2 questions:
1) does your PV production ramp evenly from 100% to 0% as frequency goes from 59.9 to 60.4? Or is the ramp-down uneven?
No, my inverters are just configured to shut off at 60.5, so they were at 100% until it hit the cutoff frequency and then they just shut off.
As I mentioned above (or maybe in another thread) it is possible to configure the solaredge inverters to ramp down as the frequency increases, but when I tried configuring this I didn’t really have any success, I think it may be possible to get it to work, but I would first need to change the shut down frequency to something higher than 60.5Hz. There’s just not enough resolution between 60Hz and 60.5Hz to really effectively ramp down.
Especially since I really wouldn’t want the ramp down to start until around 60.2Hz at a minimum since it’s possible for the frequency to vary slightly even when things are operating normally. I wouldn’t want the inverters to start ramping down and lose 20% of my solar production because the utility frequency happened to be a little high.
2) We know that PWs seem to be designed to allow the PV to continue production uninterrupted immediately after an outage provided the PWs are not at 97+%. However, if the PWs were below that level, I wonder if the level of charge correlates to the frequency. For example, if PWs were at 30% when outage occurs, then perhaps the frequency would remain at 60Hz immediately after an outage; however, if the PWs were are 90% when the outage occurred, perhaps the frequency would be raised to 60.3Hz to keep the PV producing albeit at a lower level?
It does, but the range is much narrower than what you are thinking. The frequency starts to rise at about 97/98%, so below that it will always be at 60Hz, and then from about 98% to 100% it will evenly go up from 60Hz to the max frequency.
So if the max frequency was set to 62.5Hz and the powerwalls were 100% charged the frequency would jump to 62.5Hz at the time of an outage. If the powerwalls were 98% charged the frequency would only go up a little, to around 60.2Hz. If the powerwalls were 99% charged then the frequency would go to around 61.3Hz.
It’s also worth noting that the frequency rise would be linear.. it wouldn’t jump from 60.2 at 98% right to 61.3 at 99%, it would go up to 60.3, then 60.4, then 60.4, etc as it gets closer and closer to 99%.
Finally, it’s worth noting that Tesla does not seem configure the PV systems to ramp down. Even though the powerwall and the inverters do support it Tesla just configures them to cycle on and off. As I’ve stated before, while ramping down might be a slightly more elegant solution I’m not sure that there’s really a big benefit to it.