POWER MANAGEMENT OF INTELLIGENT BUILDINGS IN
SMART GRID
Zoltan Varga
1
and Istvan Szabo
2
1
Department of Automation and Applied Informatics, Budapest University of Technology and Economics
Magyar Tudósok krt.2, Budapest, Hungary
2
Ecotech Zrt./College of Dunaujvaros,Dunaujvaros, Tancsics Mihaly u. 1, Hungary
Keywords: Intelligent Building, Smart Grid, Renewable Energy Sources.
Abstract: The paper presents an intelligent building project, located in Dunaujvaros, Hungary, which is intended to be
connected to a locally set-up experimental Smart Grid. The intelligent buildings are considered as cells in
neural network where the different cells are connected to each other, establishing a real information and
power grid. Here, a unique theoretical solution has been proposed.
1 INTRODUCTION
Recent years the reduction of global energy
consumption and role of the renewable and waste
energy sources in power electric production have
been extensively investigated as island or local grid
connected power generation units. In distributed
power generation the power consumption and
generation can be more precisely synchronized and
balanced, resulting lower power generation units that
can be achieved by intelligent control systems. In
general the power is produced by centralised power
plants that are not suitable for significantly changing
power level. The renewable energy sources offer
promising solutions for small and medium scale
power generation, producing “green” energy. In last
decades a significant effort has been carried out to
increase the role of renewable and waste energy
sources in electric power generation. The renewable
energy sources like solar, wind, geothermal or tidal
energies can be harvested directly of indirectly by
applying generator units. One of the most popular is
the solar and wind energy due to the decreasing
investment costs and relatively high efficiency. In
Europe and globally more and more power stations
utilizing the renewable energy sources are installed
that means the number of power generation units has
been increasing. Generally, these units are only
connected to power grid, supply power for the
consumers but the actual and total produced power
is monitored only locally. Depending on the size of
the power plant, the system should report the
produced power to the local power supplier daily,
weekly or monthly. In many cases the small scale
(micro) power stations are not fully integrated into
power grid, considering the actual state of produced
power. There are numerous projects that investigate
the Distributed Power Generation or Smart Grid
(SG) (Kurohane 2010, KyungGyu 2011) but most of
these projects are only focused on the design and
construction aspects. Generally, the power
production and consumption are considered as a two
different operation that is usually separated in space
and time. A very significant part of the produced
electric power is utilized in buildings, like
households, offices…etc. In lot of cases this power
can be produced locally by micro power stations
where the energy demand for buildings or tools
installed can be provided partly or totally by
utilizing renewable and alternative energy sources.
The buildings equipped with control system is
usually named as intelligent buildings are capable
for controlling and monitoring HVAC, audio,
security and other systems inside and outside the
building. The Intelligent Buildings (IB) can also be
applicable for power management that could be the
solution to interconnect the different IBs and power
sources. So it is desirable to integrate IBs into Smart
Grid because of the following reasons that are
discussed in paper. Due to the enormous amount of
cost required for the structural change of the actual
power generation and transmission systems the
development of intelligent buildings and renewable
energy systems can offer a promising, economical
149
Varga Z. and Szabo I..
POWER MANAGEMENT OF INTELLIGENT BUILDINGS IN SMART GRID.
DOI: 10.5220/0003952901490153
In Proceedings of the 1st International Conference on Smart Grids and Green IT Systems (SMARTGREENS-2012), pages 149-153
ISBN: 978-989-8565-09-9
Copyright
c
2012 SCITEPRESS (Science and Technology Publications, Lda.)
solution for more safety, comfortable and energy
saving power grid.
2 POWER MANAGEMENT
SYSTEMS
The informatics and power electronics in generation
and distribution of electric power has became
dominant in decades and its presence can be
discovered from small power supplies to High
Voltage Direct Current converters (HVDC). Due to
the rapidly growing number of micro- or small
power plants the requirements of power quality
conditioning should be matched to standards,
producing acceptable power quality for consumers.
Because of the large number of nonlinear consumers
and switch mode power supplies the additional
losses in network, harmonics, voltage deviations and
flickers should be taken into consideration and
decreased as low as possible. The high-switching
modern IGBT converters and high speed controllers
provides outstanding possibility to minimize
switching and conduction losses. Due to numerous
advantageous features the converters are applied in
wide range, like DC/DC; AC/AC - DC link
converters and etc. In many cases large number of
converters is used in buildings as well for different
purposes. The converters and all devices related to
them can be applied from mW to MW that means in
power grid they have significant role. According to
the novel green IT solutions the power management
in power grid, a new controlling and monitoring
solutions are proposed to reduce and balance the
power consumption and adapt to changing power
grid. The existing power generation and distribution
system has some problems. First, it has centralized
system architecture. Existing system utilizes
centralized schemes when gathering and analyzing
contexts to operate the power system intelligently,
which causes long service response time. Second, it
delivers electricity and control appliance based on
fixed and predefined values. The Smart Grid and
power management system applied in Smart Grid
offers a viable solution to eliminate or significantly
decrease the discussed disadvantageous features.
