COMMUNICATION COMMUNICATION REQUIREMENTS FOR SCADAREQUIREMENTS FOR SCADA

Communication media should have:Communication media should have: * High Reliability* High Reliability * High Availability* High Availability * Rapid Response* Rapid Response * Transparency* Transparency * Economy* Economy * Flexibility* Flexibility * Maintainability* Maintainability

Modes of CommunicationModes of Communication

PLCC Leased Telephone circuits Microwave Communication Fibre Optics Communication Satellite Communication

PLCCPLCC High voltage lines themselves are used as High voltage lines themselves are used as

communication links.communication links. Carrier Frequency: 50-300 KHz.Carrier Frequency: 50-300 KHz. 3 channels are used generally:3 channels are used generally: Main-Channel ->Main-Channel -> speech channel – 300 Hz to 2000 Hzspeech channel – 300 Hz to 2000 Hz Telemetring- 2000 Hz to 3400 HzTelemetring- 2000 Hz to 3400 Hz

Protection-Channel-I ->Protection-Channel-I -> speech channel – 300 Hz to 2000 Hzspeech channel – 300 Hz to 2000 Hz Teleprotection- 2000 Hz to 3400 HzTeleprotection- 2000 Hz to 3400 Hz

Protection-Channel-II (Backup-Protection)->Protection-Channel-II (Backup-Protection)-> speech channel – 300 Hz to 2000 Hzspeech channel – 300 Hz to 2000 Hz Teleprotection- 2000 Hz to 3400 HzTeleprotection- 2000 Hz to 3400 Hz

PLCCPLCCAdvantages:Advantages:1.1. High reliabilityHigh reliability2.2. All channels are available for dedicated use by All channels are available for dedicated use by

power-utility alonepower-utility aloneDisadvantages:Disadvantages:1.1. Cost of insulating communication equipment is Cost of insulating communication equipment is

highhigh2.2. High noise level due to CoronaHigh noise level due to Corona3.3. High speed data-transfer not possible because High speed data-transfer not possible because

of of Bandwidth limitations.Bandwidth limitations.

Microwave CommunicationMicrowave Communication

Line-of-sight communicationLine-of-sight communication Requires repeaters at 50-60 kms. IntervalsRequires repeaters at 50-60 kms. Intervals Provides sufficient bandwidth to meet the needs of Provides sufficient bandwidth to meet the needs of

power utilitypower utility Higher availability than PLCC, availablity not affected Higher availability than PLCC, availablity not affected

by maintenance or faults on the power linesby maintenance or faults on the power lines Suffers from multipath-fading effectSuffers from multipath-fading effect In India, WPC (wireless planning & co-ordination) In India, WPC (wireless planning & co-ordination)

wing has assigned 2.3-2.5 GHz and 2.8-5 GHz bands wing has assigned 2.3-2.5 GHz and 2.8-5 GHz bands to power sector usage.to power sector usage.

Digital Microwave Systems

Leased Telephone CircuitsLeased 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 CommunicationFiber-Optic Communication Fiber-optic communication is a method of transmitting Fiber-optic communication is a method of transmitting

information from one place to another by sending light through information from one place to another by sending light through an optical fiber. The light forms an electromagnetic carrier wave an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry informationthat 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

Analog/DigitalInterface

Voltage toCurrent

converter

LightSource

Source toFiber

Interface

Fiber toLight

Detector Interface

LightDetector

Current toVoltage

converter

Analog/DigitalInterface

OUTPUT

INPUT

Optical Fiber

Fiber Optic CommunicationFiber Optic Communication Advantages:Advantages: The ability to carry much more information and deliver it with greater The ability to carry much more information and deliver it with greater

fidelity than either copper wire or coaxial cable.fidelity than either copper wire or coaxial cable.

Fiber optic cable can support much higher data rates, and at greater Fiber optic cable can support much higher data rates, and at greater

distancesdistances The fiber is totally immune to virtually all kinds of interference, The fiber is totally immune to virtually all kinds of interference,

including lightning, and will not conduct electricity. It can therefore including lightning, and will not conduct electricity. It can therefore come in direct contact with high voltage electrical equipment and come in direct contact with high voltage electrical equipment and power lines. power lines.

POWERGRID POWERGRID uses overhead fiber optic communication:uses overhead fiber optic communication:

OPGW (optical ground wire cable) (optical ground wire cable)

ADSSADSS (all dielectric self supporting cable) (all dielectric self supporting cable)

WRAP AROUNDWRAP AROUND

Fibre Optic Systems

OPGW

FODP OLTE

ADD DROP MUX2 MB/S

MICROWAVE RADIO TERMINAL

2 MB/S

INTEGRATION OF DIGITAL & ANALOG NETWORKS

PLCC

VOICE CARD

DATA CARD

OPGWOPGW

OPGW (optical ground wire) OPGW (optical ground wire) replaces shield wiresreplaces shield wires

