Hi wrenches.
I had an interesting case today that I have been thinking about since it
happened. I dont have all the details because the homeownter had to leave
before
I was done with the service call, but here is what I do know. SB5000 with 2
strings of 15 modules. String one was 437 vdc, and string 2 was 247vdc. I
decided to look for a ground fault, and I turned off the inverter. I measured
for ground faults and found no evidence of anything wrong in that regard. As
the
homeowner was out of time and wanted me to go, I re-landed the wires in the dc
disco, and when I replaced the fuses, I noticed a minor arc when one of the
fuses was going it. Although I had no time to measure it, I think that there
might be a partial short circuit, possibly with one complete string and some
panels of the other string, and the remaining panels on the second string. My
mind was racing with how I could have measured for a partial short circuit
without seeing it as an arch. I can imagine such a thing on a bigger system
being a dramatic electrical event.
needless to say, I cant wait to get back there and go through the signal path
properly and find out what the electrician did. And of course i realized that
replacing the fuses in such a questionable situation was probably not the best
idea.
Do any of you have any thoughts on how one would measure for such a thing?
nick vida
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