69 / 116
www. e l e c t r i c a l c o n n e c t i o n . c om . a u
69
already widely available in a lot of
appliances but can also be used for
generation systems. For instance, a
utility could send out a signal either
because of power quality, cost or
an agreement with the customer to
reduce their generation by a nominated
percentage or disconnect from the grid
for a period of time.
The signals may be communicated via
an old fashioned ripple control
but, according to Glen, are more likely
to be sent via a dedicated link such as
3G to the installation or some form of
aggregation by the utilities over pole top
communication systems. They will be
used when there’s excess generation on
the network but also to export energy
from customers back onto the grid.
“At the moment we’re all about
stopping excess generation but there
may be times when grid support
modes are needed. At these times
utilities can request energy from
customers who have the facility and
have agreed to allow their energy to
be exported on demand – this will tie
in with some sort of financial benefit
to the customer.”
Voltage rise and voltage drop
calculations for grid connected
systems as part of the application
process have also been addressed in
the updated standard. NSW utilities
adopted the AS/NZS 4777.1 draft
recommendations in back in August
2013 and the utilities in other states and
territories will no doubt adopt them as
soon as it’s published.
“You’ll have to keep voltage rise
below 1% per network segment – so
1% from the inverter output to the
switchboard and then 1% from the
switchboard to the point of common
coupling which is usually the service
mains arm of the building. This is
hard to do on rural properties that often
have 16mm mains coming in
and long AC supplies from the
switchboard to where the house is and
where the solar is likely to be installed –
in this kind of scenario it’ll be well over
1% over 20m-30m. That calculation not
only needs to be done but needs to be
complied with as a 2% overall rule will
come into force with the publication of
AS/NZS 4777.1.”
GAIL
BRIGSY
DELIVERED DIRECT
TO YOUR DOOR
PHONE 1800 623 214 or visit
WWW.TRADESTUFF.COM.AUElectrical Estimator’s Labour Unit Manual
14th Edition
CODE 583 . . . . . . . . . . . . . . . . . . . . . . . $120.00 (inc. postage)
This updated labour unit manual has been produced to assist contractors
to allow a realistic labour allocation to their jobs. These units have
been developed over a number of years using actual time studies. This
publication also includes a USB estimating spreadsheet and templates for
calculating hourly charge out rates and minor installation quotations.