COMMUNICATION
REQUIREMENTS FOR SCADA

Communication media should have:
* High Reliability
* High Availability
* Rapid Response
* Transparency
* Economy
* Flexibility
* Maintainability
Modes of Communication
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PLCC
Leased Telephone circuits
Microwave Communication
Fibre Optics Communication
Satellite Communication
PLCC
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High voltage lines themselves are used as communication
links.
Carrier Frequency: 50-300 KHz.
3 channels are used generally:
Main-Channel ->
speech channel – 300 Hz to 2000 Hz
Telemetring- 2000 Hz to 3400 Hz
Protection-Channel-I ->
speech channel – 300 Hz to 2000 Hz
Teleprotection- 2000 Hz to 3400 Hz
Protection-Channel-II (Backup-Protection)->
speech channel – 300 Hz to 2000 Hz
Teleprotection- 2000 Hz to 3400 Hz
Advantages:
1.
2.
PLCC
High reliability
All channels are available for dedicated use by
power-utility alone
Disadvantages:
1.
2.
3.
Cost of insulating communication equipment is high
High noise level due to Corona
High speed data-transfer not possible because of
Bandwidth limitations.
Microwave Communication
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Line-of-sight communication
Requires repeaters at 50-60 kms. Intervals
Provides sufficient bandwidth to meet the needs of
power utility
Higher availability than PLCC, availablity not affected by
maintenance or faults on the power lines
Suffers from multipath-fading effect
In India, WPC (wireless planning & co-ordination) wing
has assigned 2.3-2.5 GHz and 2.8-5 GHz bands to power
sector usage.
Digital Microwave Systems
Leased Telephone Circuits
•Simple solution, no need to develop own
dedicated communication facility by
power utility
•Availability of this mode of
communication at remotely located
substations is the deciding factor
Fiber-Optic Communication

•
Fiber-optic communication is a method of transmitting information from
one place to another by sending light through an optical fiber. The light
forms an electromagnetic carrier wave that is modulated to carry
information
The process of communicating using fiber-optics involves the following basic
steps:
Creating the optical signal using a transmitter
Relaying the signal along the fiber, ensuring that the signal does not
become too distorted or weak
Receiving the optical signal and converting it into an electrical signal
INPUT
Analog/Digital
Interface
Voltage to
Current
converter
Source to
Fiber
Interface
Light
Source
Optical Fiber
Fiber to
Light
Detector
Interface
Light
Detector
Current to
Voltage
converter
Analog/Digital
Interface
OUTPUT
Fiber Optic Communication

Advantages:
The ability to carry much more information and deliver it with greater fidelity
than either copper wire or coaxial cable.
Fiber optic cable can support much higher data rates, and at greater distances

