Smart Grid, Smart Controllers and Home Energy Automation—Creating the Infrastructure for Future
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all of the users:
1) Past, spot and the future energy prices from various
suppliers and other associated costs, like lock in period,
offers, discounts etc.
2) If more than one rate is applicable, than the ti me of
day at which the each rate is applicable would be dis-
played.
3) Information regarding the traded volumes.
4) Information regarding various users/connected mem-
bers of the SGCC and their profiles.
It would, typically, be owned and operated by a regu-
latory body on beh a lf of energy suppliers.
2.3. Sources of Energy
The sources of energy could be one, more or all of the
following a) electric supply from the grid b) gas supply
and/or c) other locally available supplies like building
integrated photovoltaic (BIPV), a small local wind tur-
bine with output of few kilowatt and energy storage.
2.4. Controlled Appliances
The controlled appliances would be the various energy
consuming devices in the home. No special intelligence
is required in these devices although it may be helpful to
have some degree of intelligence. To make the subse-
quent discussion easier, the controlled appliances/loads
can be classified as Type-A, Type-B and Type-C. This
classification of loads is not exhaustive nor a standard
classification and is relevan t to this paper only.
Type-A loads are those types which do not allow
much flexibility in terms of the switching their
switching cannot be timed i.e. switching cannot be
much delayed or advanced and are either continuous
or intermittent following a definite pattern. The ex-
amples are Refrigerator, lighting loads, domestic en-
tertainment appliances, and appliances required dur-
ing the cooking etc.
Type-B loads are those which offer flexibility in
terms of the switching i.e. there switching can be
timed. The examples are washing machine, dryers,
dish washers, etc. These operate and switch off auto-
matically after the process is complete.
Type-C loads are those types which do offer flexibil-
ity in terms of switching but need human intervention.
Examples of this type of load are electric iron, vac-
uum cleaners etc.
2.5. Network Interfaces
The main controller interacts with the SGCC through
network interfaces. The network interface could be elec-
trical or an optical interface or combination of these. Ad-
ditionally the interface could be built in the controller.
2.6. MMI Console or the User Interface
The MMI console allows the house owner to interact
with the controller, access the information on the SGCC,
change the settings, update the software, configure the
controller etc.
2.7. The Controller to Appliances Interface
This interface consists of switching devices, typically
relays. Based on the commands from the controller, the
relays would switch in or switch out the power to the
individual appliances. This interface could be integrated
with the main controller or could be a separate module.
Modern day multifunction relays used in the protection
and control application s allow seamless integration of the
controller and switc hing interface.
3. The Main Controller
The main controller is a computer which also houses the
software required to build the energy related intelligence
in the houses. It can, however, be programmed to do
much more [7]. The functionalities that can built in the
controller are enormous and would depend upon the local
energy architecture like the sources of the energy avail-
able to the controlled area, variety and the diversity of
the loads etc.
3.1. Features of Controller in a Simple Residential
or Similar Kind of Controlled Area
In typical residential system the controller would do fol-
lowing tasks:
1) It would receive synchronizing pulses from the
Smart Grid Control centre (SGCC) so that the clock in
the main controller reads the same time as the SGCC
clock.
2) The main controller would contact the SGCC peri-
odically and download the energy updates.
3) It will download the latest energy prices from the
SGCC and use that information to work out the energy
usage charges with the present supplier.
4) Based on the spot and the future prices of the en-
ergy, switching costs, mandatory lock in period of the
present energy supplier and the anticipated/future energy
consumption it would decide whether there is any sup-
plier which is cheaper than the present supplier and in
case it is so, it would initiate a switch over process. Al-
ternatively, the supplier changeover process could also
be initiated by user. The future energy consumption can
be forecasted by the controller based on the previous
energy trends or could keyed in by the user.
5) Type-B loads like washing machines, dryers, water
pumps etc. which are not contin uous and offer flexibility
in terms of switching should be switched when the rate
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