS
TRANSFORMER
INVERTER
L1
L2
L3
N
PE
A
C
B
PE
N
UTILITY
PER CODE
PER UTILITY REQUIREMENTS
OPTIONAL PER CPS
Fig 3-31 AC Acceptable Transformer Winding Configurations
NOTES:
1. The nearest upstream transformer must be a grounded WYE on the
inverter side. The Neutral on the Utility Side (H0) and Inverter Side (X0)
may be connected internally and brought out as one terminal in the LV
compartment and labeled (H0X0).
2. Transformer short-circuit impedance (Z%) should be less than 6%.
3. The transformer VA rating must be at least 100% of the sum of the
connected inverter VA ratings.
4. CPS recommends the transformer VA rating be selected based on IEEE
C57.159-2016 Guide on Transformers for application in Distributed
Photovoltaic (DPV) Power Generation Systems. It is the responsibility of
the system designer to determine and take in account the reliability of the
transformer or other system parameters.
5. The transformer does not require a static shield.
6. The maximum number of inverters connected to a single transformer is 70.
7. The recommended maximum voltage-drop on the Inverter to Point of
Common Coupling (to the grid) is 2% at full load – including conductor
temperature considerations. Voltage drop greater than 2% may require
changing the transformer tap or as a last resort adjusting the GridMaxVolt
trip point settings.