Re: [TenTec] Latest BPL events...

[Jason Buchanan <jsb@digistar.com>]

Ken Brown wrote:

> Using unbalanced HV (or medium voltage) power distribution seems to be a 
> new thing here in the USA. I have been looking at power lines as long as 
> I can remember, and the use of one hot lead and one grounded lead for 
> the distribution on the primary side of the pole pig transformers is 
> something I have only seen in the last several years. 

I see the same thing here where I live in one of the Boston suburbs. 
There is a single HV line along the poles here and a smaller ground 
wire.  That's it - I always thought there had to be one voltage line for 
each phase.  Looking at the pole pigs there is a 75 stamped on the side 
which I guess means the distribution line is 7500 volts.  How the heck 
are they doing this?  Some form of QAM? :-)

So for 220VAC applications, how does this work?  Do you know of any 
links that discuss this and the performance implications?

The AC service I have is not the same as I am accustomed to.  There are 
quick 1/10th second moments where the lights in the house are a bit 
brighter, other times the line voltage sags to about 110V or goes as 
high as 122VAC.


Also, I notice that the local electric company uses some kind of 
broadband signalling across the line because occasionally a burst of S9 
packet-ish noise lasts for about a half second - on MixW it appears very 
clearly as a bunch of carriers.  When I am running 100W I notice 
sometimes it must interfere with their signalling because it has to 
retry a few times.


regards,
Jason W0JSB


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