Two questions about solar panels.

[JohnW2]

The Loss of mains mainly seems to be suggesting vector shift & rate of change of frequency as the methods used

Thanks. Yes, having been doing a bit of Googling, it seems that those are the two main methods of detection of grid power loss. For example, look at this one .

As you will see, in their 'Conclusion 2' at the bottom, they admit that neither of these methods will detect mains loss in the sort of scenarios I have been postulating. They say that, because of this, DNOs require a "minimum import or minimum export", but I don't really understand that. I can't see how an individual inverter could possibly know whether it was exporting to the grid or to other local loads. Nor do I really understand how it will know about any 'importing' but, even if it did, I'm not sure how it would know whether the import was coming from the grid or other local inverters. As always, I must be missing something!

It looks like I need to continue my reading!

Kind Regards, John

 

[westie101]

I would have thought that they would continue to synch to one another for a potentially appreciable period of time before they (jointly) started drifting

Within the type approval testing requirement, this situation (as I expected it would) iappears to be taken into account and the disconnect requirement is stilll the same.

 

[JohnW2]

I would have thought that they would continue to synch to one another for a potentially appreciable period of time before they (jointly) started drifting

Within the type approval testing requirement, this situation (as I expected it would) iappears to be taken into account and the disconnect requirement is stilll the same.

One would certainly hope so, but the 'how' question would still remain. We also have that link I posted (and others similar) admitting that , in certain circumstances neither phase (vector) change nor rate of change of frequency will detect grid failur - so I guess there must be some pieces of string or safety pins, as well as those two 'belts and braces' involved, if the inverters can pass the tests under the sort of conditions we've been discussing.

Kind Regards, John