MYSORE 2013

Preferential Subject 1: Role of ICT in Power System

COMMUNICATION ALTERNATIVES FOR SMART GRIDS: THE INTEGRATED

APPROACHJaume Darné and Claudio Rizoli

Spain

D2 – 01 - 16

MYSORE 2013Energy Network Challenges

• High data rates

• High scalability.

• QoS support

• Cost-effective.

• Interoperability of equipment from different vendors

• Service integration flexibility.

• Efficient frequency reuse in Radio Links

• Seamless mobility

• Cyber security.

• Flexibility.

MYSORE 2013Quality of Service

Not a general parameter. Specific for every Service

Basic Requirements concerns to Latency and Reliability

Requirements are balanced by Cost

Wired media can offer guaranteed QoS

Packet radios at ISM bands cannot offers a sustainable

QoS

Packet radios at private bands may offer QoS

Mesh topologies increases the possibilities of QoS

MYSORE 2013Interoperability

Smart Grid Communications: QoS Stovepipes or QoS Interoperability. Bakken, Schantz and Tucker

MYSORE 2013Efficient Resources Reuse

• In Smart Grid, Telecom is a resource not an objective

• Smart Grid requires massive Telecom deployment.

• TCO must be considered

• There is no universal Telecom technology.

• FO, Cooper Cable or Radio should be carefully implemented

• Every application may require specific technology.

• Efficient frequency reuse in Radio Links

• RF channels should be planned considering interferences

• Radio ISM bands may be blocked because external

interferences.

• Mesh topologies increase the connectivity opportunities.

MYSORE 2013Flexibility for Long Life

• Smart Grid requires huge investments with planned ROI

• Network behavior must be open to new Technologies

• Network must use suitable technology oriented to the

application

• Substitution of a network technology cannot affects to the

others

• Interoperability is a desired feature

• Services must be Technology independent

• Technological Components can be changed with minimal

network disturbances

MYSORE 2013WiFi Radio Spectra

MYSORE 20132.4 GHz WiFi, Real Spectrum

MYSORE 2013Systems at 2.4 GHz

• 2.4 GHZ belongs to the Industrial, Scientific and

Medical bands which are free of use only with some

restrictions in transmitted power.

• Other popular ISM band are located around 5 GHz.

• Comercial Systems operating at 2.4 GHz are:

• WiFi is defined in the IEEE 802.3 group of

standards.

• Wimax based on the IEEE 802.16 standards

• Bluetooth initially IEEE 802.15.1 and now BSIG

• Zig-Bee defined by IEEE.802.15.4

MYSORE 2013Network Topology

MYSORE 2013Radio Preferred Topologies

Bus topology cannot be used. Radio space is a shared media

Star. The most widely used in commercial Wi-Fi applications

Tree. Commonly used in low density areas

Line. Basically is a Point to Point architecture with 2 transmitters

Mesh. Requires flow control complexity

Ring. Technically possible but not widely used

MYSORE 2013Packet Radio

• Radio Transmitters may be full duplex or half duplex

• Full Duplex Radio Data Transmitters normally are used

in PtP links

• Packet Radios are Half Duplex Radio Data

Transmitters

• PR alternatively switch on/off the Tx and Rx parts

• Tx and Rx uses the same RF channel alternatively

• CSMA-CA protocol is used to minimize the collisions

• Some systems are able to jump the channel 1600 T/s

MYSORE 2013WiFi, Delay Probability

MYSORE 2013Routing Capacity

1

2

3

10

4

Bloc

king

pro

babi

lity

Normalized Traffic (E/N)

MYSORE 2013The IEEE 802.11n Standard

• Last and widely used WiFi standard

• Covers both bands 2.4 GHz and 5 GHz

• May use double bandwidth channels (40 MHz)

• Collaborative system with multiple radios and

antennas

• Implements MIMO and Beam Forming techniques

• Suitable for Mesh topologies

• Efficient configuration in dense areas may be

complex

MYSORE 2013New Improvements

New trends are focused to increase the effective

bandwidth and QoS

• Channel aggregation

• Multiband aggregation

• New ISM bands in use for packet radio

• Use of Routing Protocols improve the QoS

New Proprietary protocol solutions promises

unprecedent efficiency and QoS in homogenous

network.

Hardware with low energy consumption eases its

placement in unattended places

MYSORE 2013Radio Wave Propagation

• Wave propagation is a frequency dependent issue

• Losses increases proportionally to the frequency

• Loss, Diffraction (Scattering) and Reflection must to

be main parameters to consider

• For long ranges the local effects are averaged by the

distance

• Smart Grids are always “Short Range”

• In GHz wavelength range, walls are “reflectors” and

streets are “waveguides”

MYSORE 2013Propagation Models

• Path losses are not an easy matter to calculate.

• Different models are proposed covering different

cases

• Statistical models are suitable for system simulations

• Empirical models are site specific but more reliable

• Smart Grid practically limits the distances to a few

Km

• Free Space, Friis, Weissberger and Two Ray models

should be discarded

• HATA models and its variants gives optimistic results

in WiFi bands because his validity ends at 1.5 GHz

• COST models family seems to be more appropriate

MYSORE 2013Network Node

MYSORE 2013Network Node Application

MYSORE 2013Question 1.35

Authors highlighted the importance of implementing Point to Point links rather than multidirectional diffusion ones. Does it beneficial in terms of cost?

• Point to point link is a consequence to use of

directional antennas

• Directional antennas maximises the desired signal

while the unwanted interferences are attenuated

• In the counterpart setting the node requires to point

the antennas

• In terms of cost, PtP links are more expensive and is

necessary to balance with the technical benefits

MYSORE 2013Question 1.36

Do you consider using Point to Point links across the entire network to share media with other services?

• Point to point link is an expensive solution which should

be reserved for mission critical links and / or in highly

interfered areas.

• In a mesh network, a certain node may use different

type of antennas depending of the nature of the link

• Mesh networks based on standards takes advantage of

the use of specific resources suitable for determinate

situations

MYSORE 2013