Solar Lattice

FailureMode

Power line communication interference

ID
fm:powerline-communication-interference
IRI
https://solarlattice.org/kb/fm/powerline-communication-interference
Status
active
Also known as
PLC communication impaired, AC cables laid in parallel, communication error rate, Communication impaired, Communication disrupted

Power line communication interference happens when the data signal between devices is disturbed by electromagnetic fields from nearby energized AC cables. In the field it usually shows up as an impaired or disrupted communication alarm, with no valid signal on the network line. On microinverter systems that use power line communication, a gateway that cannot detect the microinverters should be treated as a PLC problem. Check how the cables are laid: network cables need plenty of clearance from AC cables. For PLC links, keep low-voltage AC cables apart from medium-voltage AC cables when they run in parallel, and cross them at close to a right angle. Only put AC cables fed from the same box-type transformer in a shared trench, and keep cable trays from different transformers apart. Grounding the communication device properly and routing its cables correctly reduces interference and improves communication quality.

<!-- review notes

Claims

caused_by

c1 drafted · lead Signal cable electromagnetic interference

AC cables in operation create an electromagnetic field that can induce leading or lagging interference in network cables while data is being sent.

affects

c2 drafted · lead Network cable

c3 drafted · lead AC cable

For PLC, the AC cables both carry the signal and can be the source of interference, so how they are laid matters.

review note: support check: partial - AC cable routing is covered, but the claim that AC cables carry the PLC signal is not stated in the passages.

c4 drafted · lead Microinverter

The microinverters communicate over power line communication, so detection problems are handled as PLC troubleshooting.

review note: support check: partial - Microinverters use PLC and detection issues are PLC troubleshooting, but the link to interference affecting microinverters is only implied.

presents_as

c5 drafted · lead Communication loss

Reported as communication impaired or disrupted, with no valid signal on the network line.

review note: support check: partial - Communication impaired/disrupted with no valid signal is stated, but not as a symptom of PLC interference specifically.

c6 drafted · lead MLPE detection failure proposed

The gateway fails to detect microinverters, and this is troubleshot as a power line communication issue.

review note: support check: partial - Detection issues are troubleshot as PLC issues, but the passage does not say the gateway fails to detect microinverters due to interference.

mitigated_by

c7 drafted · lead Proper cable routing

Keep network cables well away from AC cables. For PLC, keep low-voltage AC cables away from medium-voltage AC cables when they run in parallel, cross them at 60 to 120 degrees, and keep cable trays from different box-type transformers apart.

review note: support check: partial - Routing guidance is stated, but 50 m network clearance and the PLC LV/MV spacing are not explicitly tied as mitigation of PLC interference; also the grounding passage mentions routing generally.

c8 drafted · lead System grounding scheme

Grounding the communication device properly and routing cables correctly limits emitted interference and susceptibility to it.

Data