SolarEdge operational question

[ButchDeal]

Perhaps each optimizer just keep pushing up its output voltage until until enough power is drawn to put
its panel at MPP. The inverter could just keep taking more energy from the optimizer string until the
total voltage drops to around 350V. The potential for instability is high.

possibly something like that but the optimizers spit out higher voltage than they take in usually.

[jflorey2]

Perhaps each optimizer just keep pushing up its output voltage until until enough power is drawn to put
its panel at MPP.

Except this is a two-quadrant optimizer; it can increase or decrease voltage and still be at MPP. So it needs a target.

also it tells the optimizers very quickly the opposite, (rapid) shut down now

If it's failsafe (and I expect it is) the inverter may drive the shutdown by NOT telling the optimizers anything for some time (10 seconds?) If the optimizers hear nothing for a while, they shut down. That way a loss of power, or disconnect, or fatal SW bug causes a shutdown automatically.

Although earlier Solaredge installations need a big relay to achieve 690.12 compliance, so maybe not.

[adoublee]

Although earlier Solaredge installations need a big relay to achieve 690.12 compliance

A big relay to achieve 690.12 compliance? That's news to me.

[jflorey2]

A big relay to achieve 690.12 compliance? That's news to me.

Google "Solaredge rapid shutdown kit."

Edited to add - never mind, I'm wrong. The kit is just a new cable set with a new gadget on it. I assumed the switch had to be replaced as well so I assumed a relay, but it's just two cables in the inverter that need replacement.

[ButchDeal]

If it's failsafe (and I expect it is) the inverter may drive the shutdown by NOT telling the optimizers anything for some time (10 seconds?) If the optimizers hear nothing for a while, they shut down. That way a loss of power, or disconnect, or fatal SW bug causes a shutdown automatically.

The shutdown command could and clearly is lack of communication as you are disconnecting the optimizers form the inverter with the DC disconnect to engage it.
My point is that they are clearly getting some communication on a much faster bases from the inverter to operate.

Although earlier Solaredge installations need a big relay to achieve 690.12 compliance, so maybe not.

The rapid shut down kit was just a wire with built in resistor. Not sure what you mean by a big relay.

The inverters all have it built in now.

[ButchDeal]

Google "Solaredge rapid shutdown kit."

The shutdown kit is 5 sets of wires good to converter 5 older inverters. One wire has a resistor.
It is and has been built in to all the inverters for some time now though.

http://www.solaredge.com/sites/default/files/rapid_shutdown_kit_for_single_phase_inverter_installation_guide.pdf

[adoublee]

Google "Solaredge rapid shutdown kit."

It's a firmware change and cable replacement in the DC switch (incorporated into inverters shipping now I believe). No big relay.

[bcroe]

Except this is a two-quadrant optimizer; it can increase or
decrease voltage and still be at MPP. So it needs a target.

Yes I'm suggesting the target is to take enough energy from the panel (and deliver it to the inverter
string) to put the panel at MPP. For example if the optimizer output is 28V @ 8A (224W) but the MPP
would deliver 240W thru the optimizer, the optimizer will jack up its output to 30V @ 8A to get on MPP.

If the inverter sees the string voltage getting too high, it will pull say 8.2A and the optimizer above
will adjust to 29.3V out to get back on MPP. Bruce Roe

[solarix]

Yes, the inverter communicates with the optimizers, but not for the purpose of running the optimizer's control loops.