[UK-CONTEST] Power Line Noise

[Adrian Rees (MW1LCR)]

OT but maybe of interest....

We had a Power Outage starting Monday night with no Power being restored
until this morning.

This was caused by a faulty 11Kv line coming up the hill to my QTH. This
line branches off about 500 yards away from my property. The fault was
at this branch location.

Prior to the outage, around Christmas time,  I first noticed noise,
typically S 8 - 9 between 3 and 9 MHz. Doing the usual switch everything
off and isolate the source routine, I couldn't identify its source. The
noise continued, irrespective what time of Day or Night I checked. I
even went as far as switching the mains off to the house, and running
the rig off batteries. To no avail ! I concluded that it must either
have been coming from our nearest neighbours (about 50 yards away) or
from something or someone else. The neighbours kindly co-operated one
afternoon, and switched off their supply for a few minutes. The noise
was still present. I also tried different rigs...again to no avail.

Last night, whilst we still had no power, I tried  the rig on
batteries...no noise.  

The on site manager who was leading the fault team, came up to my house
to check the power etc, and noticed the Royal Signals Plaque on the
wall. Turns out he is ex REME. Anyway, I mentioned about the radio
noise, and its sudden disappearence. Apparently, some Power Companies
are using an "Active Monitoring" system, which enables them to detect a
break or failure in 11Kv Power Lines from various control centres. He
explained that as well as fixing the broken cable, he also had to fit a
new monitoring sensor to two 11Kv Transformers. These sensors detect
failure in the cables, and report the failure, electronically to the
control centre. According to him, Manweb / Scottish Power are fitting
these to remote locations, as an aide to detecting faulty conditions.
The ones he replaced were also faulty. He showed me one, and they are
made by EA Technology. 

So I suppose that we have gotten rid of BPL, but the power companies are
using something similar as an aide to fault diagnosis.

All has been restored, and noise on 7MHz is just Italian, again !

73

Adrian
MW1LCR

 


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