The communication between the present and newly
installed elements is one of the key-point of the
whole structure. Globally, the Smart Grid can be
regarded as an organic structure with millions and
millions of participants (cells) and where a definite
controlling and regulation processes are executed.
Here, a special approach of power management is
introduced where the basis of the Smart Grid is the
intelligent building. Naturally, the renewable energy
source are also organic part of the system where the
energy demand is forecasted and monitored in
buildings and grid as well and the whole system is
semi self-autonomous system where the information
is automatically produced and only the information
is processed by different power management
modules, organized into regions as shown later in
Fig. 2.
2.1 Power Management in Intelligent
Buildings
Emerging green IT and Smart Grid technologies that
has been changing the electric power infrastructure
more efficiently, these technologies enable the
power system operator and a consumer to improve
energy efficiency and reduce greenhouse gas
emission by optimizing energy distribution and
management. There are many studies of these topics
with the trend of green IT and smart grid
technology. However, existing systems are still not
effectively implemented in home or building
because of their limitations and its complexity. One
of our main goal is to set-up a local microgrid that
has flexible and programmable structure. The Smart
Grid is a next generation power network utilizing IT
technology as in case of intelligent buildings. Power
management system should be capable to control
and deliver power from suppliers to consumers using
two-way communication reducing the response time,
which leads to energy efficiency and grid reliability
enhancement. The PM system has basically the
capability to sense internal and external
consumption and power generation within a given
unit, cell, domain or region, and grid conditions,
measure power, and control appliances with two-
way communication to electricity generation,
transmission, and distribution and consumer parts of
power grid. Applying intelligent power management
in smart grid, it is possible for the consumer to
dynamically respond to changes in energy
consumption, demand and grid conditions. E.g.:
when the power is low-cost or there is additional
“free” power, the user can allow the smart grid to
turn on certain home appliances that can run at
arbitrary hours. The power managing is a multi-layer
process having large number of connections with
other units resulting high flexibility system. At
lowest layer, these are the cells that are the smallest
measurement and data analysis units, the control
system is implemented in microcontrollers as today
in system of intelligent buildings.
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2.2 Organic Structural System and
Smart Grid
In many cases there are similarities between natural
phenomena and engineering problems. Eg.: the
relationship between the aerodynamics of airplanes
and flying birds is very deep and strong. As it was
discussed earlier the management systems of smart
grid, smart metering, intelligent buildings, and
renewable energy sources and so on are quite
complex where extremely large number of
participants are involved in information and power
flow. Here and (Varga, 2011) a new idea is proposed
where the intelligent buildings in Smart Grid are
considered as a cell, the “smallest” and not divisible
further, as the nerve-cell in nervous system. The
human brain is one of most complex system,
containing billions and billions of nerve-cells that
are formed into regions and connected to each other.
When a specific region of the human brain has
damaged, other parts can partly or entirely take over
the role of the damaged part. There is large
redundancy in the system as it is desirable in Smart
Grid as well. The connection between the nerve-
cells and its spurs are shown in Fig. 1. The nerve-
cells can vary in size and shape and central nervous
system have different types of nerve-cells as the
elements connected to Smart Grid may also vary in
size and function. The following similarities can be
discovered during the analysis of nervous system
and application of intelligent buildings in SG:
• The intelligent building can be considered as a
nerve-cell and the basis of the smart metering
unit in smart grid
• The dentrites of nerves cells are responsible for
sensing the incoming pulses of human body
as the measurement of power, current,
voltage, time... in engineering practice. The
measurement of physical and electrical
parameters in intelligent buildings are also
forwarded to the central unit using different
communication protocols such as WiFi,
Bluetooth and so on. The information from
other buildings is also accepted by
communication ports as other fibres are
connected to dentrites of nerves cells.
According to the number of axons of nerve
cells several types of nerves cells are
differentiated, like multi-polar, pseudo-
unipolar, bipolar or pyramid types.
The connection between other intelligent
buildings is very similar to the structure of
nerve cells as the information (electric pulse)
is transmitted to other nerve-cells.
Figure 1: Schematic layout of a nerve cell [wikipedia].
• If one cell is dropped out, the system can be
operated further
• Different cell types are grouped into regions as
different units (e.g.: power generation,
buildings, data centres...etc.) can also
grouped into “regions”, having different
communication and purposes
This way of approach of intelligent buildings in
Smart Grid can be regarded as a new way of
thinking about SG. In next chapter, basics of the
novel system structure are introduced based on this
topology. In future, this topology will be
investigated in detail and a local smart grid will be
developed for further investigations where a smart
energy distribution and power management system
will be implemented.
3 SYSTEM ARCHITECTURE
In this chapter, the basic topology of the system
architecture of Intelligent Power Management
System (IPM) for energy distribution and
management service in buildings is discussed.
