Smart
Grids a potential new vehicle for rural and urban LFN nuisance (or the Hum) and
its acoustic component, is there a simple way Smart Grids could be
inadvertently maximising this human inconvenience? By Dr Chris Barnes, Bangor
Scientific and Educational Consultants, e-mail doctor.barnes@yahoo.co.uk
Abstract
The Hum is defined and
its history is discussed. A brand new and simple hypothesis is advanced for the
increasing prevalence of LFN/ the Hum in terms of the operational behaviour of
pre-existing domestic, commercial and industrial noise and vibration sources at
night changing from the previously random
to the precisely controlled under the influence of Smart Power Grids.
Introduction
The Hum is a geo-sporadic noise nuisance
heard/perceived by an estimated 2% of the world’s population, this figure
probably rises to well over 10% in the 40-70 age groups. The noise, an irregular pulsation like very
low pitched buzz, can be extremely irritating and annoying and in its extreme
even cause stress related illness and sleep deprivation. It is mainly but not exclusively in buildings at night even with the power switched off
and is characterised by the sound of a
slowly and irregularly (quasi –periodically) idling engine and these days is
perceived by the present author as often more sharply pulsing than
musical. Those musically minded hearers
of the first instance of the Hum in the USA, the so called Taos Hum toned matched
it between 30-80Hz and stated that it has quasi-period modulations or
fluctuations of between 0.5 and 5Hz.
Others describe a higher pitched buzzing yet still with the same sort of
underlying modulation. Another
strange facet of the Hum is that is either difficult or impossible to audio
record, this has been particularly so in the past before the advent of readily
available FFT systems. Sadly this has
pushed the Hum, for some, into the realms of Science Fantasy. This paper, as
with the other works of the present author, aims to demystify the
phenomenon.
Everything but power systems has
officially been blamed for the Hum. Scientists at Southampton University
concluded it is simply distant noise.
Wikipedia blames amongst other things colliding waves under the
ocean. Applying critical thinking one
immediately wonders why then distance noise or ocean waves shouldn’t cause the
Hum in the bulk of Russia and Africa and other places which either don’t or
until recently haven’t experienced the Hum.
Contrasting all kinds of infrastructure
between places that don’t and do experience the Hum and using world mapping it
has recently been shown that the Hum is best correlated with sites wherein
there is connection of renewable energy to the power grid. Another common denominator with power grids
which use a considerable proportion of renewable energy is that they tend to be
so called Smart Grids. Smart Grids tend
to control their power flows, amplitude and frequency by means of communication
networks running as part of the Grid itself or in parallel such as radio links
or optical fibre links. Long time
amateur Hum investigator John Dawes has suggested power systems may be to blame
since the first Bristol and Largs Hums in the UK in
the late 1970’s and early 1980’s but has never been able to be specific about
which elements of such systems were the cause, instead John has referred to the
general upgrading of the grid which took place in that era. John does however have quite a controversial
theory of how the Hum might be perceived in terms of gravity modulation. The present author can see at least three
physical mechanisms as to how this can occur but not everyone might understand
or agree. All of these mechanisms will also modulate air pressure to a greater
or lesser extent and some have made observations on the Hum in respect of
barometric changes. It is imagined
that John came up with his hypothesis to account for lack of audio recordings and to explain how some deaf people claim to hear the Hum
(and presumably describe the same noise as hearing people) and as to accounting
for how the Hum is sometimes difficult to screen with ear plugs.
The present author has previously
explained the more complex facets of the Hum an in particular how some people
can perceive the Hum in unlikely places and how deaf people might be able to
perceive the Hum. These types of
perception require a magneto-acoustic hypothesis of both Hum generation and
perception [1] or the former
hypothesis of perception and an alternative method of perception involving
gravitation [2, 3].
However the question now posed is can
Smart Grids, in conjunction with renewable energy account for the recent
World-wide explosion in cases of LFN/the Hum?
Not discounting previous valid hypotheses of the Hum, particularly as in
its relation to ground currents and dirty electricity (Havas and Stetzer 2004) which has recently been independently
asserted by some Canadian researchers [4],
can there be a simpler purely acoustic cause of the Hum arising from every day
domestic and commercial sources controlled by smart grids? It is certainly known that such sources can
contribute to Hums, take Kokomo for example, see Cowan (2008) [5].
Yet to date domestic, commercial and industrial sources of the Hum have
been the exception rather the
rule. Until very recently indeed, there
have been no significant cases of the Hum in Russia or China. The author feels this is likely to change
more as both countries invest in Smart Grid Technology and possible change from TT to PME electrical earthing
systems.
How
Smart Grids can change the operation of mundane every day noise and vibration
sources for the Hum.
Taking the behaviour of the UK Power Grid
as an example is particularly instructive. The present author has already
pointed out how smart grids and renewable energy contribute to power flow
oscillations and harmonics and how these can impact on both noise from
generation in the rocks and soil directly under buildings experiencing the Hum [6].
It is also described in the literature how banks of capacitors
particularly associated with industrial electricity supply can vibrate and be a
source of LFN.
