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Forum Index : Windmills : Over voltage protection on my Turbine
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| smithy Regular Member  Joined: 30/01/2011 Location: AustraliaPosts: 52 |
I am looking into the possibility of using TVS (Clamping) Diode as an overvoltage protection mechanism for the odd occasion that my Wind Turbine generates high voltages during storms. Is this a common practice as it looks like from the specs that if you choose the correct one it clamps the upper voltages. I don't really want to cook the Grid Tie Inverter (one of the ones from China) by accidentally having the voltage go over the capacity of the inverter. The idea is that I take the 3 phase AC from my wind turbine and put it through the bridge rectifier and then have a TVS "Clamping" Diode prior to the DC voltage going into the Grid tie inverter (does the effect of the diode actually clamp the voltage or does it short the voltage, as I don't want to cause it to cook the GTI) Smithy "The answer my friend is blowing in the wind, the answer is blowing in the wind" Bob Dylan |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
I knew the answer but just to be sure I looked it up as well : answer Just make sure its sufficiently rated to dissipate the power. Klaus |
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| SnowGhost Newbie  Joined: 09/09/2010 Location: AustraliaPosts: 16 |
You can also use one of these. Rob beckers over at www.greenpowertalk.org has a wireing diagram to send the power to your dump load, which uses the omron relay |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Smithy The dump load controller Glenn designed in the projects on the home page is really good a simple. All the best Bob Foolin Around |
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| smithy Regular Member Joined: 30/01/2011 Location: AustraliaPosts: 52 |
Bob, Is the following like the "dump load controller" you were refering to. Link to Dump Load Controller. Since I wasn't going to be linking to a battery I was thinking of using the 1 diode approach (KISS Principle), but accept that its unlikely to be as simple as I would like it to be, and certainly an upper cut out, and lower cut out voltage limited device is preferable for Battery systems. Smithy "The answer my friend is blowing in the wind, the answer is blowing in the wind" Bob Dylan |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Smithy Yep that's it. Unless you have a load on the generator the voltage will fluctuate wildly and from sad experience I can tell you it will cook, or blow the input caps, one of the main problems is when it starts up it takes a few seconds to lock onto the grid at this time it draws a small current but not enough to load the generator and volts will go way to high, if you are lucky it will shut down on over voltage but most likely it will exceed the safe max input voltage and create magic smoke. I do not believe the diodes you are looking at could dissipate the power required to control the voltage and it would be something else to blow before it blows the Inverter. The load controller could put a partial load on the generator into a dummy load RESISTIVE not a politician, but allow enough power to remain to sync the Inverter and then it would draw power and drop the volts. \\As a wind turbine works over a lot of different speeds it is nearly impossible to work into a non MPPT cheap Inverter. All the best Bob Foolin Around |
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| smithy Regular Member Joined: 30/01/2011 Location: AustraliaPosts: 52 |
The TVS clamping diode appears to be built for instantaneous voltage spikes and won't last for a prolonged period (i.e minutes). One query I have about Glenn's Voltage controller is that I am trying to figure out if when the relay (for over voltage) kicks in, does it then isolate the battery and push all the charge to the dump load. If so, this is not quite what I was after as I really wanted to feed the output into a GTI (instead of a battery) with any extra over voltage taken up by a dummy load, whereas I think Glenns controller redirects the entire load to the dummy. Smithy "The answer my friend is blowing in the wind, the answer is blowing in the wind" Bob Dylan |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Smithy, the way I understand it you can't have a dummy load and a battery in parallel at any time as the dummy load would flatten the battery. What you need to do is power the GTI from the battery (bank) and charge the battery from your wind turbine via the voltage controller. That way your GTI always sees the battery voltage and never an over voltage. If you are worried this may flatten the battery when the wind stops adjust the low voltage cutout of the GTI to separate the two before the battery gets discharged too low. Klaus |
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| smithy Regular Member Joined: 30/01/2011 Location: AustraliaPosts: 52 |
Thanks Klaus, Certainly probably the easiest way of going instead of trying to fir a square peg into a round hole. Pete "The answer my friend is blowing in the wind, the answer is blowing in the wind" Bob Dylan |
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KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
I use the battery idea works a treat and tough to beat! certainly 100% reliable with 2 separate dump load circuits on the PL20 should the grid go down. 1st one is PWM controlled 2nd is the jezus dump which is 3000W or so, theory there is should the first home made dump load blow up it has four more in parallel controlled by a solid state relay, voltage hits 60V, something has gone wrong and the heaters light up, dropping the voltage down to 56V before it un-latches again. Luck favours the well prepared |
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