Four months later we had a new turbine and new blades and for just over a year things were fine. We generated about 8000KWH during that time, which, while less than the sales pitch, was perfectly acceptable. We had an independent installer round for servicing and he advised that he would be surprised if we got less than 10000KWH per year, so our site location is clearly not bad.
Then in July 2008 we had a major electrical failure. This turned out to be a known overvoltage issue. Four months later all the electrics were replaced along with 3KW heat dumps to prevent overvoltage in the future. We had two 2.8KW inverters on loan as a 6KW unit was not available. Over the next 12 months we generated only 4000KWH. This was obviously a disappointment and I was advised by Proven that the two smaller units would be less efficient and hence my lower generation.
Eventually, we managed to get a replacement 6KW inverter and after many replacement chips and reprogrammings of said chips, we appeared to have a working system again with all the overvoltage protection built in! I couldn't be happier. Seven months on and we appear to be heading towards an annual generation of between 2500 and 3000KWH!!
So each time Proven 'fix' my system my output is approximately halving. Is it possible that the wind speed in the UK has been dropping off for the last four years or is there likely to be a software solution? I understand that my new 6KW inverter has the latest 7 phase curve in its software which should be more efficient but even on very windy days it is often generationg just a few hundred watts and also sometimes disconnects and appears to be unable to reconnect due to the very high voltages.
The annoying thing is that our all-electric house uses about 10000KWH per year and we should be generating pretty much all our own requirements.
|Where's the wind gone?||Geoff Forwood - 2011-01-10 22:03:28|
|Re: Where's the wind gone?||blo - 2011-01-12 16:22:22|
Could it be the blade springs are getting weaker and needing replacing.
Our local installer has to replace the springs frequently on the Provens in this quite windy area. He says it reduces the power if they are weakened but I would have thought it was more than weak springs with yours. He showed me a set of springs. Some were stretched and some were broken, one had broken and gone flying. It seems they have to be replaced for safety as well as for low power.
Unfortunately they are quite pricey too.
|Re: Where's the wind gone?||Peter Benning - 2011-01-12 21:03:16|
Yes, the wind has definitely dropped over the last 2 years - which is why we have had such cold and snowy winters! The jet stream which normally provides us with relatively warm westerly winds - (good for our wind turbines) - has moved to drag in cold northerly winds. This with high pressure sytems, has seen a marked reduction in the output of our Proven 6kW Turbine.
Our first year (Jul 07 to Jul 08) produced 17.25mWh's; 08 to 09 15.25mWh's. This calendar year - 2010 produced only 10.2mWh's.
We have had similar problems to yourself. First a yaw bearing bolt sheared; this did not cause too much of a problem, and I just replaced the bolt. I contacted Proven, and they said the blades maybe out of balance, and sent me a new set! These were supposed to be more efficient, which may have lead to the same problem you had - DC overvoltage. The Windy Boy can cope with up to 500vdc, by dragging down the amperage to limit output to 6kW. However in these strong winds, you often get blips in the grid supply (lights flickering). The Windy Boy senses this as a grid failure (0.2 of a second) and disconnects from the grid. This sends the dc voltage way above the 500v - (turbine unloaded). The Windy Boy will now not reconnect to the grid till the wind drops - which can be several hours. Proven's solution was a modified Control Box (rectifier) and 3 x 1kW heaters (1 for each phase) to load up the turbine to help reduce the dc voltage. A relay closes at about 450v and the heaters come on. Output can now be up to 9kW's.
Our Windy Boy failed during a bad storm, with "K1 relay open". We had a new one fitted, and like yours, supposedly more efficient...
Interesting about the blade springs. I do my own servicing and our springs appear ok, just the spacers wearing; but I will check more carefully this next annual service. If you look at pictures of the new Proven 11 (6kw!!) it has what looks like just 3 hydraulic rams instead of 3 sets of springs...
Finally, today, have just past 50mWh's
|Re: Where's the wind gone?||Quentin Gargan - 2011-01-16 20:11:22|
The wind may have declined, but not by as much as you seem to be suffering.
I reckon the most likely problem is that your new inverter didn't have the proper power curve programmed into it.
This is a simple procedure, and some inverters (such as Aurora for example) can be plugged into a USB port using software off their site.
Proven should be able to give you the proper power curve for your machine.
Good luck with that - its worth fixing. Quentin.
|Re: Where's the wind gone?||scott smith - 2011-01-21 18:08:00|
have you counted the number of springs left on each blade?
they often break and come of and then the output is low
i have heard of some 6 kw turbines that have been found with less than half the number of springs on each blade as their should b
|Re: Where's the wind gone?||Quentin Gargan - 2011-01-21 21:44:46|
Scott's post reminded me of a 6kw machine near here on which one of the slip rings failed, so it was only running on two phases (i.e. one phase). This had dramatically reduced output.
The brake rope had somehow got caught around the slip ring. Might be worth checking... Q