>
> The array is still just as live and dangerous with the switches open
> and the sun shining through heavy cloud.
>
> Even moonlight is enough of a worry.
>
> Voltage remains near max to well below full sun - almost certainly about
full V at 5% sun. That's a cloudy not totally darkened day.

Somewhere around there you come off the more or less constant current
plateau and probably go down V approximatly linearly. So say 5000 lux =3D
100% V and 1% per 50 lux below that. Brightest of moonlight should be safe.
Would be interesting to test.

The purpose of the isolation switches is to allow safe work on the
> inverter, or the grid side of the inverter.  Safe work on an array
> remains a challenge.
>
> A good safety measure, once you are SURE that mains is gone, is to short
every panel. You get Isc max and no panel damage. However, this is liable
to be very hard to do even with industry standard plug and socket
connections. More likely available is shorting the whole array or subsets
thereof.  In a say ~=3D 100V system that about 10A/kW which is easy to clam=
p
down if done properly.

Microgrids with inverters providing 230 VAC out per panel will be
"annoying" . Technically these should be anti-islanding with no Vout
without mains present - but I'm not sure how they enforce not having them
all 'sing to each other'.



           Russell
--=20
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