15-20KW Grid connect turbine recommendations.

[batat]

Hi,
I'm considering installing a large grid connected turbine with a view to exporting the surplus generation. Having been 'lurking' here for a little while I find myself pondering which system/company to contact for a system. Others have suggested that Navitron no longer sell larger units (5kw+) with others suggesting that the quality leaves a little to be desired which would be worrying to say the least on such a large turbine. Are these comments on the quality of Chinese manufactured turbines without foundation?
Grid tie inverters: if I understand correctly these large units output 'wild' a/c at high (400-600v) voltages. As none of the Chinese manufactured G.T.I.'s have G83 certification are you stuck with using multiple units of USA origin which others here claim are unreliable & too small?
Or am I missing something fundamental to the working of these large capacity turbines?

Does anyone here own a 10KW+ turbine (ideally 20KW) who'd care to share their experiences on or off list?
It's a lot of money to invest in the wrong stuff!

Thanks & regards,
Batat.

[Ted]

The SMA inverters are made in Germany. I don't think there is anthing inherently unreliable about them - it's just that they are basically designed for PV installations not specifically for wind turbines so may be a little less efficient than they could be. If you have a really good wind site (if you haven't then a 20kW turbine isn't a good idea) then the losses will be pretty minimal. You need to ensure you have over-voltage protection designed into the system.

The size of turbine you are talking about will need to be installed under G59 (G83 at the discretion of the DNO if they are happy with it) so the first thing you need to do is talk to your DNO to find out if your local grid infrastructure is up to supporting such size of turbine and whether they will charge you anything for the privilege of connecting it. This could completely screw the economics of your plan.

[Alan]

Large ones can be made cost affective if you have the resources available.

I would suggest that modifications are made to correct the considerable design defects before any attempt is made to commission a large Chinese turnip.

Topic It Broke

http://www.navitron.org.uk/forum/index.php/topic,860.0.html

With lots of Luving care and attention they can be made fit for purpose.
They require substantial modification to front and rear bearing plates, alternator casing, alternator casing to rotation device, removal of internal gear boxes and motor, replacing cast iron hub with fabricated mild steel hub and complete balancing of the entire rotor / blades.

This was the rotation device used in the 10 K.W. one
A gear made of very soft
( ??  mild steel ?? ) that was welded inside the generator hub with no means of adjusting the play between the worm and wheel gear.


http://www.steamboilers.homecall.co.uk/300.jpg

They can be modified to turn the device into / out of the wind from the ground using substantial gear boxes. It takes five minuets to complete one revolution.


http://www.steamboilers.homecall.co.uk/292.jpg

The gear box mounting plate consists of 40mm steel plate with the tower supports made of 40mm round bar mounted inside schedule 80 thee inch pipe supports.


http://www.steamboilers.homecall.co.uk/293.jpg

The base only differs from the proven design in so much as they use male bolts that wind into female holes sunk into the steel work of the concrete base. Not so bad if you remove the bolts at regular times to inspect for corrosion problems. With my modification the complete steel structure is welded. The only nuts and bolts are the ones used to bolt the tower to the hinged base.


http://www.steamboilers.homecall.co.uk/294.jpg

The foundation is similar to the proven design


http://www.steamboilers.homecall.co.uk/233.jpg

Finished turnip


http://www.steamboilers.homecall.co.uk/270.jpg

Inverter design problems, leave that for another day.

Regards

Alan

[batat]

The SMA inverters are made in Germany.
You need to ensure you have over-voltage protection designed into the system.

The size of turbine you are talking about will need to be installed under G59

Ted, Alan, thanks for your replies.
Looks like I got the wrong stretch of water for the SMA. Corrected.
Surely the control system provided with the turbine would have over voltage protection built in?
Do SMA make inverters of suitable capacity for these larger units then? And while I think about it is the same technology applied to the big 60KW units?
As you've probably gathered I'm not too familar with the Gxx specifications but from reading your reply a smaller 15KW unit may be a more practical option thus not stepping into the next price bracket. I notice that the largest unit from Proven (to my knowledge)  is 15KW maybe for this reason?

Nice photos Alan

Thanks.

[dhaslam]

When comparing size you need to compare at the same  wind speed.  At 10m/s the Proven output is about 13kw.  Although it is expensive there is an advantage in installing a system with a full guarantee.

[paulg25]

G83 allows for 16 amps per phase, so on a single phase system this is 3.8KW.  I am trying to get hold of my DNO about connecting a 5KW turbine to the grid via a 6KW inverter.  This can output up to 26 amps into the grid but will probably average out at around 4 amps.

I have not looked into 3 phase systems but I assume you can connect an 11.5KW system under G83.(16 amps per phase).

For what it's worth, I am looking at getting a Magnatek Aurora inverter.

[Ted]

I have not looked into 3 phase systems but I assume you can connect an 11.5KW system under G83.(16 amps per phase).

In theory, yes. But unless you already have a 3 phase supply to your site it would likely cost way too much to run it in.