But what of more mundane and pre-existing
potential noise and vibration sources such as domestic, commercial and
industrial refrigerators, fans, heating systems and compressors? Noise from these types of sources can enter
premises by both airborne and ground borne pathways and conduct through walls
of attached houses. Prior to the advent
of smart grids the operation of such noises would have been almost completely
random.
Nowadays in the UK and the USA http://best.berkeley.edu/~aagogino/Slides/JMathieu_BestTalk_4.4.12.pdf [7]
this is no longer the case. Huge blocks of such devices across swathes of
the country will turn on and off as required
for frequency control (load bolstering or shedding) and reactive compensation all controlled by the smart grid
either by frequency or wave shape sensitive internal circuitry or by radio
tele-switching . Tests on Smart
Freezers have been going on since 2009 [8]. http://www.greenwisebusiness.co.uk/news/europes-largest-smart-grid-trial-to-be-tested-on-fridge-freezers-843.aspx Such devices will radiate acoustic and seismic signals (if floor or wall
mounted) at mains synchronous fundamental
frequencies, harmonic and sub –harmonic frequencies and at their own mechanical resonant
frequencies, in other words a formula for the Hum. These noises will also fluctuate in amplitude
and frequency according to national and local power flow oscillations to
boot. In other words we have new and
substantial families of coherent night noise sources throughout the country or
a particular neighbourhood which previously only behaved randomly. Variations
in their propagation paths will be sufficient to introduce the
quasi-periodicity of the Hum.
Quasi-periodic air pressure oscillations which are a natural phenomenon,
, see Delyukov
and Didyk (1999) [9]
, could also potentially influence Hum
propagation but are not in themselves the source, thus this new and simple
theory for the acoustic component of the Hum and its ever increasing prevalence
also fits well with the author’ previous observations of the Hum as a
phenomenon with both an anthropogenic and a natural component [10].
According to the present hypothesis, noises generated by Smart Grid controlled
devices can propagate several kilometres at night. However, unless the power to entire areas could
be switched of it might be difficult to prove this very plausible hypothesis of
the Hum. The Hum in the Bangor area is not such a problem in
the day time because in the UK, Dinorwig pumped storage hydropower station is used for
frequency control instead. The Hum is
not always heard in big cities where there is continuous vehicular movement as
this destroys any coherence in its ground borne components.
It is not proposed that this present hypothesis explains all cases of the Hum, but could well help account for its recent
prevalence in the 21st Century context in the UK and USA in
particular.
Conclusions
In addition to ground induced vibration
through currents of ‘dirty electricity’ and vibration of capacitor banks at
sub-stations, Smart Grids have here been shown to be a potential new source of
wide area LFN having the tonal and quasi-periodic properties of the Hum through
the acoustic and seismic emissions of commercial and household devices they now
regularly and mainly nocturnally control to achieve frequency and load
management. In the UK such devices are
more likely to be used for such control at night-time as Dinorwig
pumped storage plant is exclusively used for this purpose by day. Not all cases of the Hum will be due to
this source of LFN but the hypothesis ought to provide a reconciling factor for
those who can either accept or comprehend no other means of causality. Certainly the increasing prevalence of LFN/
the Hum can now also be accounted for in terms of the operational behaviour of
pre-existing domestic, commercial and industrial noise and vibration sources at
night changing from the previously random
to the precisely controlled under the influence of Smart Power Grids. This hypothesis does not detract from any of
the other work of the present author and can work in parallel with the
magneto-acoustic or gravito-acoustic generation and detection of the Hum, see Barnes [11].
I have commented in the past on the Hum and Earthquake
connection, see Barnes 2012 [12]. In the field of earthquake science new types of sensor have recently been developed
which
exploits changes in the propagation of background ‘underground hum in the frequency
range 16-2000 Hz. There is independent confirmation
of the type effects I have observed by
human sensitivity alone to be at http://earthsciences.typepad.com/files/acous1_05en-1.pdf Belyakov 2005 [13].
Acknowledgements
The author wishes to acknowledge his wife
and son for valuable discussions of the Hum and further to acknowledge emailed
anecdotal evidence sent directly to him from various UK sufferers of the Hum.
References
1. http://www.drchrisbarnes.co.uk/HUMUNIFY.htm
2. http://www.drchrisbarnes.co.uk/HUM3FIELD.htm
3. http://johndawes.pwp.blueyonder.co.uk/living.htm
4. http://emfandhealth.com/HavasStetzerWHODirtyElectricityStudies.pdf
5. http://www.icben.org/2008/PDFs/Cowan.pdf
6. http://www.drchrisbarnes.co.uk/lfnhum.htm
7. http://best.berkeley.edu/~aagogino/Slides/JMathieu_BestTalk_4.4.12.pdf
9. http://link.springer.com/article/10.1007/s004840050113#page-1
10. http://www.drchrisbarnes.co.uk/HUMCAVE.htm
11. http://www.drchrisbarnes.co.uk/HUMSPECIALNOISE.htm
12. http://www.drchrisbarnes.co.uk/HUMEQ2.htm
13. http://earthsciences.typepad.com/files/acous1_05en-1.pdf Belyakov