PLCC: A promising futuristic technology!!!.. still in India we do not use it due to many reasons.... because PLCC, Power Line Carrier Communication, is an approach to utilize the existing power lines for the transmission of information.

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2. Contents
1. Communication Review
• Options
• Advantages - PLCC
2. PLCC Overview
• Phase to Ground system
• Phase to Phase system
• Functional block diagram
• Power System Communication-requirements
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3. Option for different power utility communication
• MICROWAVE
• UHF/VHF SYSTEMS
• RADIO LINK
• FIBRE OPTIC
• TELEPHONE CABLE
• POWER LINE CARRIER COMMUNICATION (PLCC)
Communication Overview
Atmospheric conditions,
High Capital Cost
Atmospheric conditions, high capital cost,
high maintenance
Congested frequency band
High cost for low traffic
Mechanically weaker,
High theft chances
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4. ADVANTAGES OF POWER LINE CARRIER
COMMUNICATION:--
• COMPACT
• RELIABLE
• COST EFFECTIVE FROM DISTANCE POINT OF VIEW
• ENTIRELY WITHIN POWER UTILITY’S CONTROL
• IMMUNITY FROM ATMOSPHERIC CHANGES
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5. 5
PLCC OVERVIEW
 PLCC system uses the same High Voltage transmission line connecting two sub-
stations for telecommunication purpose too.
 PLCC is used in all power utilities as a primary communication service to transmit
speech, telemetry and protection tripping commands. This is economic and reliable for
inter grid message transfer as well as low bit rate RTU signals.
 The voice/data are mixed with radio frequency carrier (40-500kHz), amplified to a level
of 10-80W RF power and injected in to high voltage power line using a suitable coupling
capacitor. The power line as a rigid long conductor parallel to ground, guides the
carrier waves to travel along the transmission line. Point to point communication takes
place between two SSB transceivers at both ends.

6. 6
BECAUSE OF LOW ATTENUATION IN THE RANGE 50-500kHz, HV
TRANSMISSION LINES ARE GOOD MEANS OF COMMUNICATING
INFORMATION.THE MAX RANGE OF PLC COMMUNICATION
CHANNEL OPERATING AT LOWER END (80kHz) CAN TRANSMIT
INFORMATION AS LONG AS 800KM WITHOUT REPEATERS

7. 7
TeleprotectionSpeechData / SCADA Telecom
Services
Voltage
[kV]
33
1,0
110
220
800
Fiberoptic
Microwave
Radio/CATV/Cable
Fiberoptic
Radio
Cable
NMS
PLC
Narrowband
PLC
0,23
50
Broadband FO/RAD

8. Power Line Carrier Systems
• Main applications:
--Multipurpose transmission means to cover the
operational needs of a power utility
• Operational telephone
• Low speed data (SCADA)
--Back-up systems for backbone channels carrying
important services
--Tributary link to wideband backbone systems
--Protection signaling
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9. Substation A
HV-line
Transport of electrical energy
Substation B
Transmission of data, speech and protection signal
PLC-
Terminal
PLC-
Terminal
LT LT
CC/CVT CC/CVT
Coupling
device
Coupling
device
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10. 10
PLC coupling components

11. Typical PLCC system
PLCC OVERVIEW
COUPLING
DEVICE
75 OHMS HF CO-
AXIAL CABLE
CARRIERS
WAVE TRAP / LINE TRAP
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12. 12
RF carrier
(40-500kHz)
Power Line
(50Hz)
LT
CC
PAX
RTU
PLCC TERMINAL
Power Line Carrier Communication System
Transmission line

13. 13
Typical PLCC system
CC blocks high
oltage 50Hz power
tering into the PLCC
terminal
BT & LMU
matches the
PLCC
terminal
impedance
to the line
impedance
Earth Coil, LA
are for
protections for
leakage
/surges and
earth switch
for
maintenance
purpose
Line trap blocks PLCC
signal entering into switch
yard equipment
PLCC OVERVIEW

14. 14
PLCC Terminal = Translates voice and data into High Frequency Carrier. Output Power =10 to 80W
LMU = Line Matching Unit = For impedance matching between line and coaxial cable, includes high
voltage protection devices like drainage coil(20mH), lightening arrestor(500V) and an earth switch.
Coupling Capacitor = Couples high frequency carrier with Power Line ( 4000 to10000pF)
Line Trap = Do not allow the transmitted HF carrier to enter inside the sub-station. (L = 0.5 to 2mH)
With out Line trap HF carrier get by-passed to some other line on the same bus bar and may leak
to ground ( a earth switch inside the yard provided for each bay is kept closed during maintenance)
H.V Line
LMU
Coupling
capacitor
Line Trap
PLCC
terminal
Coaxial
cable
Components

15. PLC Line Traps
Energy transportation demands:
-HF-blocking elements must be of very low impedance at
power frequency and must satisfy all power frequency
current demands.
PLC-signal transmission demands:
-HF-blocking elements (e.g. PLC Line Traps) are needed at
both coupling points
• to ensure defined impedance conditions
independent from switching condition of the
substation
• to prevent undue loss of carrier signal into the
substation
• to block HF-signals from other sections of the power
grid
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16. L1
Arrestor
L
C
R
Tuning Device
L1 = Main coil of line trap
C, L, R = Tuning device elements
Equivalent circuit diagram
Impedance of line trap
0 50 100 150 200 250 300
1000
800
600
400
200
0Blockingimpedance,-resistance
Frequency [kHz]
Rated value
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17. = PLC signal Blocking
HV Line
Substation
Line Trap = High Impedance for PLC signal
Low Impedance for Power energy
Power energy
PLC Signal
Line trap function
17

