Xantrex XW4024-120 Operation Manual page 73

Problem
In a grid-interactive
mode, the unit is
experiencing excessive
anti-islanding faults. The
utility grid is not
dropping out, yet the
unit is disconnecting
from the grid.
975-0240-01-01
Possible cause
The unit has two sets of AC limits:
adjustable AC qualification limits (as set
on the AC Settings menu), and non-
adjustable anti-islanding limits which
are required to have a 5-minute
reconnect delay before returning to grid-
interactive mode (Sell Mode or Grid
Support).
While in Sell Mode and in Grid Support,
these two sets of limits are both active.
Whichever limits are set to more
restrictive values (the narrower voltage
and frequency windows) will trip first
when the utility grid varies from normal
values.
If the AC qualification limits are set
outside the fast anti-islanding limits (see
F27, F30, F37 and F40), the unit will
experience less frequent disconnects
from the utility, but when it does
disconnect there will be a 5-minute
delay (minimum) before re-entering a
grid-interactive mode. During this 5-
minute delay, all other modes of
operation will be available, assuming the
grid re-enters the user-set frequency and
voltage limits (see "AC Settings" on
page 3–16).
If the AC qualification limits are set
inside the anti-islanding limits, then the
unit will experience more frequent
disconnects from the utility, but when it
does disconnect there will not be a 5
minute delay before entering a grid-
interactive mode, assuming the grid re-
enters the user-set frequency and voltage
qualification limits.
The impedance of the utility grid is too
high for the power being sold to the grid.
The utility grid impedance may be on
the high end if the installation is too far
from the utility sub station.
Inverter Troubleshooting
Solution
Adjust the AC1 voltage and frequency
settings (see "AC Settings" on page 3–16).
Raise the high voltage and frequency
settings, and lower the low voltage and
frequency settings.
Reduce the Max sell current until unit
disconnecting.
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