energy source and distribution, australia: article july 2014 pg61
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With the lure of a green power source and the incentive of government rebates and feed-in tariffs, Australian customers are installing solar photovoltaic panels at an ever increasing rate. While this is positive action for residential customers, it is creating challenges for our electricity networks... Read the entire edition of Energy Source and Distribution online for free here: http://www.calameo.com/read/00037349511a4c89076c6TRANSCRIPT
Australia’s electricity networks were
designed for electricity to flow one
way and with the assumption it will
dry up as it goes down the line.
Solar photovoltaic (PV) integration to the
network is causing extreme and erratic
voltage discrepancies the system is
not equipped to deal with. The solar PV
panels feed power back into the network
during sunlight hours when electricity
is not being consumed, leading to an
oversupply on the lines.
As a result, United Energy (UE) is trialling
an innovative and cost-effective technology
that will allow the existing network to accept
higher levels of solar generated power and
regulate supply.
ZNX Network Services Victoria, a Zinfra
Group company and service provider
to UE’s northern network in Victoria, is
installing low voltage regulators (LVRs) on
UE’s metropolitan, interconnected three
phase network as part of a six month trial.
The self-automated LVR units solve the
common utility problems of flicker and
excessive voltage drop.
The power electronics contained in the
LVR dynamically regulate voltage flow
up or down to within 1 per cent of a
programmable set point, in UE’s case,
stabilising the voltage to a set point voltage
of 230. This precise regulation of voltage
ensures grid stability and compliance with
appropriate service standards.
The units are produced and sourced from
Microplanet, based in Seattle, US. Engineer
Greg Wiegand, from Microplanet, visited
Australia to provide guidance and technical
advice for their use on UE’s networks.
The installation of the units on the pole,
currently involves the placement of
three units on a pole, one for each three
phase wire.
Mr Wiegand explained these units were
initially designed for single wire earth return
(SWER) networks in Queensland and
Microplanet is currently designing a custom
three phase integrated unit that will conform
to height restriction and other regulations on
the UE network.
The new, customised units, known as
U3Ps, will consist of one box containing the
contents of three of the current LVR units.
These units have recently undergone an
extensive testing regime at the Queensland
University of Technology under the Guided
Innovation Alliance (GIA) program.
The GIA is an industry applied research
collaboration established in October
2011 to address barriers and shorten the
pathway to market for new innovations in
the electricity sector.
The GIA program is looking to identify
technologies to counter the problems
associated with the increasing trend of
domestic solar PV installation. It was
through this program UE identified the
LVR units as a solution to their network
difficulties.
ZNX construction supervisor Grant
Attewell said the units provide a very
economical solution to the problem of
voltage regulation.
“The LVR units allow the network
to be updated without updating the
infrastructure,” he said.
“The traditional solution to this problem
would be the installation of a new pole
substation and the high voltage lines
needed to feed it, which would cost at least
three times as much as these LVRs.”
Each LVR can also transmit the activity and
performance of the unit. Incoming voltage,
output voltage, current and temperature of
the unit can be retrieved by downloading it
to a laptop via Bluetooth. This can be done
from the ground, thereby removing the
requirement for a worker to access the unit
up on the pole.
Mr Wiegand said Microplanet is currently
working on improving the data functionality
on future units by installing an SD card that
will record data on a minute-by-minute basis
and be stored for one year. A wi-fi solution
to improve reliability when data gathering is
also being added to future models.
The trials are being conducted in known
trouble spots on the UE network. Three
separate poles will have the units installed
on them by mid-May as part of the trial. In
some cases, UE will use smart meters on
individual premises with known issues to
monitor and gauge their effectiveness.
The first trial devices have been installed
on the low voltage network of Steven-
Woodcrest substation which is a pole-
mounted 300kVA transformer located in
Vermont, Victoria.
Mr Attewell said he is excited about the
potential for the LVRs.
“There are many short-term and long-term
benefits associated with this technology.
The problem of voltage regulation is
addressed with minimal impact on the
end customer and they get a more reliable
service,” he said.
The pole units are small and it all comes at
a fraction of the cost of traditional ways of
dealing with these problems.”
When you take into account the short
installation time, which is as little as 30
minutes, the immediate increased grid
reliability and improved service for utility
customers, the potential for this new
technology to tackle the issues associated
with long runs and the growing use of
domestic solar panels looks very promising.
ZNX is proud to be partnering with UE on
this innovative initiative, bringing their skill,
experience and expertise to the team.
ZNX INSTALL innovative TECHNOLOGY FOR United Energy: LOW VOLTAGE REGULATORSWith the lure of a green power source and the incentive of government rebates and feed-in tariffs, Australian customers are installing solar photovoltaic panels at an ever increasing rate. While this is positive action for residential customers, it is creating challenges for our electricity networks.
ZNX line workers install LVR units
By Helen Roberts-Ferguson, Zinfra Group
How tHe LVR woRks
Microplanet’s LVR combines traditional
power electronics with patented
technology. The LVR will dynamically
raise or lower and balance the incoming
voltage to maintain a constant output
level. The system consists of:
• AnAC-to-ACconverterthatproduces
voltage with a varying magnitude. The
converter drives the primary of a high-
efficiency toroidal transformer.
• Acontrolboardwithamicroprocessor
for measuring the output voltage and
controllingtheAC-to-ACconverterto
precisely maintain a fixed level set by
the customer.
The control board senses line-to-
neutral output voltage and compares
it to the desired reference. Depending
on whether the voltage is too low or
too high, the unit decides if it should be
raising or lowering the voltage, and how
much.ThenitcontrolstheAC-to-AC
converter to adjust the output voltage to
exactly match the reference voltage. The
regulator maintains its output (load side)
voltage even when the power reverses
and is flowing from the customer PV
backwards to the utility.
In the event of electronics failure,
regulation stops but power is not
interrupted. Fault alarms can be sent
to a connected network.
2014 JUL|AUG6