Electric and magnetic fields – April 2013 Homebush to Rozelle cable project

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18 Οκτ 2013 (πριν από 4 χρόνια και 8 μήνες)

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Electric and magnetic fields – April 2013
Homebush to Rozelle cable project
During Ausgrid’s community consultation for the Homebush
to Rozelle 132,000 volt cable project, there has been
particular interest from residents of Charles and Elswick
Streets in Leichhardt about electric and magnetic fields or
EMF in relation to the revised route through the Leichhardt
and Lilyfield areas proposed earlier this year.
Ausgrid has modelled the magnetic fields that would
be found around the proposed cables once they were in
service (as electric fields are readily shielded they were not
modelled). This modelling assists us with route planning and
in providing information to the community.
In addition to Ausgrid’s modelling, we recently
commissioned independent modelling of magnetic fields as
part of preparing the project’s environmental assessment.
Ausgrid has now received the independent magnetic
field report which is available to the community and is
summarised in this sheet.
Independent report
Magshield Products has completed a magnetic field
assessment for the operation of the proposed future cables.
This modelling was prepared using typical daily maximum
electrical load under future loading conditions, as
recommended by the Energy Networks Association. The
maximum loading is not associated with a particular year as
the lifespan of the cable at 45 years is much greater than our
forecast window of 20 years.
The report by Magshield has confirmed that there will be
little, if any, change to the levels of magnetic fields found in
properties along the cable route.
Magshield’s report found that the calculated magnetic
fields at eight metres or more “would be well below the
values that can be commonly measured in suburban streets
containing low voltage power lines that supply electricity to
residential properties”.
Please see table (bottom right) that shows the modelling
of magnetic fields for the proposed cables from the
independent report (Magshield) and from Ausgrid’s report.
For the complete independent EMF report, please visit the
project web page or contact us directly (details overleaf) and
we can send you a copy.
Predicted EMF modelling for cables between Leichhardt to Rozelle (9P9)
The graph above taken from the independent report shows
the predicted magnetic fields from the section of the
proposed cables between Leichhardt and Rozelle (9P9). The
cables would be arranged in trefoil (triangular formation) in
most instances.
Predicted magnetic fields
Homebush to Croydon (9P2) cables
0 metres 5 metres 10 metres
Magshield 76.5mG 11.0mG 3.1mG
Ausgrid 74mG 10.4mG 2.9mG
Croydon to Leichhardt (9P8) cables
0 metres 5 metres 10 metres
Magshield 36.0mG 5.2mG 1.5mG
Ausgrid 34.8mG 4.9mG 1.4mG
Leichhardt to Rozelle (9P9) cables
0 metres 5 metres 10 metres
Magshield 16.5mG 2.4mg 0.7mG
Ausgrid 16mG 2.3mG 0.6mG
Modelling is assuming measurements from 1 metre above
ground in the trefoil cable arrangement at maximum
Planning the route
Safety is Ausgrid’s highest priority. In planning a project such
as the Homebush to Rozelle cable project, we take seriously
the need to ensure the safe installation and operation of our
cables for the community and Ausgrid staff.
While there are many 132,000 volt cables laid in residential
streets across Sydney, they generally are in service for
30-40 years so there are not often projects of this type in
a particular area. The cables we are replacing between
Homebush and Rozelle have been in service for more than
45 years.
Ausgrid recognises that a major and unfamiliar type of
project such as this can cause concern for local communities
and that it is necessary to provide as much information as
possible to help address your questions.
What is EMF?
Electrical energy involves ‘voltage’, which is the pressure
behind the flow of electricity that produces an electric field,
and ‘current’ is the quantity of electricity flowing that
produces a magnetic field.
Electric fields are naturally occurring and can be present
in any appliance plugged into a power point and
switched ‘on’.
Magnetic fields are only present when electric current is
flowing. The strength of a magnetic field depends on the size
of the current. Like electric fields, the strength of magnetic
fields drops off quickly as you move away from the source.
Magnetic fields and this project
The magnetic fields from the proposed 132,000 volt cables
would comply with the relevant Australian health guidelines
and would cause little, if any, change to the magnetic fields
at any properties along the route.
In built up areas there are existing background levels
of magnetic fields including those from household wiring and
appliances, that may contribute more to everyday magnetic
field levels than public electrical infrastructure in the street.
Ausgrid is guided by Australian Government agency
ARPANSA. ARPANSA states that typical levels in locations
away from electric appliances are approximately 0.1 -2 mG.
What is prudent avoidance?
Prudent avoidance is minimising electric and magnetic field
exposure provided this can be readily achieved without
undue inconvenience and at reasonable expense.
In the case of the proposed Homebush to Rozelle cable
project, this includes selecting streets, where feasible, that
are wide enough to allow magnetic fields to drop over
distance from adjoining properties.
Magnetic fields can also be reduced by arranging the three
phases of the circuit in ‘trefoil’. Trefoil arrangement, when
compared to a flat arrangement ‘localises’ the magnetic
fields due to the closer separation of the phases. Trefoil
phase arrangement would be utilised in most instances along
the proposed cable route.
Where can I get more information
about EMF?
Further information about EMF is available from:
Ausgrid at www.ausgrid.com.au/emf
ARPANSA at www.arpansa.gov.au
Energy Networks Association (ENA) at www.ena.asn.au
World Health Organization (WHO) at
Contacting us
You are welcome to contact us with any enquiries:
T 1800 214 193 (free call from fixed phones)
E majorprojects@ausgrid.com.au
W www.ausgrid.com.au/homebushtorozelle
Ausgrid’s approach to EMF
While there remains a lack of scientific consensus
about whether magnetic fields can cause any adverse
health effects, Ausgrid understands that there is
concern in the community about electric and magnetic
fields around high voltage cables. We take seriously
our responsibility to help address these concerns by
providing balanced and accurate information about
EMF, by taking reasonable steps to limit exposure and
by operating all our electrical installations prudently
within Australian health guidelines. We also monitor
research and policy into magnetic fields and health.
As there is a lot of research and studies regarding
health and magnetic fields, Ausgrid is guided by
Australian Government agency ARPANSA, which takes
a whole of science approach in relation to electricity
and health. This includes implementing prudent
avoidance measures where practical and feasible.