do you have to apply for DNO permission if having a SMA 4000tl inverter?

evomatt

Ive just been told that if i want a sma 4000tl inverter the fitter would need to apply for DNO permission but a SMA 3600TL is fine. Is this correct? Its on a 4Kw system

ChopperST

Yes.

You can connect up to 3.68kW for a domestic application and simply notify the DNO.

Systems larger this this need to be prior approved.

http://www.energysavingtrust.org.uk/Generating-energy/Choosing-a-renewable-technology/Solar-panels-PV/Connection-to-the-grid

evomatt

So If ive got 16 x 250W panels which in theory should produce 4000w at peak but an inverter rated at 3600w will i be loosing out on anything or is it unlikely ill be producing over 3600w?

Im like a big kid getting a new toy so dont want to wait 45 days waiting for the DNO approval. But if it means i can produce alot more then i might wait.

Sorry if the above sounds a bit thick but i am when it comes to this (ive already been picked up on Kw and Kwh

EricMears

ChopperST wrote: »

Yes.

You can connect up to 3.68kW for a domestic application and simply notify the DNO.

Systems larger this this need to be prior approved.

http://www.energysavingtrust.org.uk/Generating-energy/Choosing-a-renewable-technology/Solar-panels-PV/Connection-to-the-grid

Of course if you're only fitting 3.6 kWp of panels you could fit a 4kW inverter (or even a 10kW one if you were particularly silly).

But getting DNO approval for a marginal increase over the 'magic' 3.68 is unlikely to be a problem. As I'm sure I've said before in other threads, most DNOs are confident they could supply you with 15 kW so how could they possibly say that your 4kW would overload their system

Martyn1981

evomatt wrote: »

So If ive got 16 x 250W panels which in theory should produce 4000w at peak but an inverter rated at 3600w will i be loosing out on anything or is it unlikely ill be producing over 3600w?

I've been following this for some time, and watched the advice from my DNO (WPD) change. Way back, they were willing to take the inverter efficiency into account, so for a 4kWp system, you'd only need prior permission if inverter efficiency was greater than 92%.

Then they brought in 16amp caps (3,680W at a nominal 230V), then in came the actual 3,680W caps as voltage in the UK is often much higher than 230V.

You could probably have the 4000TL as long as the installer set it to 3,680W max (most (all?) SMA's can be set, and in 1W increments) then stated this output on the DNO notification. This might be useful to anyone installing say 6kWp (split E/W) and using a larger inverter, perhaps 5kW to make sure voltage was within inverter parameters, but operating to a 3.68kW output limit.

So lots of fun and games.

Don't worry about total generation, a slightly smaller inverter will come on at slightly lower levels, and hopefully be a little more efficient when generation is lower. This should make up for any losses at peak. Plus, as panels get hot, they'll quickly drop 10% anyway. In the UK, it's often suggested to undersize inverters by 10% (even 20%) but would depend on orientation and location.

Mart.

JTPR

evomatt wrote: »

Ive just been told that if i want a sma 4000tl inverter the fitter would need to apply for DNO permission but a SMA 3600TL is fine. Is this correct? Its on a 4Kw system

This is correct.

Kernel_Sanders

EricMears wrote: »

most DNOs are confident they could supply you with 15 kW so how could they possibly say that your 4kW would overload their system

I don't get this, Eric. I thought that the DNO restriction was so that the PV input arriving at each sub station would never exceed the demands of everyone supplied by the sub station. Even if this is not the case, what relevance is the demand that you referred to (i.e. 15kW)?

EricMears

Kernel_Sanders wrote: »

I don't get this, Eric. I thought that the DNO restriction was so that the PV input arriving at each sub station would never exceed the demands of everyone supplied by the sub station. Even if this is not the case, what relevance is the demand that you referred to (i.e. 15kW)?

Most people have a "board's fuse" alongside their meter. They're usually at least 60A; more often than not 100A. 60A @230V would be 13.8kW; 100A would be 23kW.


But I'm afraid the "total supply of the substation" hypotheses is wrong too. Our house is supplied directly from an 11kV main via a dedicated transformer on the nearest pole - which must mean that the total number of consumers on 'our substation' is one.


Afraid I've yet to see any convincing reason for the existence of any limit to an individual household's export. However much you shove in at one point on the grid, the very existence of the grid should mean that it gets evened out. In our case, anything I export at 230V (though it's actually nearer 240V) would get transformed up to 11kV (and back down to 230v in the next transformer along the line) before any neighbours get a chance to use any of it. In the (highly unlikely !) scenario that I managed to supply everyone else on my 11kV supply line then my excess would just get pushed up to the next supply voltage and spread even more widely.

travellerboy

I have a 4000TL definitely an improvement over the 3680TL and has no convection fan. No noise !!
Also the newer model 4000TL is Wifi enabled as distinguished from Wifi capable. Externally the Inverter will have a Black antenna located at the bottom left hand side. As a result no cables connecting your PC or laptop and you can access from anywhere.

zeupater

travellerboy wrote: »

I have a 4000TL definitely an improvement over the 3680TL and has no convection fan. No noise !!
Also the newer model 4000TL is Wifi enabled as distinguished from Wifi capable. Externally the Inverter will have a Black antenna located at the bottom left hand side. As a result no cables connecting your PC or laptop and you can access from anywhere.

... as opposed to using the class 1 Bluetooth on the TL-20, so no cables needed without Wifi. Whichever comms method is enabled, it would be wise to ensure that the standard (as shipped) passwords are changed ....

A meagre 14W being produced at the moment and I know this despite having no cables between the room I'm in and the garage where the inverter is .... also get alarm/warnings delivered to where we can actually notice them !!

HTH
Z

Kernel_Sanders

travellerboy wrote: »

I have a 4000TL definitely an improvement over the 3680TL and has no convection fan. No noise !!

It has a fan which comes on when the ambient temperature approaches 30°C.