For several years I've been researching why my Solaredge inverter was tripping, mostly from 10AM to 2 PM during sunny days and usually during cloud edge peaking. I started seeing "ARC Detected" on the inverter alarm log using Setapp. I have an SE7600HD and a 7.04 kw system with 20 panels. These trips could be hard to notice just using Solaredge Monitoring unless you have the "Analysis" screen. I'm sure not everyone has access to that. What I noticed on sunny days and sunny days with cloud edge effects, that the inverter tripping was correlating to optimizer power drop-outs. Inverter trips also, obviously, caused optimizers to drop out. They have 5 minute resolution and all read at different times. Doing more digging I discovered that the inverter has an AFCI (Arc Fault Correction Interuption) feature and that feature was enabled by default. SE manuals talk about arc fault detection and that if it trips it locks the inverter. Only thing I saw was a trip and auto-restart, so that lead to some confusion! Doing even more research I discovered what the AFCI system was looking at. Initially I thought it could be affected by the AC distribution and it may have some input, but mostly it senses the DC current from the strings. An arc causes current to swing wildly. When there are cloud effects going on causing wild DC input current swings is when I finally realized the inverter may be too sensitive to the swings. After several days of hand ringing I decide to disable the AFCI feature. Since then, no more tripping on good no cloud days, and no tripping on cloud edge effect days. I have a Support Case open with Solaredge to address the issue with the AFCI algorythm. Having the AFCI feature disabled is when it became more apparent that several optimizers were dropping out even on perfectly sunny days. 8 of my 20 panels are 370 watt bi-facials and I have seen them output 440 watts during cloud effect days. When I installed them, SE said they would warrant the P401 optimizers as long as the front side rating of the panels was less than 400 watts. It is of my opinion, that the power spikes have affected several of the higher powered optimizer locations. SE has RMA'd me one P401 optimizer and that one was hard to get. It helped! They test fine on the bench, but have issues at higher power (usually > 300 watts and even < 400 watts, much less >400 watts!). I have a ground mount system, so not having the AFCI feature enabled isn't going to burn my house down, but I do want the protection that it affords. Waiting for a response from Solaredge. I see no way to make any tweaks to the sensitivety. I'm, also, looking at upgrading from P401 optimizers to S440 for the higher powered locations. Some P401's are rated at 10.75 amp input and others 11.25 amp input. S440's are rated at 14.5 amp! Left screenshot is with AFCI enabled. Right screenshot disabled. Sorry a long read.
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