Solar 3 phase kva limit

[Sparkyrob]

My client wants to install a 100kw solar system. He has 3 phase and 100 amp fuse installed on 200kva transformer.
Is 69kw the limit on 100 amp fuse or can he go over without a limiter fitted?
Thanks

 

[bill01803]

Speak to the DNO they will advise you

 

[plugsandsparks]

You will have to plan for all eventualities. So lets say batteries, if any, are fully charged, the property loads have dropped to low, EV's are fully charged etc, this typically happens on a Sunny, warm day. So an export controller will be the only way to stop the supply fuse blowing. You may also find the DNO will have a view on export limit as well, which may be lower than the fuse size.
I have installed a 56KW system on a TP 100A supply and i have limited the output to 11KW feed-in.

 

[Sparkyrob]

Speak to the DNO they will advise you

yes. Will do. Thanks

 

[Sparkyrob]

You will have to plan for all eventualities. So lets say batteries, if any, are fully charged, the property loads have dropped to low, EV's are fully charged etc, this typically happens on a Sunny, warm day. So an export controller will be the only way to stop the supply fuse blowing. You may also find the DNO will have a view on export limit as well, which may be lower than the fuse size.
I have installed a 56KW system on a TP 100A supply and i have limited the output to 11KW feed-in.

I’m sure DNO have said 23kw per phase. Which is 69kw. I will speak to them. I think an export controller will be the best option. The inverters usually have built in export limits but if the limit is set on the inverter at 69 kw and the property use 9 kw does that mean only 60kw goes back into the grid? or is it better to have a separate export controller and set that at 69kw so They can export the maximum amount set by the DNO?
What happens if we limit it at 80kw, will the fuse blow?

 

[plugsandsparks]

Check the inverter specs or post the model, if the inverter spec is suggesting a CT clamp on incoming tails, then its likely it can monitor grid export and control at that point, so the property can consume as much as it likes, the whole 100KW if necessary with the inverter just backing off when it sees excess feed in. Don't design it to push the fuse over 100amps, its pretty damaging when they blow to all equipment in the property and DNO may get fed up coming out to replace it. It it were me i would set the export limit to either DNO stipulation or if they are silent probably around 75 amps max. The inverter has to maintain stability so export limits often go slightly over or under , its not an exact tracking of output. In addition, unless you are getting substantial feed in tariffs from energy company, there is no point exporting the maximum, the inverter will be less stressed if it is limited.

 

[Sparkyrob]

Check the inverter specs or post the model, if the inverter spec is suggesting a CT clamp on incoming tails, then its likely it can monitor grid export and control at that point, so the property can consume as much as it likes, the whole 100KW if necessary with the inverter just backing off when it sees excess feed in. Don't design it to push the fuse over 100amps, its pretty damaging when they blow to all equipment in the property and DNO may get fed up coming out to replace it. It it were me i would set the export limit to either DNO stipulation or if they are silent probably around 75 amps max. The inverter has to maintain stability so export limits often go slightly over or under , its not an exact tracking of output. In addition, unless you are getting substantial feed in tariffs from energy company, there is no point exporting the maximum, the inverter will be less stressed if it is limited.

Thanks for your input and suggestions.