1 central or multiple string inverters for 50kW system

[solgen]

Does anyone have an opinion on the route to go for a 50kW system that either has 1 large central inverter or many smaller string inverters? My immediate thoughts are:

1. If some of the panels or inverters drop out then at least remaining parts of array will produce energy for a system that uses string inverters.
2. Easier to locate string inverters by placing them on the PV mounting poles.
3. Central inverter will require some heavy weight kit to locate it.
4. Central inverter out of doors in a field will require a purpose built building to locate it in.

Does anyone have a preferred solution for a 50kW using multiple inverters or a central inverter i would appreciate your thoughts

Thanks

 

[Worcester]

It depends upon the specifics of every case, there is no single answer.

Bear in mind that a lot of central inverters only have a single mpp tracker!

It wont be that heavy, only a couple of hundred kilos or so, so a normal bit of lifting gear should do it (get a trained operator), even sma 17000TL's weigh 60 kilos each, so you need three people to safely lift one of them any way.

Shed load less AC wiring with a central inverter

Will need to look at protecting the DC cable on the longer runs.

Horses for courses ... No right, no wrong. Check the quality of the central inverter - which make are you considering?

 

[solgen]

Hi,

Was thinking of using either 5 x Sunny Tri -power 10,000TL

or

Fronius CL 48 (not sure really as don't have an immediate supplier for these sizes of inverter). I welcome any suggestions.

Thanks

 

[access_renew]

We can assist with the supply of Fronius and Eltek Valere central inverters - both of which have UK support available on large projects. Let me know if you would like some prices on these.

Sean @ Access Renewables

 

[JD6400]

Hi Solgen

I was in the opinion until recently to go for multiple 10kw inverters over a central one , but now would go for a central one .
The reason being as already mentioned the requirement of less ac cable and switch gear , depending on the make , how easy and relatively cheap it is to replace individual modules in them without loss of production and when used with string controller's how well they are at detecting a fault and where it is in the system .
Also the ramp up efficiency and ability to fire up on a different module each time plus there ability to over come some shading issues if thats how you have designed the system .
And installation time and the room required is substantially reduced .

 

[daytona600]

central inverters have many features , system/module monitoring , wind/temp/yield sensors , simple to scada functions , module theft detection
automatic de-icing/snow removal , webservers/datalogging , pv displays , high effciency to 98% , universal crystalline/hybrid/thin film modules with transformer/transformerless
simple to complex , , comms 20kwp to 1.6MWp in LV & MV outputs indoor/outdoor to fully containersied with switchgear
PM me if pricing required - central/string/micro/de-centralised

 

[whlphil]

I'd go with 3 x SMA 15000TL integrate your DC surge with the plug in modules, electronic string fusing built in, all of that shows up on the webbox daisy chain the three together for monitoring. Take the 3 to an AC sub dis then back to your main board stopping off at your G59 contactor on the way.

 

[BruceB]

15000TL can be set to G59 already, so surely another G59 contactor is not required?
Regards
Bruce

 

[whlphil]

15000TL can be set to G59 already, so surely another G59 contactor is not required?
Regards
Bruce

Afraid not most DNO's ive come across so far want one point of G59 cutoff so demand an additional separate board. The inverters cant be set to intertrip either, if any one knows a better way I'd be interested to hear it?

 

[JD6400]

Just had two fronius cl 36 inverters wittiness tested today , they have g59/2 in them but western power wanted separate relay .
Even had to open up the ones in the cl's so they did not compete with the brought in one !
Crazy !!!!

 

[whlphil]

DP we are currently arguing with CE over the same I know we are not going to get anywhere but I'll have a go! SMA are aware and trying to sort with ENA

 

[BruceB]

I would like to see a reasoned electrical argument for disallowing distributed G59 protection. I am coming to the view that the DNOs are taking advantage of their monopoly position.
Regards
Bruce

 

[whlphil]

I would like to see a reasoned electrical argument for disallowing distributed G59 protection. I am coming to the view that the DNOs are taking advantage of their monopoly position.
Regards
Bruce

Yep fully agree, whats the point of having a standard but then saying 'ah well if one trips then the others might not' if it meets the standard it meets the standard.

 

[JD6400]

To be honest we by no way skipped on the quality of the G59 panel , but i would bet my last £ that the one's we opened out / disabled in the cl36's were of a far Superior quality .
Like i said before crazy !!!