Programming my GTI with power curve information

[AIRFORCE-1]

Hi All

Can anyone help me with

I've bought a FD1KW 150V turbine from Navitron and sourced a GTI from China.  The inverter has the facility to program 40 parameters of Voltage to Power but this information is not available from Navitron.  The experimentation route adviced by Navitron isn't acceptable as I have no idea where to start.

So is there any one who could either supply a Volts to Power graph up to survival speed,
or
give me some pointers as to how to go about getting this info?

I could also do with the data for the 2kw 220V unit.

Regards

Airforce-1

[jglockling]

A similar problem. To programme the grid tie inverter requires knowledge of the voltage generation (DC) vs power output (W). I am considering using the Soladin 500 or WindyBoyLV with a 48V 1KW Navitron turbine but I cannot find this information (is it even applicable - is voltage proportional to RMP?). The Future Energy site gives curves for the Soladin 500 and their turbine but I do not know if the Navitron Wind Turbines operate in the same manner.

Please shed some light on it for me please.

Thanks,

Jim

[Ivan]

voltage output of any turbine will depend on the rpm AND the load applied - eg a 12v wind turbine can produce up to 70v if it is allowed to spin unloaded. What you really want to do is match the grid load to the power output. A voltage relationship is one way of doing this, but it would need to be established empically.

BTW, the 1100LV is not a very good choice, unless you have an overvoltage protection circuit.


Ivan

[jglockling]

Thanks Ivan,
What about the Soladin offering? or is there anything else you would recommend? I'm still unclear as to how I work out the voltage / power curve - if it is connected to the grid - is the loading not constant? Would I experiment with simultaneous measurement of wind and change settings until I stalll the turbine? Sorry if this is being a bit dim but is this not something turbine manufacturers would supply?
Thanks, Jim

[Ivan]

The data needs to be collected from a wind turbine/GTI combination. Normally obtained via collaboration between wind turbine manufacturer and GTI manufacturer. It depends on the way the GTI reacts (speed, extent of auto-adjustment to load etc). Mastervolt have shown no interest in working with us, and despite contacting them several times, they have not returned our calls, told us they would inform us when the inverter was available, told us that they would not supply us, etc etc.

You will need to guess a curve to begin with. Then with the turbine connected, check that it does not overspin, stall or oscillate between points on the curve. It's empirical trial and error, although there is quite a margin either way...it is not an exact science. It is also quite time-consuming to get it set up. I have spoken to a few experienced wind turbine installers, who tell me that they have to fiddle with the GTI settings for some Big Name wind turbines, despite the fact that they are supposedly already calibrated


Ivan

[jglockling]

Thanks Ivan,
That's useful stuff. The Mastervolt news is a bit dissapointing. I don't know how sales figures are but Navitron appear to be bigger suppliers than FutureEnergy with whom they do co-operate. I'll keep looking at the boards for a satisfactory solution but may go ahead and start playing myself. I'm currently off-grid but am ready for a new challenge.
Cheers, Jim

[martin]

it does rather beg the question "how come they are twice the price in the UK?" - it seems to me that yet again multinational companies seem to view the UK as a "premium price" market - if an Italian company can flog them for £330 (fellow EU members), why can't British companies?

[Paulh_Boats]

I apologise for muddying the waters a bit, but how will the system work in a gusty situation? I imagine the power varies a lot during gusts which could easily confuse the MPP inverter unless it knew the various time constants of the turbine (like how fast it can speed up/down) and the current wind speed from a small anenometer (just like wind farm turbines).

Also for a given voltage the ideal power to extract will vary with windspeed...so if the GTI does not know the windspeed how does it decide what to do?

It all sounds like great fun if you like tweaking lots of buttons and settings. 

[philipaharris]

My mastervolt inverter was pre-programmed by samrey when I bought their turbine system. The price for the inverter was very reasonable but not as low as £330.
I guess its all down to distribution rights and the strength of the pound.

The programming of the inverter is critical. Get it wrong and you can overload or underload the turbine meaning that it will either stall and not do much, or sit there spinning like hell but not generating much.

I really pleased with my setup and the inverter is a very nice simple piece of kit and a fraction of the cost and hassle of owning a battery system. The only slightly annoying thing is that there is a relay which is constantly clicking on and off when the winds are very low and the turbine is cutting in and out.  Its not so much of a problem as the inverter is hidden away.

Cheers,
Philipaharris

[philipaharris]

Hi Paulhboats,

the mastervolt (and I believe most others) draw power from the turbine based upon the voltage that the inverter 'see's from the turbine. This varies with the windspeed and the speed of the turbine so the inverter doesn't need to know the windspeed. It just applies a preprogrammed load when it senses a given voltage setpoint. I understand that the samrey windmasters have 5 voltage setpoints where as the windyboy inverters only have 2 setpoints. The more setpoints the better as you can more closely follow the turbines true power curve (higher resolution). The power curve will be different for every different brand of turbine depending on the open circuit voltage to rpm ratio of the alternator. Its not really MPPT in the same sense as PV which works on a  slightly different principle.

I've just been offered the chance to test a 16point curve on a new gti.

This is why energy production is better. When charging batteries there is only a constand linear type load which is not intelligent (unless you use 'MPPT' charge controllers with so called 'buck and boost' but these are not particularly good with turbines at the moment). A correctly programmed power curve on a grid-tie inverter can closely follow the power in the wind and make a better conversion of that energy.

Cheers,
Philipaharris

[Ivan]

Hi Phillipa,

Have you measured the standby power consumption (from the mains) of the Mastervolt unit? Does it wait three minutes after wind turbine is up to speed before connecting to the grid? Do you have overvoltage protection circuitry built into the Mastervolt unit, or is a separate unit?

Ivan

[philipaharris]

Hello Ivan,

I haven't been able to measure the exact standby power of the mastervolt as the power meter I use doesn't have a high enough resolution (so it must be less than half a watt). I have tested another gti from holland recently which didn't work particulary well and had a standby power of 1.5watts which was far to much for a 250watt inverter.
The mastervolt does an initial sync when first connected to the mains which takes about 1 minute, but once that is done it responds instantly to the turbine. Its doesn't have to wait around and resync every time the turbine gets up to speed like the windyboy.

The overvoltage protection is built into the samrey power conditioning unit and is not included on the mastervolt. I have been told that the latest power conditioning units have cut-outs which brakes the turbine when the grid goes down and the inverter has to cut out. Another good thing about the samrey system which nobody else offers is the high voltage transmission which means I can put the turbine a mile away from the inverter (or batteries) and still only use small and cheap cable's. The power conditioning box which came with the turbine has a 3-phase transformer which drops it down to traditional low voltage dc, an ammeter and a stop switch! On my other turbine I had to install 25mm cables as the turbine only transmits at 24v and by the time I had bought the cable and switchgear I had spent a lot. My bigger samrey turbine is further away than all of the others and only useds 2.5mm cable (cheap!!!)

Hope this answers your questions.
Philipaharris

[Ivan]

Very helpful.

Yes, under 1/2 watt sounds good - like you, I have seen quite a few inverters that use rather more than that. My 2.5kW SMA units consume around 2-4watts on standby AND they switch off their communication systems so you cannot reprogram them. This would make sense if they were reducing power to an absolute minimum, but that's clearly not the case.

The 3minute wait is a real pain with wind power. I had been told (by SMA rep) that this is part of the G83 standard, so it's interesting that the Mastervolt unit has done away with this. It will certainly improve output.


Ivan