• • Provides lightning protectionProvides lightning protection• • Provides communicationProvides communication• • Lightning short circuit damageLightning short circuit damage• • Installation requires long term Installation requires long term

outageoutage• • ExpensiveExpensive• • Superior performanceSuperior performance

ADSS F.OADSS F.O

ADSS (all dielectric self supporting) whichADSS (all dielectric self supporting) which

is mounted at various locations, typically 3is mounted at various locations, typically 3

to 10 meters below the phase conductorsto 10 meters below the phase conductors.. ADSS costs less than OPGWADSS costs less than OPGW Higher fiber count than Wrap type.Higher fiber count than Wrap type. Can be installed on towers not designed for Can be installed on towers not designed for

shield wires.shield wires. Suitable for hot line installationSuitable for hot line installation

WRAP AROUND F.OWRAP AROUND F.O

Wrap-type which is wound around Wrap-type which is wound around shield wires and, in some shield wires and, in some instances, around energized instances, around energized conductorsconductors

Hot-line installation is difficultHot-line installation is difficult Cost more than ADSS, but less Cost more than ADSS, but less

than OPGWthan OPGW Need a shield wireNeed a shield wire No operation problem is observedNo operation problem is observed

OPGW

WRAP

ADSS

OVERHEAD CABLES FOR OVERHEAD CABLES FOR POWER UTILITIESPOWER UTILITIES

OPGW ADSS WRAP AROUND

AL STRANDAL COATED STEEL STRAND

AL TUBE

XLPE SHEATH

POLYESTER TAPE

MOISTURE BLOCKING COMPOUND

AERIAL OPTICAL FIBRE CABLES

FIBRESTRENGTH MEMBERS

LOOSE TUBE

AD\AS\RKG\JP\FIBCROSS

FIBRE OPTIC CABLE INSTALLATION

OPGW

WRAP AROUND

ADSS

AD\AS\RKG\JP\FIBINST

SATELLITE COMMUNICATIONSATELLITE COMMUNICATION

A geostationary satellite is A geostationary satellite is used as an active used as an active repeater.repeater.

Modulated signals are Modulated signals are send from earth VSATs in send from earth VSATs in 6 GHz band to the 6 GHz band to the satellite.satellite.

Signals are beamed back Signals are beamed back to earth in 4 GHz band.to earth in 4 GHz band.

Roundtime propagation Roundtime propagation delay of 540ms existsdelay of 540ms exists

Communication is Communication is interrupted during interrupted during eclipses.eclipses.

Lingasugur

WRLDC Borivalli Vav Haldarwa JambuvaGotriSLDC Asoj

Itarsi

IndoreSub-LDC

ItarsiV’chalKorba STPP

RaipurBhilai-400(SLDC)

Jabalpur-400

Asoj

WRTCC

Indore

Dhule

VindhyanchalChandrapurPhadge

Kal

wa

Tarapur 1&2

Itarsi-220

Bina-400 Bho

pal-

400

Sub

-LD

C

Sat

na-2

20

Kat

ni-2

20

Jaba

lpur

-220

SLDC-Jabalpur

Korba-West

Korba-East

Kalwa

Kawas

Rajgarh

Khandwa

Sipat

Raigarh

Bhatapara

Seoni

Bhilai-220

Vadodara POP

Gandhar

Kakrapar

Dehgam

Tarapur 3&4

Phadge

Bhadrawati

Satna

Bina

Gwalior

VapiBoiser

LEGENDSGreen - ULDC Wideband LinkBLUE - PDT Link

Black - PLCC Link

Main Data PLCC Channel

St. By Data PLCC Channel

Both Main and Std. By Data PLCC Channel

Haldarwa Jambuva Asoj

62 Nos. PLCC Equipment109 Nos. Wideband ULDC Eqpt

MPSEB Sector

CSEB Sector

CSEB Sector

GEB Sector

WR-SC&C Communication system

ILA-387

ILA-174

ILA-311

ILA-194ILA-362 ILA-702ILA-368

KR-13RaipurB’Vati

SEB’s Wideband Equipment and OFC

OPGWU/G – OFC

SLDC GOA

Leased Link

PondaMapusa

Sembatti

Madurai 400

Trichy 400

Paramakudi Samayapuram Madurai North

Kodayar PH2

MaduraiSub LDC

Karaikudi

Tanjore 230

S R PudurPariyar PH

Theni Kayathar E

Sathur

TTPS

Podukotta C

Echengodu

Adanakottai

Peramballur

Kovilvenni

Pugalur

Thiruvarur

Tuticorin Auto

Trichy 230

Chennai Sub-LDC

(NLC TS-I)

Erode Sub-LDC(Erode)

Wideband Channel Routing for Madurai Sub-LDC

OrthonaduSivagangai

Existing RTU – 9 nos.

Existing RTU integrated

New RTUs – 13 nos.

PLCC Link

MW Link

ChalakudyT. NorthKozhikode -BKannur-B

Kalamassery

PallomKayamkulamKundraParipallyTrivendrumNorth

VidyuthiBhavanam

RSCC,Bangalore (Udumalpet)

Wideband Routing from Sub-LDC to SLDC,(Kalamassery)COMMUNICATION NETWORK FOR KERALA

MW Link

FO Link