Refused Connection

[jason121]

The idea would be to switch of each individual inverter relative to output current but keeping in the DNO limit of export. Also would be good idea to rotate inverters to keep same number of hours usage.

 

[Worcester]

Speak to Andy he can put you in touch with the G59 Panel manufacturers, works excatly that way, drops out the inverters one by one to keep below the value.

That's the advantage of multiple string inverters of a central one

Of course it would be nice if they could monitor them all, look at the generation. load and limits and choose which one to drop next , that would be too clever!! Instead at this point in time you'll have to choose in advance and set the order up based on your knowledge of their likely load levels and typical generation - hence our half hourly analysis - only took about 8 hours to do.

 

[jason121]

I make my own G59 panels. Just need to find the right current limiting relay. SMA do one and like the idea of the elios, but that's limited to 50kw.

 

[SibertSolar]

FYI, 4-Noks are going to port across a similar system to the Elios PRO that they use in mainland Europe that allows export management for up to 200kW (maybe 250kW) systems, with security/lockout of parameters. It's an available solution but just not yet configured for the UK market. Would be handy to have an idea of potential demand though, although I know personally of multiple situations where this is required, and will probably be more frequently required as the grid gets more and more saturated.

The electromechanical solution that Worcester refers to is a valid option that is almost 100% fail safe but it's primitive in that it switches off inverter(s) completely. Most modern European manufactured inverters have a facility to throttle their output to a preset % of peak power, in several steps - something that the German/Italian/Spanish grid operators do remotely if required (or managed by 3rd parties according to grid demand etc). We have somewhat different challenges over here to facilitate this kind of control but a closed loop feedback system using something like the P1 (ABB) PMU that Gavin is using, along with an export energy monitor like the Elios can provide a decent granularity of control compared to actually switching inverters off.

 

[Gavin A]

FYI, 4-Noks are going to port across a similar system to the Elios PRO that they use in mainland Europe that allows export management for up to 200kW (maybe 250kW) systems, with security/lockout of parameters. It's an available solution but just not yet configured for the UK market. Would be handy to have an idea of potential demand though, although I know personally of multiple situations where this is required, and will probably be more frequently required as the grid gets more and more saturated.

bagsy

The UK is going to be the biggest market in europe for this scale of installation, in coming years, and export limiting is going to be vital to this development, so the market potential is at least as big as any of their existing markets.

Not sure what it is with EU manufacturers not actually sussing this stuff out tbh, we're a top 5 global solar country, they need to start treating us as such, not like some sort of naughty child that they might give a few crumbs to if mainland Europe leaves anything for us.

 

[SibertSolar]

Completely agree Gavin, I'm working on it!

 

[dingledong]

So if I wanted solar as every one in my street had it, you might not be able to do it as there is already enough going into the grid ?

 

[Gavin A]

So if I wanted solar as every one in my street had it, you might not be able to do it as there is already enough going into the grid ?

we'd only be able to install 16 amps per phase, and even then there's a risk of inverters tripping out due to the grid voltage being pushed out of range. It's going to become much more of an issue very rapidly in the next few years as we start maxing out the existing grid capacity with very dumb controls.

We've now hit the half way point to the 10GWp the grid reckons is the maximum sustainable without any form of smarter control of inverters etc.

Unfortunately nobody has done anything about smarter control of inverters, completely ignoring the lessons from Germany where they've had smart grid control of inverters for several years using the exact same inverters we're installing, presumably because nobody in power has much of a clue about this stuff - I know when we raised this at the G83/2 discussions, it caught OFgem and the DNOs on the hop as they'd no idea what was actually possible. At the time it was suggested this could come in with G83/3 in a few years, but they seriously understimated the speed the industry would be installing at, so in the meantime we've hit half their stated limit while they fiddle with other stuff.

Problem being, the greater the level of uncontrolled inverters we install now, the higher the level of restrictions that will end up being placed on smart controlled inverters later on, which is pretty silly really, and could end up restricting the total level possible to a lot lower than would be the case if we'd started with smart control from 1GWp onwards rather than waiting until we hit 10GWp.

[dismounts from soap box]

 

[jason121]

FYI, 4-Noks are going to port across a similar system to the Elios PRO that they use in mainland Europe that allows export management for up to 200kW (maybe 250kW) systems, with security/lockout of parameters. It's an available solution but just not yet configured for the UK market. Would be handy to have an idea of potential demand though, although I know personally of multiple situations where this is required, and will probably be more frequently required as the grid gets more and more saturated.

The electromechanical solution that Worcester refers to is a valid option that is almost 100% fail safe but it's primitive in that it switches off inverter(s) completely. Most modern European manufactured inverters have a facility to throttle their output to a preset % of peak power, in several steps - something that the German/Italian/Spanish grid operators do remotely if required (or managed by 3rd parties according to grid demand etc). We have somewhat different challenges over here to facilitate this kind of control but a closed loop feedback system using something like the P1 (ABB) PMU that Gavin is using, along with an export energy monitor like the Elios can provide a decent granularity of control compared to actually switching inverters off.

My area has not a lot of capacity left. Solar farms are popping up all over. The cereal farmers can make more money from renting land then actually farming it.

 

[jason121]

I have another 200 kw and 50 kw to install but wont happen until i can find a decent limiting device for both.

 

[Geordie Spark]

The only time I was refused connection was when I came home late stinking of another bird's perfume.

 

[TedM]

Gavin, don't read any of this unless you are prepared to get annoyed. OFGEM has a budget of £100's of millions to address these issues - https://www.ofgem.gov.uk/electricit...orking-groups/decc-and-ofgem-smart-grid-forum and https://www.ofgem.gov.uk/electricit...s/network-innovation/low-carbon-networks-fund

 

[Gavin A]

I'm aware, I've been meaning to get on the case with this, but actual paid work keeps intervening.

 

[tidyboiler]

The only time I was refused connection was when I came home late stinking of another bird's perfume.

Or was it her kebab!!! Probably saved you from a horrific experience!

 

[Gavin A]

My area has not a lot of capacity left. Solar farms are popping up all over. The cereal farmers can make more money from renting land then actually farming it.

now that does nark me, solar shouldn't be being installed on prime agricultural land.