https://www.faa.gov/airports/environ...Guide-2018.pdf
I do know V.C. Bird Intl., Antigua, has installed a large solar array alongside the approach to RWY07. No ILS there, but there is a VOR (same radio band) on the other side of the runway.
Most references I see to RFI from solar array inverters are very localized (as in, within the same building) - and usually it can be suppressed with ferrite chokes on the inverter cabling, and proper grounding of the inverter (to the literal GROUND, NOT to the building - which can just turn the whole building into an antenna!)