Monitoring Batteryless PV Systems: Page 4 of 5

Intermediate

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A monitoring system can help assess PV system performance in real time or over a duration of time, and provide on-site and remotely accessible information for system owners and installers, and the general public.
Batteryless PV monitoring systems provide Web portals for remote, online access to the system through a computer, smartphone, or tablet.
The Fronius Datamanager is a wireless data logger that comes preinstalled in new inverters, and can be retrofitted to older models.
Solectria’s SolrenView DAS Gateway can monitor up to 16 inverters and owners can opt to share data publicly.
While net-energy meters and PV production meters both look like the ubiquitous kWh meter, it’s their position in the system that defines what they are monitoring: A net meter is placed between the AC service entrance and the utility grid connection.
While net-energy meters and PV production meters both look like the ubiquitous kWh meter, it’s their position in the system that defines what they are monitoring: A PV production meter is positioned between the inverter and the AC service entrance connection.
PV system data can be displayed via a wireless tabletop unit, like the SMA America Sunny Beam.
A current transducer snaps closed around a wire to measure current via induction.
Data can be conveyed from the data logger to the display or network connection via dedicated cable, wirelessly (as shown), or over power lines.
Most monitoring systems display very similar data, albeit in different visual interfaces. The biggest difference is that MLPE systems, like this Enphase Enlighten display, allow monitoring of individual PV modules.
Schneider Electric’s Conext Monitor 20 can monitor data from up to three Conext RL inverters.
PV monitoring options offered by inverter manufacturers, such as Solectria’s SolrenView (above), offer similar features and customizable views.
The Enphase Envoy collects data via the power lines from Enphase microinverters; besides an AC power supply, no additional wiring is necessary.
The SolarEdge mobile app allows monitoring system performance from almost anywhere. Most portals also provide email alerts.
ABB’s Aurora Vision Web portal displays data from each microinverter. The eight inverters in this system appear as overlapping lines on the graph—each inverter’s production has been nearly identical for the week shown, indicating that the system is performing well.

MLPE Systems

Systems with MLPEs capture module-level data via the module-mounted inverter or electronics, and transfer that data either wirelessly or using PLC. This level of data capture supplies deep details on the PV system’s functioning. An individual PV module’s power output (including DC or AC current and voltage) can be viewed as it changes throughout the day, and cumulative energy for a day, week, month, or year can be viewed and reported for each module or the whole system.

The method of data transfer varies by manufacturer. For example, Enphase, SMA America, and SolarEdge’s microinverter systems all gather data via PLC from the module-mounted electronics, while ABB/Power-One microinverters transmit data wirelessly to a gateway device.

The Enphase Envoy gateway collects microinverter performance data using PLC. A cable transmits data to the router, or an adapter that comes with the Envoy unit can enable a wireless option. The Envoy unit—which requires an AC power source—transmits data to the free Enlighten Web portal. Enphase recommends installing a dedicated circuit for the Envoy power supply outlet so that RF interference doesn’t disrupt data communication with the microinverters.

SolarEdge data is collected from MLPEs by the inverter (there is no separate gateway device to install as it is integrated into the inverter). The data is transmitted via cable or wireless to the router, and sent on to the free SolarEdge PV Monitoring Portal. Their portal can also be accessed from smartphones or tablets.

SMA America’s Sunny Boy 240-US microinverters require one SMA Multigate-US device for every 12 microinverters. The Multigate-US gathers inverter data via PLC, and is installed prior to the point of interconnection (for example, prior to the back-fed AC breaker), and feeds the microinverters’ AC output power collectively into the grid. It filters radio frequency from the power line to avoid data interference. The Multigate is hardwired (no built-in WiFi), but a wireless bridge could be installed to avoid a long cable run. PV system data is transmitted from the site router to the free Sunny Portal. There is a smartphone and tablet app available as well.

Up to 30 ABB (Power-One) MICRO inverters can be wirelessly monitored by one CDD gateway device, which requires an AC power source. The CDD gateway is required for commissioning the microinverters, and it wirelessly transmits data via a site router to the ABB Aurora Vision Web portal, provided free of charge and available on mobile devices as well. For both SMA America and ABB microinverters, the gateway device is a required system component and enables system monitoring, thus any installed system comes complete with a data monitoring package.

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