[RFI] Power Line Noise in Indonesia
Phil Duff NA4M
na4m at arrl.net
Mon Jul 19 12:26:43 EDT 2004
At 14:52 7/19/2004, Chuck O'Neal wrote:
>In my years of locating and having the local, very cooperative, power
>company repair line noises, we have found that the vast majority of
>radiated line noise is due to bad splices, connections and tie wires, not
>insulators. The characteristic of a noisy connection is that it goes away
>during rain. The few insulator problems seen were worsened during rain.
A year or so ago I had our local community owned utility guys out to fix a
problem I had tracked down to a pole or poles across the street.
Interestingly during their visit my conversation with the crew foreman on
the ground directing the guy in the bucket revealed that many problems are
caused by induced voltages in hardware that is not attached to the hot wire(s).
That was one problem on the pole they fixed. They had to attach a ground
wire to a pole hardware bracket that was hot and arcing from induced
voltage from the hot line even though the bracket was some feet away from
the hot wire.
The utility had recently upgraded the system from 7200 to 14400
volts. This in turn had exacerbated the induced voltage problem on this
particular pole. I found it interesting that hardware in some cases
several feet away from the hot line(s) could create arcing/etc. from
induced voltages. The foreman told of linemen being shocked and knocked
down by these inducted voltages.
73 Phil NA4M
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