Topband: Wind Farming

[Jim Brown]

Brian,

The last paragraph is particularly interesting. Variable speed drive 
motor controllers are well known noise generators, primarily because 
they are generally very poorly installed in a manner that their wiring 
forms loops with a large loop area, establishing strong magnetic fields 
that strongly couple harmonics of the square waves used to control the 
motors.  The fix is to reduce the size of the current loop.

It would be interesting to know if any of this might be part of the 
problem at the wind farm near ZL6QH.  I'm forwarding this email to the 
RFI reflector.

73, Jim K9YC

On Fri,4/1/2016 5:22 AM, Brian Miller wrote:
> Thanks Frank
>
> I was previously the chair of the Quartz Hill User Group responsible for the ZL6QH station.
>
> We undertook measurements of the noise from the wind farm at the ZL6QH site. A report on our measurements is published at http://www.zl6qh.com/rf-noise-measurements-quartz-hill-2009-v3.pdf .
>
> The ZL6QH wind farm used Siemens 2.3 MW variable speed turbines. We  believe the noise was generated by the water cooled electronic power converter technology that was used to convert the variable output of each turbine to the fixed voltage and frequency of the national grid.
>
> Our observations suggested that a HF contest station would have be located at least several km from a wind farm using these turbines to reduce the interference to an acceptable level on the low frequency bands.
>
> But not all turbines are this noisy. We also conducted some HF radio frequency noise measurements at the Meridian Energy Te Apiti wind farm (near Palmerston North) in October 2005 but found no evidence of any significant noise being radiated by the turbines, even at locations within 100 metres of the nearest turbines. Unlike the turbines at Quartz Hill, the Te Apiti turbines were a fixed speed design and did not use a separate power converter unit
>
> 73
>
> Brian VK3MI ZL1AZE
>
> ------------------------------
>
> Message: 7
> Date: Wed, 30 Mar 2016 15:59:34 -0400 (EDT)
> From: donovanf at starpower.net
> To: TopBand List <topband at contesting.com>
> Subject: Re: Topband: Wind Farming
> Message-ID:
> <990159030.6273859.1459367974629.JavaMail.root at starpower.net>
> Content-Type: text/plain; charset=utf-8
>
> The Quartz Hill Contesters -- once very well known as ZL6QH --
> were forced to shut down their spectacular contesting location
> by the RFI from a wind farm installed in the same location as
> their contest station.
>
>
> http://zl6qh.com/logs/Quartz%20Hill%20Pictures%20-%20%20March%202010.pdf
>
>
> 73
> Frank
> W3LPL
>
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