If say a result first, nothing improved yet.

More evidence(users) are complaining Ehphase IQ7+ Inverters are showing Random Produciton Drop with 'No Grid Profile' error with Firmware v4.27 or v4.28. I have thought firmware v4.28 can resolve the issue, but, not.

Now, I decide to change wiring for all inverters to check the difference.

This is the current layout, there is no issue at Rear Roof, Only issue at Front Side Upper/Lower Roof.

So, I just try to simplify the front root layout.

This is the current layout, 

i have updated the layout as below

(1) rear roof  - I have reduced the Q-cable length by 4'

(2) front roof - change the wiring, and reduce the power on the wire by half. the length has reduced by 4'. and, it is a new wire from roof to load-center usung 10 AWG THHN-2, have installed an independent breaker. 

(3) porch - direct to JB, No more path thru on front roof panels, so, the power path have reduced by 12'

Base on my calculation, this change has lmproved for the voltage rising and interference of panels (inverters). 

The first day of test, I cannot find any noticeable difference. actually, the inverters are showing error continously. (OTL), but, I wish to compare the difference before/after the layout changes (if there is any improvements)
 

1. Will getting worse

2. Not related with GRID - no need to check grid or profile

3. Just power on reset - at first power on reset, it is showing 'Grid Instability Error' because no grid profile

https://support.enphase.com/s/question/0D52G00004ZVmwjSAD/anyone-else-having-issue-with-some-of-their-iq7-microinverters-randomly-dropping-out-around-the-same-time-every-day

https://support.enphase.com/s/question/0D53m00007P62ncCAB/grid-instability-issue-anyone-have-similar-issue-

I have requested a detail information abut LCF-064-1P,

     Enphase - datasheet only

     Manufacturer - can not provide it because customized item

No more solution with LCF, I have decided to return the filter on Enphase,

I am not sure the part is no good, or filtering is not enough. 

So, I start to find the solution on my way,

I have reinstalled RP230-30-10-S and GTX-2300

    BUT, it has too high line loss, so, I have disassembled & checked GTX-2300.

    the coil configuration is the two-in-hand winding, it is good for common mode filtering, But, it has lower magnetic 

leakage, so,not good for differential mode filtering. it is not much useful for me.

    so, I have removed it. and, reduce 0.5mA leakage current & 10mOhm Resistance Loss

        RP230-30-10-S have 60dB 50/50 insertion loss, but, can not block

the signal from next door also, I guess, my noise level at my home is too quiet and no one use PLC devices.

Yes, high SNR, so, just Envoy signal can be detected too easily.

      so, I have decided to add an extra differential mode filter using ferrite

Ferrite core is B64290L0082X065

and, look the wire direction, it is the coupled differential mode, and 2 turns.

over one day, it can isolated successfuly, the expected core loss is 200-300Wh per year. 

it is much less than 1~2kWh in GTX-2300-Y02. 

This configuration will be saturated under 10A. so, I have tried on single turn. 

at least, I need 20A because higher current will act as a noise, and will reduce the sensitivity of enovy.

and, I just need this inductor is working at the lower current (quite) zone.

This is final configuration.

It is working well, now, my system has been isolated completely.

and, no more cross-domain-traffic issue.

The cost of Ferrite & RP230 filter is just $80, and under $100 include tax & shipping.

It will working when system current is under 24A (around 20, IQ7+),

If want to apply on the bigger system, need bigger filter