Developments Towards an International Standard for Broadband PLT

1
Broadband Developments
ISPLC 2005
International symposium Power Line Communications
2
PLC Generic Model
Backhaul network
High Voltage
Xmission Equipment
pt to multi-pt
CPE
Phone(s)
pt to pt
Fibre Network
PC
Medium Voltage Grid (Last Mile)
Low Voltage (Last 100m)
In-Premise (Last Inch)
CPE - Customer Premise Equipment
3
Current Trends Computing is ubiquitous and the
world is networked
4
Everywhere, Theres Exploding Demand for
Communications Bandwidth
Worldwide Access Lines
Changing Traffic Patterns
2B
Internet Session 20 - 30 minutes
1B
Voice Call 3 minutes
Average Hold Times

• It took about a century to install the worlds
  first 700 million phone lines
• More than 100 million additional Internet users
  will come on-line in 2001

Jen
5
Technology Accelerators
6
An Upward Bandwidth Spiral
jen
7
Broadband Access Market
Internet Penetration (source NetValue)
Broadband Percentages of Total Penetration
8
Commercial Status
SENER
ELFORSK, VATENFALL
NUON
PATTERN

• US Activities

MVV , PPC
EDF
ENEL
UNION FENOSA
9
Worldwide PLC Activities
Norwegen Stadtwerke Bergen Schweden Sydkraft,
BirkaEnergi Finnland EVU-Verband
Island LinaNet Reykjavik Energy
China Provinz Sechuan
UK/SSE
Indianapolis, Boston
D RWE, EnBW, MVV, onelineA - TIWAG, EVN, Stw.
Salzburg, EVO CH - DIAX
Spanien Endessa Portugal EdP Italien Enel
Korea Keyin
Kuwait ITS Qatar Israel Mainnet, ITRAN, elLine
Malaysia FibreCom Multimedia-Ministerium
Brasilien Copel Cemig InfoPaolo
Südafrika (Siemens)
Argentinien (ascom) Chile (Endesa)
10
Pictures PLC around the World
11
Opportunities for Power Utilities as
Communications Bandwidth Suppliers

• Three broad domains of opportunity
• As backbone bandwidth wholesalers
• As distribution network last milesuppliers
• As in-building network suppliers
• More than 100Electric Utilities authorized as
  Telecom Carriers

12
Broadband Access Options
100
Wireless (Time-SpaceProcessing)
VDSL
Cable Modem
10
Wireless(steerable beam)
ADSL
DSL-Lite
Bandwidth
1
V.90
Fixed Wireless(stationary beam)
ISDN
0.1
56K
33.6
28.8
VF Modem
14.4
0.01
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
Deployment Year
Jen
13
Broadband Local Distribution Technologies
Todays Contenders
DSL Cable Modems Fixed Wireless (2.4GHz) Satellite
Cost/mo. Avg. 60 45 145 65
Installation Avg. 30 250 1250 400
Est. Subscribers 2M 3.4M 140K 750K
Projected Subs. 2005 12M 14M 1.5M 2.4M
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Standard Communication characteristics

• Unique frequency specification

15
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance

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Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise

17
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise
• Constant bandwidth

18
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise
• Constant bandwidth

19
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise
• Constant bandwidth
• Standard architecture

20
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise
• Constant bandwidth
• Standard architecture

21
Standard Communication characteristics

• Unique frequency specification
• Characteristic impedance
• Minimum noise
• Constant bandwidth
• Standard architecture

22
Leaky cables _at_1Mhz to 30Mhz

• At these frequencies not all the signal is
  transmitted down the cable-it leaks power
• So some of the high frequency signal emanates as
  electromagnetic radiation
• Hence power cables can be considered as linear
  antennas and
• Low efficiency

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Coupling via the Mains Network
LN
50O
50µH
Source
Victim
Attenuation, dB/30m
30
20
10
Distribution network
Mains only
0.1
1
10
MHz
Frequency
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Radiated emission
Mains cable
Equip1
Mains cable
plc1
Conducted emission through mains
Conductio through earth impedance
Radiated emission cable to cable
Mains cable
input
Mains cable
Radiated emission case to case
plc2
External mains interference
Electromagnetic radiated emission and coupling
Interference
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Physical structure of LV network
Armoured Cable

• Underground overhead distribution
• Armoured cable
• Conditioning units (CU) may be used