The fiber is totally immune to virtually all kinds of interference, including
lightning, and will not conduct electricity. It can therefore come in direct
contact with high voltage electrical equipment and power lines.
POWERGRID uses overhead fiber optic communication:
OPGW (optical ground wire cable)
ADSS (all dielectric self supporting cable)
WRAP AROUND
Fibre Optic Systems
INTEGRATION OF DIGITAL & ANALOG
NETWORKS
OPGW
PLCC
FODP
OLTE
2 MB/S
ADD DROP MUX
2 MB/S
VOICE
CARD
DATA
CARD
MICROWAVE RADIO
TERMINAL
OPGW
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•
•
•
•
•
•
OPGW (optical ground wire) replaces
shield wires
Provides lightning protection
Provides communication
Lightning short circuit damage
Installation requires long term outage
Expensive
Superior performance
ADSS F.O
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ADSS (all dielectric self supporting) which
is mounted at various locations, typically 3
to 10 meters below the phase conductors.
ADSS costs less than OPGW
Higher fiber count than Wrap type.
Can be installed on towers not designed
for shield wires.
Suitable for hot line installation
WRAP AROUND F.O
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Wrap-type which is wound around
shield wires and, in some instances,
around energized conductors
Hot-line installation is difficult
Cost more than ADSS, but less than
OPGW
Need a shield wire
No operation problem is observed
OVERHEAD CABLES FOR
POWER UTILITIES
OPGW
WRAP
ADSS
AERIAL OPTICAL FIBRE CABLES
MOISTURE BLOCKING COMPOUND
AL COATED STEEL STRAND
AL STRAND
OPGW
AD\AS\RKG\JP\FIBCROSS
LOOSE TUBE
POLYESTER TAPE
XLPE SHEATH
AL TUBE
FIBRE
STRENGTH MEMBERS
ADSS
WRAP AROUND
FIBRE OPTIC CABLE INSTALLATION
OPGW
WRAP AROUND
ADSS
AD\AS\RKG\JP\FIBINST
SATELLITE COMMUNICATION
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A geostationary satellite is
used as an active repeater.
Modulated signals are send
from earth VSATs in 6 GHz
band to the satellite.
Signals are beamed back to
earth in 4 GHz band.
Roundtime propagation delay
of 540ms exists
Communication is interrupted
during eclipses.
Date of commissioning : January 2002
RAMAGUNDAM
PEDAPALLI
DURSHED
JAMMIKUNTA
GAJUWAKA
WARANGAL
VIZAG SWS
SHAPURNAGAR
VIDYUTH SOUDHA
GHANAPUR
BOMMUR
KAKINADA
CH.GUTTA
VTPS
HYDERABAD 400
BHIMADOLE
N’SAGAR PH
VIJAYAWADA
TALLAPALLI
SRISAILAM PH
SRISAILAM LBPH
KURNOOL
APSEB
Lingasugur
HUBLI
SOMAYAJULAPALLI
RTU’S
82
N
GOOTY
MUDDANOOR RTPP
DAVANAGERE
CHINAKAMPALLY
ANANTHAPUR
BANGALORE
KEB
CHENNAI
KUMBALGODI
PONDY
RTU’S
SOMANAHALLI
SRIPERUMBUDUR
RTU’S
P
05
SP.KOVIL
22
VILLIANUR
PONDY
KANNUR-B
SALEM400
CENTRAL
PANRUTI
SALEM230
NEYVELI
ERODE
SECTOR RTU’S
22
CHIDAMBARAM
INGUR
KOZHIKODE
LEGEND
RSCC (1)
MYLADUTURAI
CPCC (1)
PONGALORE
UDUMALPET
TRICHY
TRICHUR NORTH
ADANIKOTTAI
CHALAKUDI
MADURAI400
RTU’S
30
VIAKKAM
PALLOM
KAYANKULAM
KUNDRA
KARAIKUDI
SIVAGANGA
MADURAI
TNEB
RTU’S
PARIPALLI
SLDC (4)
SUB-LDC / SCC (14)
PUDUKOTTAI
THIRUMAYAM
KALAMASSERY
KSEB
KOVILVENNI
THIRUVARUR
ORTHANADU
FIBRE OPTIC LINK 110/132kv
FIBRE OPTIC LINK (220kv)
FIBRE OPTIC LINK (400kv)
FIBRE OPTIC LINK (SEB)
40
MICROWAVE LINK (35 links)
TRIVANDRUM NORTH
VYDYUTHI BHAVANAM
SATELLITE LINK (KEB)
SLDC
WRTCC GOA
WR-SC&C Communication system
Asoj
GEB Sector
Kalwa
Vav
Asoj
Mapusa
Phadge
Haldarwa Jambuva
Boiser
Vapi
LEGENDS
OPGW
Green - ULDC Wideband Link
U/G – OFC
BLUE - PDT Link
Leased Link
Black - PLCC Link
Both Main and Std. By Data PLCC Channel
St. By Data PLCC Channel
Main Data PLCC Channel
62 Nos. PLCC Equipment
109 Nos. Wideband ULDC Eqpt
SEB’s Wideband Equipment and OFC
Raigarh
Seoni
Sipat
Vadodara
POP
ILA-387
Indore
Gandhar
Dehgam
Bina-400
MPSEB Sector
Indore
Sub-LDC
ILA-174
Itarsi
Satna-220
Itarsi-220
CSEB Sector Gwalior
Korba-West
Bhatapara
Bina
Bhilai-220
Raipur ILA-362
Korba
STPP
ILA-311
SLDCJabalpur
Satna
ILA-194
Khandwa
Rajgarh
Korba-East
CSEB Sector
Bhilai-400
(SLDC)
Asoj
Kakrapar Kawas
Bhopal-400
Sub-LDC
Tarapur 3&4 Tarapur 1&2
Jabalpur-220
Ponda
Borivalli
Gotri
SLDC
Jambuva
Haldarwa
Katni-220
Kalwa
WRLDC
Jabalpur-400
V’chal ILA-368 ILA-702
Dhule
Phadge
Chandrapur B’Vati
Raipur
KR-13
Vindhyanchal
Itarsi
Wideband Channel Routing for Madurai Sub-LDC
Peramballur
Echengodu
Tanjore 230
Erode Sub-LDC
(Erode)
Pugalur
Chennai
Sub-LDC
(NLC TS-I)
Trichy 400
Madurai North
Trichy 230 Samayapuram
Paramakudi
Madurai
Sub LDC
Sivagangai
Karaikudi
Madurai 400
Podukotta Adanakottai
C
Orthonadu
Kovilvenni Thiruvarur
Existing RTU – 9 nos.
TTPS
Theni
Kayathar
E
Sembatti
Pariyar PH
Sathur
Tuticorin Auto
Kodayar PH2
Existing RTU integrated
New RTUs – 13 nos.
PLCC Link
S R Pudur
MW Link
COMMUNICATION NETWORK FOR KERALA
Wideband Routing from Sub-LDC to SLDC,(Kalamassery)
MW Link
RSCC,Bangalore
(Udumalpet)
FO Link
Kannur-B
Kozhikode -B
T. North
Chalakudy
Kalamassery
Vidyuthi
Bhavanam
Trivendrum
North
Paripally
Kundra
Kayamkulam
Pallom