Conext XW PRO 6848 6,800W 48V Installation

AC Coupling
Off-grid AC Coupled system architecture is often used to create a stand-alone grid.
Commonly this means that PV inverters are connected to the output of a battery-based
inverter/charger putting both on the same AC bus along with the AC loads. In this
scenario, the battery powered inverter charger provides the necessary frequency and
voltage to enable the PV inverter to produce power. This type of system must be able to
maintain power generation in balance with power consumption at all times. If there is
more power being generated than can be consumed by the loads, power will flow to the
inverter/charger and be converted to DC power which flows into the battery. Once the
battery reaches capacity, power generation by the PV inverter must be curtailed to
maintain the balance between generation and consumption. As the battery bank reaches
capacity, Conext XW Pro curtails PV inverter generation by raising the AC line frequency
causing compatible PV inverters to reduce their power output in an orderly manner. This
is called Active Frequency Shift Power Curtailment. In some compliance regions, when
the grid returns from an outage, Conext XW Pro will cause any AC coupled PV inverter to
transition offline via the same mechanism prior to grid reconnection.
During a grid outage even a home with a grid-tie PV inverter system will be without power
because PV inverters cannot produce power without the presence of a reference voltage
and frequency. To enable the PV inverter to provide power during a grid outage the
Conext XW Pro is retrofitted in front of the PV inverter. The PV inverter is rewired from
the grid connection to a critical load (sub) panel and is AC Coupled to the Conext XW Pro
AC Output port. When the grid is present, PV inverter power feeds the loads and any
excess is exported by Conext XW Pro to the grid using AC1 (where permitted by the
local utility). During a grid outage, Conext XW Pro anti-islanding protection helps to
prevents power from being exported to grid on AC1. Conext XW Pro then uses Active
Frequency Shift Power Curtailment to reduce the power output of compatible PV
inverters, maintaining the balance of generation and consumption.
Consult the manufacturer's specifications to determine if your PV inverter is compatible
with Active Frequency Shift Power Curtailment. Conext XW Pro AC coupling function is
enabled by default (Advanced Features Menu).
NOTICE
AC COUPLED PV INVERTER COMPATIBILITY
AC power generated by AC coupling PV inverters with Conext XW Pro must be consumed
by AC loads or used to charge batteries. As an alternative, the excess power produced from
a PV inverter can be routed to dump loads. Do not AC couple PV inverters with the Conext
XW Pro that are unable to reduce, derate or cease the excess PV inverter power in
response to the changes in AC line frequency controlled by the Conext XW Pro. Consult the
manufacturer's specifications of your PV inverter and confirm compatibility.
Failure to follow these instructions can result in equipment damage.
The AC coupling advanced setting should remain enabled except in cases when the DC
voltage level is allowed to have large variations and the line frequency needs to remain
constant.
Conext XW Pro Owner's Guide Introduction
28 This document is intended for use by qualified personnel 990-91227A-01