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SolarEdge•Optimizer

Analysis by Marcus & Team

SolarEdge Optimizer PLC Communication Error

Troubleshoot SolarEdge Optimizer PLC communication errors in residential hybrid inverter systems. Diagnose and resolve issues affecting power production.

Frequently Asked Questions

•How does Power Line Communication (PLC) work in a SolarEdge system?

PLC transmits data over existing DC power lines. The inverter sends and receives signals to and from the optimizers superimposed on the DC voltage. A PLC module in each optimizer encodes and decodes the data.

•What are the NEC requirements for rapid shutdown in residential PV systems?

NEC 2017/2020 requires rapid shutdown of PV systems to de-energize conductors within the array boundary during an emergency. This typically involves a disconnect switch near the array and/or an inverter-integrated rapid shutdown function.

•How can I reduce EMI affecting PLC communication in my SolarEdge system?

Ensure proper grounding and shielding of DC cables. Separate DC cables from AC cables and other potential sources of EMI. Use shielded connectors and avoid running DC cables parallel to long runs of AC wiring.

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Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

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Technical Overview:

SolarEdge optimizers communicate with the inverter via Power Line Communication (PLC). This involves transmitting data over the DC power lines. The inverter uses this data for Maximum Power Point Tracking (MPPT) and performance monitoring. Successful PLC requires a stable DC bus voltage, proper termination, and functional communication circuitry within both the optimizers and the inverter. The optimizers buck the panel voltage and boost current. A breakdown in communication between the optimizer and the inverter leads to lost data, and subsequently loss of MPPT for that panel. In hybrid systems, battery charging and discharging can introduce noise that can interfere with the PLC signal. Communication requires compliant firmware on both the inverter and the optimizers.

Possible Causes:

Defective optimizer(s) with a faulty PLC communication module.
Loose or corroded DC wiring connections between optimizers and the inverter.
Electromagnetic interference (EMI) affecting the PLC signal.
Incompatible or outdated optimizer/inverter firmware versions.
Excessive DC cable length causing signal degradation.
A faulty SolarEdge inverter with a malfunctioning PLC receiver.

Important Warnings:

DC voltages in PV systems can be lethal. Only qualified electricians with proper PPE (personal protective equipment) should work on energized PV systems. Always follow NEC Article 690 guidelines for safe PV system system and maintenance. Ensure the Rapid Shutdown System is functioning correctly before commencing any work on the DC side of the system. Arc flash hazards are present. Always verify the system is de-energized before working on any components.

Step-by-Step Fix:

1

*Safety First:** Disconnect the DC supply to the inverter following NEC 690.15 guidelines. Engage the rapid shutdown system per NEC 2017/2020 requirements. Verify absence of voltage with a calibrated multimeter.
2

*Visual inspection:** Check all DC wiring connections for looseness, corrosion, or damage. Use an appropriately rated torque wrench to ensure proper tightness. Inspect DC connectors for arc tracking or thermal damage.
3

*Firmware Verification:** Using the SolarEdge monitoring portal or SetApp, confirm that both the inverter and optimizers are running the latest compatible firmware versions. Update firmware as needed following manufacturer's instructions.
4

*Optimizer Testing:** Use a SolarEdge testing tool (e.g., a commissioning tool connected via Zigbee) to individually test the communication status of each optimizer. Replace any optimizers that fail to communicate.
5

*Wiring inspection:** Check DC cable runs for excessive length or proximity to sources of EMI. Ensure proper cable shielding and grounding. Consider shortening cable runs if signal degradation is suspected. Refer to SolarEdge system guidelines.
6

*Inverter Diagnostics:** Run the inverter's built-in diagnostic tests to check the PLC receiver functionality. Consult the inverter's service manual for troubleshooting steps related to PLC communication errors.
7

*licensed technician Consultation:** If the issue persists, contact SolarEdge technical support for further assistance. A qualified electrician familiar with SolarEdge systems should perform these steps.

Expert Tip:

Utilize the SolarEdge SetApp commissioning tool to perform a "Site Scan" to identify optimizers with communication issues. The Site Scan feature provides a graphical representation of optimizer communication strength, allowing for quick identification of problematic devices. Consider using a DC clamp meter to check for current on each string before disconnecting it for increased safety and verification of operation.

What to Look For:

The SolarEdge monitoring portal displays a "PLC Communication Error" for one or more optimizers. This results in reduced energy production from affected PV strings. The inverter may report a communication fault or show individual optimizer data as unavailable.

Prevention:

Schedule regular system inspections to check for loose wiring and corrosion.
Keep inverter and optimizer firmware up to date.
Monitor system performance through the SolarEdge portal for early signs of communication issues.
Ensure proper DC cable management to minimize EMI.
Conduct thermal imaging of DC connections annually to identify potential hot spots.