Download INFORMATION ON ELECTRIC AND MAGNETIC FIELDS Willoughby

INFORMATION ON ELECTRIC AND MAGNETIC FIELDS
Willoughby to North Chatswood 33kV underground cabling work
About the work
EMF experienced in everyday life
As part of Sydney Metro Northwest, NRT is required to
install a new power supply for the operation of the
project from Ausgrid’s Willoughby Subtransmission
Substation to Transport for NSW’s North Chatswood
traction substation.
What are electric and magnetic fields?
Electric and magnetic fields (EMF) are found wherever
electricity is present, including home and office
appliances, sub-stations and electrical cables.
All electrical equipment creates electrical and magnetic
fields. The electric field is associated with the voltage
of the equipment and the magnetic field is associated
with the current. In combination, these fields cause
energy to be transferred along electric wires.
With both electric and magnetic fields, the strength of
the field is strongest when close to its source and
diminishes rapidly with distance from the source.
Many common materials, such as brickwork or metal
also block electric fields so they are readily shielded. In
relation to this project, the electric fields associated
with the underground cables are fully shielded by the
cables themselves.
As magnetic fields are related to the current rather
than the voltage, high voltage equipment is not the
only source of magnetic fields encountered in everyday
life. Modern life involves frequent contact with
magnetic fields from a variety of sources such as
appliances in the home and workplace and electrical
machinery. The strength of a magnetic field depends
on the size of the current and decreases with distance
from the source.
Do electrical sources cause health effects?
As we are surrounded by electrical sources in our daily
lives, we are constantly exposed to some level of EMF.
The possibility of adverse health effects due to the
EMF associated with electrical equipment has been
comprehensively studied over several decades
worldwide. To date the scientific evidence does not
establish that exposure to EMF found around the
home, office or near power lines causes health effects.
What are international and Australian
guidelines/standards?
The current International Commission on Non-Ionising
Radiation Protection guideline (ICNIRP, 2010)
regarding magnetic field exposure limits for the general
public is 2,000 milligauss (mG).
The Australian Radiation Protection and Nuclear
Safety Agency (ARPANSA) in December 2006 issued
a Draft Standard on Exposure Limits for Electric and
Magnetic Fields which proposed a magnetic field
exposure limit (Reference Level) for the general public
of 1,000mG.
In July 2007, the Australian Government Radiation
Health Committee revised the magnetic field limit for
the general public upwards to 3,000mG.
In general, EMF from electricity assets will be well
below the Reference Levels in these guidelines,
however, the practice of “prudent avoidance” has been
adopted by the Australian Energy Networks
Association (ENA), of which the Asset Standards
Authority of Transport for NSW is a member.
Prudent avoidance does not mean there is an
established risk that needs to be avoided. It means
that if there is uncertainty, there are measures that
could be implemented to reduce the intensity of the
fields generated.
What is the electric field for the 33kV underground
cables?
As the 33kV line is made up of triple core cables
encased in a plastic conduit and installed underground,
it will not produce any external electric fields.
What is the magnetic field for the 33kV
underground cables?
Based on a project-specific assessment available on
the Sydney Metro website, the magnetic field
contribution would be approximately 1-2mG at the
source (similar to an electric fan and less than 0.05
percent of the ICNIRP reference level) and back to
background levels at any property boundaries.
These levels are at the very low end of the range
normally encountered in everyday life. For example,
household items like electric fans and TV sets have a
measurement range up to 2mG, while electric blankets
and hair dryers have much higher measurements of 530mG and 10-70mG respectively.
Transport for NSW has made information regarding
EMF publicly available through the Review of
Environmental Factors completed in 2015.
How is Sydney Metro Northwest managing and
minimising EMF?
Guided by the prudent avoidance principles, Sydney
Metro Northwest is:
- placing the cables underground rather than installing
less expensive overhead lines
- burying the cables 1-2 metres beneath the road
carriageway away from residential property boundaries
so that the magnetic field contribution at and beyond
them will be lower
- using 3-core cables, which greatly cancel out the
strength of the magnetic fields.
Where can I find more information?
ARPANSA EMF Fact sheets
www.arpansa.gov.au
Ausgrid Electric and Magnetic Fields (EMF)
http://www.ausgrid.com.au/Common/CustomerServices/In-your-neighbourhood/Electric-andmagnetic-fields.aspx#.WQf6QPmGPIU
ENA Electric and Magnetic Fields
www.energynetworks.com.au/electric-andmagnetic-fields
ICNIRP www.icnirp.org
Sydney Metro Northwest Willoughby to
North Chatswood 33kV underground feeder
power line Review of Environmental Factors
(REF)
https://www.sydneymetro.info/station/willoughby
-north-chatswood
WHO EMF Fact sheets www.who.int
For more information, to register for email updates or
to make a complaint phone 1800 019 989 (operating
24 hours a day, 7 days a week), email us at
[email protected], or visit
www.sydneymetro.info.