Note: This conversation has strayed off-topic. I believe the OP was asking about surge protection, not fusing. I also believe he said there is only one string.
The problem is my question was one from my own broad ignorance. It is not easily answered.
There is general PV to equipment protection (1), at the first level. Thank you for everyone's extremely thorough answers.
For (2), those of you unfamiliar, 'Professor' Ben Davidson has written several books. He's professor-level but very relatable, not wrapping terms in unnecessary levels of difficulty to protect a job, career field, etc. {He could be a prof at a uni, but has chosen instead to get his message out directly. One of his books is used at unis.}
I have watched coronal mass ejections/flares at the X100+ level leave the sun - not in earth's direction. That is a 'kill shot' that would fry the grid, and do damage to off-grid systems. Although I don't know how to protect from it.
They are not yet at the scale of the solar micronova predicted between 2035-2045, which is why Bezos and Zuckerburg are building the giant underground centers, and why the Air Force has been involved in building similar structures since the 1940's. One of those X100, roll of the dice, may hit earth between now and then, anyway.
This micronova is much more severe, at a once-in-12,000 year event level. It is the blow-off from an accretion layer, that is built-up from sol passing through the center of the galactic wave-patterned sheet. Out here, the wave has longer, more open oscillations. Every 3,000 years there is some level of interaction. Every 6,000 years a stronger event, and every 12,000 (12,068) a much stronger event: the so-called Black Sun. Where there is enough microparticulates in the wave, to envelope the sun, which it eventually blows-off, leaving the 'pale rider', a yellow-green colored sun. The 'hell follows with it' part is the shell buildup hitting the earth, with the micronova blast.
Ref:
Thomas Chan, Adam and Eve Story (uncensored scan)
https://libgen.rs/book/index.php?md5=F3FC7FA0973FC52E973047B181CF5263
Ebook version
https://libgen.rs/book/index.php?md5=85DEF30907FEA6E6174EE28E87C210F8
World In Peril, by Ken White, grandson of Major Maynard E White: