Next morning at 0840 the blades began to turn and generation started. All ran more or less smoothly, although if you stood next to the turbine you could detect a slight clonk as the blades rotated and a groaning noise as the turbine head rotated on the tower. There is also a whistling sound off of a blade due to an imperfection which carries a fair distance, but these are teething troubles and I wasn't overly disappointed.
Generation was in the order of a kilowatt or so every couple of hours, but in the evening the wind got up to 15 knots gusting 25kt, about 7 m/s gusts 13 m/s. I was happy to see 2.5 to 3 kw an hour being made, and my wife and children also enjoyed the novelty of watching the dials move on the rectifier as power was produced.
At about 11 pm my wife was standing watching the dials and the output on the inverter box as the wind was gusting a bit and she was interested to see what the readings were. The inverter disconnected saying something like "PV voltage overload, Disconnect DC."
A few seconds later it reconnected, disconnected again, and a few more seconds later a number of explosions occured in the inverter box. If you have ever seen a steam train blowing off steam, that is the best description of what occured in my hallway. The noise was the same, except there was smoke everywhere, not steam. My wife got one hell of a fright (she was actually shaking with shock for a long time afterwards, and I have to admit,so was I), and ran to get the children out of the house, and I switched off the isolating switches on the control board. She later told me that only my feet were visible through the smoke. We opened all the doors and thanks to the strong breeze the house soon cleared, but we were all extremely shaken by the event. I phoned the owner of the installing company who was also shocked by what had happened. He advised that we stop the turbine as well which we did. After two hours the inverter box was cool and the smell died down enough for us to close the doors, although the windows were left open and we passed a worried night with little sleep.
The next day our installers arrived to take out the inverter and compile a report. They had been away on another island working on another project and had dropped everything to come and do this, which was appreciated. The initial inspection revealed a number of blown capacitors. (I have to say here I have complete faith in the firm that installed my system).
Everyone involved is being extremely helpfull and is taking this very seriously, but our confidence in the safety of the design as it is at present has been considerably dented. If we hadn't been there to switch off, what would have happened? I don't fancy the idea of coming home to a house full of toxic smoke and dead cats, or worse, no house at all. The unexpected happens sometimes and I hope a solution is found to stop a re-occurence.
Total output since installation 21kw, total generating time about 14 hours, then bang! I am sure things will get sorted out eventually but doubts on safety will linger for some time. I will keep you posted on events.
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P J
Proven 6 major inverter failure
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Peter Henderson - 2007-09-07 23:42:58 |
| Re: Proven 6 major inverter failure | Windy Miller - 2007-09-09 16:26:34 |
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Peter
What kind of inverter is it you have? I guess from what you have written it is a single 6 kW? Or have you 2 x 3 kW? SMA or some other make? Have they said what caused this?
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| Re: Proven 6 major inverter failure | Simon Ridout - 2007-09-09 18:04:42 |
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This is similar, but more dramatic than what happened to me at the start of August. I suspect that the inverter had disconnected from the grid, either because of a frequency mismatch or an AC overvoltage, This latter occurs at 260 volts AC. If, like me you have a high grid AC voltage, there is not much of a window between the Grid voltage and 260 volts for the inverter to work within. My Grid volts are 253, the highest legal voltage. United Utilities said that they would 'tap' it down to about 240, within 4-6 weeks on May 24 and I still do not know when they are going to do it, however that is another story, which I will tell one day.
If the inverter disconnects from the mains, the turbine may overvolt, above 600 DC volts, which the inverter does not like. Mine 'poped' one capacitor and I shut it down, without more damage. This was after 6kw of DC radiators (heat sinks) had been fitted as an overvoltage protection device. The inverter is being rebuilt and a better DC overvoltage protector is going to be fitted. The cause of the inverter disconnecting from the grid does not matter, it could had been due to a power cut, which could occur at any time and is most likely to occur if an overhead power line comes down in strong wind, the very time that the turbine is producing maximum power.
The important thing is that these problems are not unique one-offs, they are known to Proven and their distributors/installers and it is up to them to find a way of making safe, efficient installations, every time. So far I have had 10 weeks downtime and 4 weeks running time, since 30 May, mostly due to waiting for spare parts. I am going to insist on the clock for the warranty being reset, to start once the teething problems are sorted. |
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| Re: Proven 6 major inverter failure | Peter Henderson - 2007-09-09 21:54:50 |
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It was a 6kw windy boy inverter. I am surprised to hear that this problem has occurred already, although to a lesser degree, and that no immediate action has been taken on safety grounds.
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| Re: Proven 6 major inverter failure | Ted Marynicz - 2007-09-10 07:55:54 |
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I have 2 x 3kW SMA Windy Boys because my installer was not happy about some of the things he had heard about the 6kW model on the 'grapevine'.
ted |
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| Re: Proven 6 major inverter failure | Stuart - 2007-09-11 10:41:42 |
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Peter
I am really shocked and worried about what happened to you. We do need an explanation about what is going on with these inverters.
Clearly the advice would be not to put one in your home-- |
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| Re: Proven 6 major inverter failure | Peter Henderson - 2007-09-12 13:40:38 |
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I have been in direct touch with Proven and as this appears to be a safety issue to me, I also contacted my local Trading Standards at the council. All parties involved are taking this seriously. If anyone else has had any problems I suggest they do the same. -- P J |
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| Re: Proven 6 major inverter failure | Roger Wetherington - 2007-09-13 17:57:01 |
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Hello all,
My goodness! Is there anyone on here with a turbine which doesnt go on fire, or break down after a few days? In a way, we are glad we found this website, as it really is giving us an insight into small turbine ownership before taking the plunge! However, its not giving us a lot of confidence that a wind turbine is what we should be buying! Peter, I am glad to hear you and your family are alright after this. It sounds like it coud have been much worse. All the reports on here seem to be negative. Is there anyone with any good things to say about small turbines? Its certainly making us rethink our plans on having a wind turbine on the Orkneys. If they only last a few days its not much good! It would be good to hear some positive stories for once, especially from any turbine owners on the Orkneys or the Shetlands, or if anyone knows of any ones there which are succesful. Best wishes
Roger |
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| Re: Proven 6 major inverter failure | Peter Henderson - 2007-09-13 20:52:30 |
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Dear Roger,
I think that the problem is that grid connection is relatively new. In other non-grid applications things seem to run relatively smoothly. Perhaps the answer is to hold back a year or two until solid solutions are found, and people like us have suffered the problems.
His company is Bryan J. Rendall Ltd. |
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| Re: Proven 6 major inverter failure | Roger Wetherington - 2007-09-17 21:22:21 |
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Hello Peter,
Thank you for this information. We gave this chap a call this evening for a general chat. its difficult to know what we will do as we have still not found our ideal place to buy yet so our discussion has been very general so far. But its good to have made contact and find out views of possible turbines we could use on the Orkneys. The view seems to be shared that turbines for places like the Orkneys and the Shetlands need to be very strong and robust! I hear they have been using both Proven and Eoltec for quite a few years now and those are about the only ones they feel are good enough for the gales and sea airs. They say that of the grid connected turbines they have installed in the Orkneys, more have been Eoltec than Proven 6 kw, and that the Eoltec ones have been very reliable and produce a lot of energy. One which they installed 2 weeks ago has apparantly made over 1,000 units of electricity already and they expect them to make over 20,000 units in a year in the Orkneys or Shetlands! We hope to be making a visit sometime soon to look at some properties that are on the market. Its been too expensive to even consider coming to the Orkneys in your tourist season! When we come for a week or so, possibly next month we will have a look around for some of these turbines and hopefully speak to the owners as well as Brian Rendells to find out some more. Thanks again for the information. its been very useful! Best wishes
Roger |
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| Re: Proven 6 major inverter failure | Mick - 2007-09-18 11:23:05 |
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GENERAL COMMENT on the various stories on performance and inverter problems
Since I installed...On June 5th...things are going well ...touch wood
When I hear of these inverter problems ... I am so worried.
To me, as a general comment, I think Proven and there installers...do not know enough or care enough about optimising the connecetion to the grid This is totally ignored by the installers We as a group should share the setting we have on the SMA WB6000...and let’s see the variation.... and try and understand what the variation means in terms of hi winds, low winds, power outs, Hi Grid voltage etc …. And may be some variation is acceptable …but lets understand why I am convinced this is an area that needs more investigation, and more practical research .
When I suggested to my installer that he change the settings in the SMA... the first reaction was ... NO ...but on further pushing and questioning ... he reset certain settings What do u think ?
R
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| Re: Proven 6 major inverter failure | Stuart - 2007-09-18 19:14:32 |
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I am worried to. Why is the inverter not able to cope with the entire output of the turbine, with the grid down. Would this not be the most basic consideration when choosing the inverter turbine combo? -- Stuart |
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| Re: Proven 6 major inverter failure | Peter Henderson - 2007-09-13 20:58:00 |
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Hello again. A positive note on wind turbines. One of my neighbours has a grid connected Proven 2.5 kW turbine and has had no problems in two years of generation. It is so good that he says forgets all about it other than when it needs serviced, and the meter needs to be read. -- P J |
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| Re: Proven 6 major inverter failure | Bryan Rendall - 2007-09-24 13:46:58 |
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Hello to everyone.
My name is Bryan Rendall, director of Bryan J Rendall (Electrical) Ltd, the company in Orkney who installed Pete Henderson and family's turbine system. I see that this incident has understandably generated a lot of interest and following investigations, we have some information that will help set the record straight on exactly what happened. We have identified an assembly error in Mr Hendersons turbine, whereby our technicians who installed the turbine, made an error in fitting the wedges which interface the blades to the hub. The result of this error was that the blade pitch was wrong, and caused the turbine to run much faster than it should have. This higher RPM generated a significant overvoltage, compared to the design voltage, and accordingly caused 3 capacitors in the SMA inverter to fail. The effects of this failure is well documented in Peters post above. As soon as we became aware of the problem with Mr Hendersons turbine, we attended to his property and removed the inverter for further examination. That, along with input from Proven Energy Ltd. pointed to a blade fitment problem, which was confirmed last week. We have installed many turbines all over Scotland, including quite a number of grid connected Proven 6 kW ones, and it was very concerning to us that our installation procedures allowed this error to occur. We have modified these procedures accordingly to ensure that such as mistake does not happen again. We are also liaising closely with both Mr Henderson, and Proven Energy Ltd, to ensure that we can all reach a satisfactory conclusion. There are a few points I must emphasise though. 1. The failure of Mr Hendersons inverter is an isolated incident which arose from incorrect turbine assembly on site. This led to a massive overvoltage and failure on the DC bus capacitors. 2. This overvoltage incident is completely unrelated to any other overvoltaging that may be experienced on turbines which have been assembled correctly, in certain high wind conditions, if the turbine is unloaded. This may result in a mild overvoltage, with marginally over 600 volts produced on the output of the turbine controller. To date, we have not experienced any lasting over-voltage problems in grid connected turbines, when the turbine is installed fully in accordance with Proven instructions. 3. We are very concerned that this incident occurred, when we have procudures to make sure turbines are correctly installed and commisioned. Procedures have been modified to ensure a re-occurance is avoided. 4. We are very sorry for the concern which has been generated within the Proven Owners Community. We are also very sorry for the distress which Mr Henderson and his family suffered at the time of the incident, as well as any less than favourable reflection this incident has had on Proven turbines. To both the Hendersons and Proven Energy Ltd, we apologise for this. Aside from this posting, we will be communicating the findings of the investigation to all concerned, including Trading Standards. Yours sincerely Bryan Rendall Director
Bryan J Rendall (Electrical) Ltd.
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| Re: Proven 6 major inverter failure | muymalestado - 2007-09-24 15:24:42 |
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Mr Rendall's response confirms that there are still commercial operators out there who have integrity. -- muymalestado |
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| Re: Proven 6 major inverter failure | Mick - 2007-09-25 12:45:07 |
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Mr Rendall Your response is clear and understood I applaud you and your company for your honesty and clarity The Explanation certainly helps R
M |
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