Conditioning Unit (CU)
Network
MV network
LV network
Source York EMC Services Ltd
Internal mains network
CU
LV network
SUBSTATION
CU
Data network
Data port
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Frequency Bands

• General Frequency Bands
• 1.6MHz to 30MHz
• Division Access band 1.6MHz-10MHz
• In-house band 10MHz to 30MHz
• USA variation and extension for Overhead systems
• Access 10MHz -80MHz
• In-house 1.6MHz to 10MHz

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Spectrum Technologies
30 kHz
300 kHz
3 MHz
30 MHz
MEDIUM FREQUENCY
LOW FREQUENCY
HIGH FREQUENCY
GROUND WAVE
SKY WAVE
SPACE WAVE
ADSL 25 kHz - 1.1 MHz
VDSL 1.1 - 30 MHz
DPL 1.1 - 30 MHz
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Scope
IONOSPHERE
SKY WAVE 3 - 30MHz
Q
SPACE WAVE 0.1 - 30MHz
GROUND WAVE 0.1 - 3MHz
LONDON
ROME
G
NEAR FIELD
SUBURBAN
RURAL
Average UK ground
0 km
5 km
200 km
1500 km
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Established Communication Services in the 1MHz to
30MHz

• Broadcasting Channels
• Amateur Radio
• Mobile Communications
• Distress frequencies
• Military communications
• Radio astronomy

31
Regulatory Landscape for PLT
ITU

IEC
CISPR
Inter Governmental organisations
European Commission
European Parliament
CIGRE
IEEE
CENELEC
ETSI
National Standards Organisations
Government Regulators
Industry Associations
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IEEE Standards Board -PLT

• Committee Structure
• Power Engineering Society
• Communications Society
• Electromagnetic Compatibility Society
• Antennas and Propagation Society
• All are welcome

33
Sources of Interference

• Noise caused by impedance mismatch
• Impulse noise ingress from electrical appliances
• Narrow band ingress from SW broadcast
• Attenuation of the network
• impedance variations
• general interference
• poor power quality

34
The problem

• we measure E or H fields at some distance from a
  source, but need to know the field strength value
  at some other distance
• it is often assumed that fields vary with
  distance as 1/r , 1/r2,1/r3,1/r n
• when is this right?
• magnetic field H from infinite straight wire
  carrying steady (DC) current does indeed vary as
  1/r
• but our wires are finite in length, and arent
  carrying DC

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What about real-size, finite dipole?

• for simplicity, most text books derive only far
  field for practical antennas, by integrating just
  the 1/r terms
• Jordan Balmain (Electromagnetic Waves
  Radiating Systems) do the full solution
  (including near-field terms) for arbitrary length
  dipole- assumes usual sinusoidal current
  distribution
• special case if dipole is half wavelength (or odd
  multiple)

36
Regulation for Radio Service Protection

• Main goal Protection of radio services by
• ? Define radiation limits.
• ? Same limits for all telecom-products (e.g.
  xDLS, ISDN, PLC,)
• ? Measurement method for in situ measurements
• Hence, requirements for new telecommunication
  equipment are more stringent than for other
  equipment (e.g. LAN..)

37
Mitigation Methods

• In case of interference complaint, several
  actions can be done by the operator
• Introduce second injection point
• Apply Notches
• Before that the regulator will evaluate that
• The complaint by the user is justified
• The user has done all possible to eliminate the
  complaint

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Spectral Characteristics of modern
Telecommunications Signals

• Modern telecommunications technologies are
  digital technologies.
• OFDM technologies are the majority, but some
  other multi-carrier technologies and some
  spread-spectrum single-carrier technologies also
  exist.
• These technologies can be designed in such a way,
  that
• the carrier spacing of an OFDM system is much
  higher than 10 kHz, and each carrier is modulated
  by randomized modulation (e. g. QAM)
• the channel bandwidth of multi-carrier
  technologies is very much higher than 10 kHz

39
Developments towards the PLT Standard

• Coexistence between Broadband PLT and Wireless
  communications services
• Broadband may be assessed as a communication
  service causing intentional or unintentional
  radiation
• Intentional radiators use EM waves as a carrier
  of information typical of wireless
  telecommunications services-Licensing required
• An unintentional radiator is primarily a
  wire-bound service that generates radiated
  emission as a secondary unwanted by-product
  Broadband PLT should be treated as a
  unintentional radiator wire-line service with
  radiated emission treated as a parasitic
  undesirable