3.1 Intelligent Buildings
The basic unit of the system is the smart buildings
equipped with a microcontroller unit that is able to
communicate with other units, buildings and receive
and transmit data to centres. According to the size of
the building, the complexity of the implemented
system can vary in wide range. In household
applications where own heat and/or electric power
sources are installed the power management system
is able to autonomously regulate the power
consumption of appliances utilizing the locally
POWERMANAGEMENTOFINTELLIGENTBUILDINGSINSMARTGRID
151
Figure 2: Overview of the smart energy distribution and power management with intelligent buildings.
produced power. In case of insufficient power level,
the system send a request to local centres that this
unit requires additional power. Due to the
controllable appliances the power production and
consumption can be balanced according to the
information provided by IBs, local and regional
centres. Inside the building, depending on the size of
building, there is one or more microcontroller
control unit equipped with intelligent sensing
wired/wireless units. This unit is able to monitor the
actual state of the internal and external processes
and the management system. The information should
be evaluated and stored that can be accessible for
other units if it is requested. In buildings large
number of devices can be found that are usually not
controllable, only connected to the AC network and
can be manually operated.
Applying small, inexpensive measurement and
control units theses devices can be apparent for other
units that are the first step to set-up a local smart
grid. Both wired and wireless communication is
important because in buildings where the wiring
between the control unit and device is not solvable
wireless communication should be applied. Fig. 2
shows a possible configuration for a smart
measurement unit and a control unit where the
intelligent power management module should be
implemented in IBs transmitting data to
local/regional centres. Beside the AC network that
can be also used for communication, the local DC
networks can be a new way of power distribution
where the losses can be reduced. In many household
or office devices requires DC power supply, like
laptop, PC, cell phones, LED lamps and so on. Here,
a so called multi-agent based DC-DC converters can
be applied in DC network that balance the power
consumption and offers high efficiency and
reliability. The larger devices like motors,
transformers, fridge, heating units requires AC
supply. The system should handle both DC and AC
measurement and control units that can be connected
as plug-and-play devices as a pendrive to PC. If a
new device is installed and plugged to the power
supply, it is automatically recognized. The IPM
should be able to communicate with certain centres,
gathering information about the environment
(weather-forecasting, grid conditions...) and should
transmit actual state and load patterns determined by
power management system based on load
forecasting with user patterns. In our project two
intelligent buildings have been built and local smart
grid is under development by applying intelligent
sensor and control units and developing a local
power management system. The overview of smart
energy distribution and power management is shown
in Fig. 2. Main goal of our project is to develop and
construct such a local microgrid, containing several
IBs, that is flexible and enlargeable.
3.2 Domains and Regions
In a city large number of different types of buildings
can be found as cells in a network that are connected
to each other by the power grid. In Fig. 2 the IBs are
grouped according to their size and type and
different domains are formed. In Domain #1
buildings named between Cell 1A and An are
situated within the inner circle. These buildings
belong to a certain district or a type and all of them
are connected to directly each other or indirectly
through a local centre. The information provided by
IBs are forwarded to local centres where the
information is further processed and forwarded to
regional centrals that are in direct connection with
central control. Doman #2 and #3 are different
domains that are connected to each other by local or
regional centres. All other participants of smart grid
can also connect to local or regional centres e.g.
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local power plants. Local centres transmits data to
regional centres.
4 CONCLUSIONS
The paper presents a new approach of application of
intelligent buildings and renewable energy sources
in smart grid. The proposed Intelligent Power
Management (IPM) units provide information about
the operation of smart homes and grid conditions,
collecting and analyzing the measurement results,
load patterns and other request that are sent and
received to/from different units. The intelligent
buildings can be considered as organic cells in an
organic structure. The IPM has several numbers of
layers according to the size of buildings and its
complexity also different but in all layer the
information is forwarded to upper layers and other
cells/centres, like weather forecasting centres, other
smart buildings centres where information provided
by IPMs is further processed.
According to the incoming data from IPMs the
control of all elements is performed by controller
units, located in intelligent buildings. A modern
power grid needs to become smarter in order to
provide an affordable, reliable and sustainable
supply of electricity. For these reasons, considerable
activity should have been carried to formulate and
promote a vision for the development of future smart
power grids. Here, a specially designed laboratory
set-up has been presented, providing experimental
verification of future results. The buildings and
laboratories are currently under construction as
shown in Fig. 3. Beside the College of Dunaujvaros
some industrial partner are desirable to involve in
our project to extend the our microgrid and local
Smart Grid and Metering system.
ACKNOWLEDGEMENTS
The authors wish to thank for the support from New
Hungary Development Plan (TÁMOP 4.2.1.- 09/1-
2009-0002) and this work is connected to the
scientific program of the ”Development of quality-
oriented and cooperative R+D+I strategy and
functional model at BME” project.
Figure 3: Intelligent Buildings (laboratories) in
Dunaujvaros.
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