Where to add SPD's

[asdex]

Hi, have finally finished my layout design that I'm happy with. Could some one give me advice on where to put SPD's needed. I know on the 230v output from the inverter is most important but expect I need to protect the Midnite Classic as well.
Thanks,

[mike90045]

I'd put one at the combiner box (not shown on your dwg) before the PV wires get to the controller.

You most likely need a combiner box at the PV array

Another one on the AC output of the inverter(s).

If you get a direct strike, it's all over anyway.  Batteries will be all that's left.   Where did you find 500ah-3V batteries ?

[asdex]

Ok thanks for that. What about the wind generator? Does it need one to protect the three phase rectifier?
The batteries are a representation of a gereric bank. At the moment I have 8x 6 volt 220AH batteries which I will series/parallel up into a 24 volt bank. They are getting to the end of their life but I have some 100AH 6 volt AGM batteries coming from work ex a UPS. About 70 of these but I'll grab enought to make a 500ah 24 volt bank. They are three years into a 12 year lift span.
Cheers,

[mike90045]

Ok thanks for that. What about the wind generator? Does it need one to protect the three phase rectifier?......

I'd not bother, unless it's really hard to get to the $15 diode pack to replace it.   Diodes up high on a wind turb should be several hundred volt spec anyway.   Protect a $15 part with a $90 gadget ? And you would need at least 2 for a 3phase turb.  But the controller should be protected with one

[asdex]

Ok thanks, that sounds good. The wind generator rectifier is at ground level so easy to replace. I'll get two SPD's. I'll put one at the combiner box which is at the PV's and one on the inverter output. The PV panels are about 20 meters from the controller and the cable is underground. Should I put on near the controller input too?

[mike90045]

you need a SPD at the input of each wind controller too.  So if there is some induced voltage from a strike, the controller is not fried. 

I guess you should think over the diode failure scenario too, if the diodes fail, how do you brake the wind turb ?   Or just oversize the diodes so they don't fail ?

If the PV SPD is at the combiner box, and grounded there (a ground at the PV) so that a stroke is diverted and not channeled into your power shed to find a ground there.  Your underground wires should be safe enough for that distance.

But remember, a direct strike, and all that stuff is vaporized. Sometimes even the ground wire!  You just do the best and home for a miss.

[dgd]

I can't remember the SOMA 1kw outputs but if the rectifier is at ground level then its probably 3 phase AC output to a 3phase rectifier to produce DC output.
There was some discussion here about MN having or developing a 3 phase SPD, that would be the one to put between SOMA and rectifier.

dgd

[asdex]

Thanks, yes the Soma is three phase to a bridge rectifier. I have no wind turbine controller and will connect the output directly onto the battery bank as in the diagram.
Cheers,