Design Considerations For Sites With Power Export Limit Requirements - enphase IQ8 Design Manual

Therefore, it is critical to maintain good communication between devices with minimal interference on
the PLC signal. Enphase recommends the following design considerations for maintaining reliable PLC
communication between microinverters and IQ Gateway Commercial 2.
Designs for reliable PLC require the following:
•
Do not exceed 275 IQ8 Commercial Microinverters per gateway.
•
Install the gateway as close as possible to the microinverters. Consult Enphase if you need to
exceed 75 meters (246 feet) conductor length between the gateway and the last IQ8
Commercial Microinverter in the circuit.
•
Install a line communication filter to isolate gateway communications domains. Filtering is
mandatory when multiple gateways are installed to separate communication domains.
•
For sites with multiple gateways, the conductors and conduits of each gateway
communication domain must be kept physically separated from the conductors and wiring of
other communications domains by at least 12 inches using properly grounded metal conduits.
Coupling of the signals can occur between the conductors and conduits when run together,
especially on long conduit and wire runs.

2.4.3 Design considerations for sites with power export limit requirements

The Enphase power export limit (PEL) function can be configured to operate at different power export
limits to meet the site requirements, as is required by the local utility service. The value for the power
export limit is defined within a specific Enphase grid profile. The installer needs to use different grid
profiles for different PEL values.
Primary Protection
An Enphase IQ8 Commercial system can support the Power Export limit by using a PEL Grid profile and
an IQ Gateway Commercial 2 with Production CTs installed at solar PV subpanels and Consumption CTs
installed at/near the utility service location. When configured for the Power Export limit, the Enphase
system still automatically limits the PV generation so that energy exported to the grid is zero or the
power export limit set within the grid profile. This functionality is set through the grid profile and called
Soft Export Limit.
Secondary protection
The IQ Gateway Commercial 2 also has a secondary level of protection called a hard PEL. The hard PEL
operates a voltage-free contact in the gateway that can be wired to an external contactor to physically
disconnect the IQ8 Commercial Microinverters from the grid if the power export limit target is not
reached in the configurable time frame. Refer to Figure 16 to check for relay contacts on the IQ Gateway
Commercial 2.
Export limiting for an IQ Gateway Commercial 2 requires the following system components:
•
IQ8 Commercial Series Microinverters (Maximum 275 microinverters per IQ Gateway
Commercial 2).
•
The site must have only a single IQ Gateway Commercial 2 installed to be PEL capable. Sites
with multiple gateways cannot perform Power Export Limit collectively.
•
Production current transformer (400 A) and Consumption current transformers (600 A) are
fitted and enabled via the Installer Enphase Installer App.
•
Adequate power line communication between gateway and microinverters—showing three
bars or more in the Installer Enphase Installer App for all installed microinverters. The
installer should also troubleshoot and identify if power line communication is degraded or
disrupted by noise using the FFT analysis in the Enphase Installer App.
•
A grid profile for the site, which includes the Power Export Limit value set to the export
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IQ8 Commercial Microinverter grid-tied PV system
November 2023
USG-00026-1.0