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Broadband PLT And EMC Limits

• If Broadband PLT is unintentional radiator it is
  subject to EMC Limits
• Two basic EMC Standards-
• IEC CISPR developed by International committees
  and generally adopted as national law
• If the laws are not adopted, national regulatory
  bodies provide their own legislation

41
CISPR 22

• Conducted limits for products
• Wire-line systems which are
• DSL systems
• Cable modem systems and
• Broadband PLT systems
• The same standard applies to all three systems

42
IEC CISPR 22 and Broadband PLT

• Broadband PLT requirements close to CISPR22
• CISPR22 specifies limits for information
  technology equipment (ITE) and distinguishes
  between
• Mains Ports-power supply ports and
• Communication ports
• However PLT operates with a single port for mains
  and data communications- Multipurpose Port

43
Interference Potential of a Port According to
CISPR22

• CISPR22 covers DSL and Cable modem services
• CISPR22 charter was modified to include PLT
  Broadband services and the multi-purpose port
• This is a product standard

44
CISPR22 Interference potential assessment

• The interference potential is assessed by
  connecting the port of the equipment under
  investigation to an Artificial Network which
  represents the real World as closely as possible
• For the telecommunications port a T-shaped
  impedance stabilization network known as a T-ISN
  represents the artificial Network
• For the mains port a V-shaped ISN is used to
  represent the Artificial network (V-ISN)
• Measurements based on the T-ISN delivers the
  asymmetrical voltage , Uasym which represents the
  disturbance potential of the communicating signal
  

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Limits for Mains and Tele-com Ports
Frequency MHz Mains Port (V-ISN) QP/dB (uV) Telecomm Port (T-ISN)QP/dB(uV)
0.15-0.5 66-56 84-74
0.5-5 56 74
5-30 60 74
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Development of M313

• CISPR22 is a product (device) standard
• M313 mandate covers the complete network which
  means the actual power lines
• Also this new law will cover only complaints of
  interference
• This however does mean that modems causing
  interference may be made to be switched off if it
  is causing interference to established radio
  services
• The eventual outcome will be a harmonised
  European standard
• Current proposals from EU countries are wide
  ranging -

47
Radiated Emission standard proposals in
Europe
Radiated Emission Standard
Fv,sbsbbbmb bmb
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Summary

• Limits for radiation are still under discussion
  - EC granted a mandate313 to ETSI/CENELEC/CEN to
  develop European harmonized standard
• Main considerations
• Balance with existing radiation caused by other
  systems e.g. LANs etc.
• Balance should be made between the protection of
  the Spectrum and the introduction of new
  technologies and their national economic benefits

49
Near and Far Field Radiated Impedance Measurements
Z(µ/?)½
10K
Electric Field predominateslow current,high
voltage radiator
Wave impedance
O
Far Field
1K
Near Field
Plane Wave Z377?
377
Wave ImpedanceE/H

High current,low voltage,low impedance
Magnetic Field predominates
100
d gt?/2?
dlt?/2?
Distance metres
1
D?/2?
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LCL and Impedance

• Variation in the LCL and Impedance
• Variation in Impedance with LCL may be in phase
  for the Kitchen
• However the same relationship for the garage is
  not so close
• Measuring at different points in the same house
  and same wiring does introduce errors leading to
  variable LCL and Impedance

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Emissions Normalised to 13m
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Committees and standards to Monitor

• EMC Directive 89/336/EEC
• General EEC IT committees
• Cenelec SC205A especially WG10-high frequency
  committee
• TC210 Cenelec EMC committee
• ETSI PLT covers all broadband issues
• FCC15 for USA Broadband PLT developments

56
Key Measurement Parameters

• Noise floor for urban, semi-urban and rural
• Conducted emission
• Common mode emission and electric field
• Longitudinal Conversion Loss-LCL
• Impedance of line
• K factor
• Regression and
• There inter-relationship in the near and far
  field
• Relationship with single and three phase systems
  for Ring Main and Tree Branch wiring
  architecture

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For Further Information

• John Newbury
• Power Communications Research
• The Open University
• Manchester , England
• Tel [phone]
• Email j.e.newbury_at_open.ac.uk