in the case of a grid-connected system, a short circuit means that we will have, at most, the panel’s Isc, which does not pose any problem for the cables. We install a fuse because, if there are several strings, the reverse current that could flow through one string must not exceed the maximum current allowed by the blocking diode, so we protect it with a fuse.
however, with batteries, there is generally no system to prevent a battery short circuit from being fed back into the PV system. In this case, therefore, the current is much higher, and the cables must be protected!
so, to be precise, it isn’t high voltage; we’re simply moving from ELV to LV.
There are currently a huge number of installations using LV (I think it’s the most commonly installed), and all the major hybrid inverter brands (Huawei, Growatt, Solax, etc.) are often LV, so there are no problems. Many installers are already installing them!
Now you’re going too far… not many people know or understand the permissible reverse current of a PV module (I’m not throwing stones at anyone: I’m still learning, and there’s a lot to learn), and even fewer will read this specification in their PV module documentation (if they read the PV module documentation at all, that’s already something… RTFM…)
Even though it’s important and easy to explain.
A generator that delivers less than another generator in its string becomes a load (and all that, and all that…) (well, I’m simplifying a lot, because Kirchhoff’s current and voltage laws and all the other delights of the subject do actually have to be studied)
Yes a fuse or breaker per string can help protect when there are three or more parallel strings in play.
But it will never function to protect for a single non parallel string which is usually the case for the 450-600V class trackers? Sure an imo disconnect or mnepv 600V breaker is useful as a convenience disconnect but the current can never exceed the fuse.
For my 450/100, no parallel strings just a 5x400W and a 9x375W string. Pv current less than 15A. No fusing.
For my 250/100 and 250/85 with 5s4p and 3s3p? Absolutely need fuses or breakers per string because now pv current can be up to 42A. I use inline mc4 fuses and Staubli branch connectors for the paralleling.
In principle, yes, but it’s a requirement of the French standard!
With a battery, even if there’s only one string, fuses are required because, as explained, overcurrent from the battery on the PV side must be prevented!
Are you saying there should be a fuse on a single non parallel pv string on the hs19 to protect against some failure mode where the hv battery current reaches the pv input and send some surge to the panels? Is that in the manual?
This seems impossible to happen? No internal protections?