18. Corona ring
Lifting lug
Terminal
Main coil
Tuning device
Pedestal
Protective device
Tie rod
Line Trap Components
18

19. Inductance
of
main Coil
Lightning
Arrester
Series
resistance
Line Trap is a parallel LC circuit
19

20. • SA-Connected across the main coil and the tuning device to the LT
prevent from being damaged by transient overvoltages
• Tuning Device- To tune for the required frequency using suitable
capacitor in parallel with the inductance of the coil.
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21. 21

22. 22

23. Mounted on supportSuspended
23

24. 24

25. Conductor
Spacer rods
25

26. CVT : CAPACITIVE VOLTAGE TRANSFORMER
26

27. LMU
LMU
Coupling
Capacitor
Line Trap
PLC
Coaxial
s/s
LMU = impedance matching Transformer
+ high voltage Protection
 To prevent dangerous potential on the
PLCC connection
To match PLCC set & transmission Line
Matching + Protection
LMU function
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28. Coupling
capacitor
Coupling
device
consisting of
SA, Drain
Coil, Earth
switch,
Transformer
& Filter
or
Line
trap
HV -line
Tx
PLC equipment
Cabinet
Rx
Substation
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29. Surge arrester for transients protection at the primary
terminals of coupling device.
Drain coil for draining of power frequency currents to
earth.
Earthing switch for direct and efficient earthing of
primary terminals.
Transformer for matching and galvanic isolation between
primary and secondary terminals of coupling device.
High-pass or band-pass filter elements for optimum
matching.
Elements of Coupling Device
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30. HV-lineSubstation
Coupling
capacitors
Tx
Rx
Coupling
device
MCD 80
Line
trap
Cabinet
PLC
equipment
A9BS or A9BP
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31.  2 single phase coupling devices
 Hybrid transformer for decoupling of signals
and generation of push-pull signals
HV-lineSubstation
Coupling
capacitors
Tx
Rx
Coupling
devices
MCD 80
LMU
LMDU
Line
traps
Cabinet
PLC
equipment
Elements
31

32.  PHASE TO GROUND COUPLING
 PHASE TO PHASE COUPLING
 INTERCIRCUIT COUPLING
32

33. COUPLING
DEVICE
75 OHMS HF CO-
AXIAL CABLE
CARRIERS
33

34. Phase to Phase System
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35. STATION A
STATION B
LMU
LMDU LMDU
LMU
CARRIER CABINET CARRIER CABINET
LINE#1
LINE#2
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36. Inter circuit
Phase-to-Ground
LMU
Cc
LT
PLC
Cc
LMDU LMUPLC
Cc
LT
LT
Cc
LMDU LMUPLC
Cc
LT
LT
Phase-to-Phase
HF Coupling modes
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37. Translation : User audio signals into radio Spectrum
R.F Signal
(40 to 500 kHz)
User Side Line Side
User Signal
(0 to 4 kHz)
Amplification : To compensate the line attenuation
Function of PLCC terminal
AF RF
IF
IF
gain
AF
IF
IF
RF
RF
IF
AF
IF
PA
HH
A
H= hybrid
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38. USER INTER
FACES
MODEM
POWER
AMPLIFIER
LINE INTER-
FACES
POWER
SUPPLY
FREQUENCY
GENERATION
UNIT
CONTROL
UNIT
PLCC OVERVIEW
Functional Block diagram
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39. 39

40. 40
Speech 2.0 kHz
Speech 3.4 kHz
0.3 3.6 4.0
0.3 3.6 4.0
0.3 3.6 4.0
1200 Bd
300 Bd
Speed
Center frequency
120 Hz steps
2.0
Programmable
speech bandwidth
plus
tele protection
(4 trip commands)
plus
Tele metering
(FSK modem)
kHz
kHz
kHz
Multiplexing speech & data in 4 kHz raster
Speech 3.4 kHz

41. Typical PLCC Installation
MS = Master station
PAX = Private automatic exchange
PR = Protection relay
PC = Computer
M = Modem
ETLETL
LT
LT
C
FAX
FAX
PR PC MS PAX FAX
M
PR PC RTU FAX
M
PR= Protection relay
FAX = Facsimile equipment
M = Modem
RTU = Remote terminal unit
cc cc
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42. "Analog" PLC = Single Side Band PLC
--Baseband signal = analogue waveform
Speech, FSK data, tones
Frequency division multiplexing
--Baseband signal is 1:1 translated into RF band using
SSB techniques
--Realized either in:
“analogue” technology or in
digital technology (DSP)
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43. FSK
AF / RF
Conversion
RF
E & M Signalling
out of band signalling
Speech
+ inband signalling
(FAX)
Data
(anisochronous)
Teleprotection
Teleoperation
(Modem, FSK)
TDM-Mux/Demux
Service
Interface
RS232
Clock
Digital
Bus
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44.  Digital PLC
 Baseband signal = serial digital data
 Digitized speech, digital data
 Time division multiplexing
 Serial data translated into RF band using digital
modulation principles
 Realized almost entirely in digital "DSP"
technology
44

45. AF / RF
Conversion
RF
Teleprotection
Teleoperation
(Modem, FSK)
Service
Interface
RS232
Clock
TDM
MUX /
DEMUX
QAM
Modem
E & M
Speech
FAX
DATA
Cl
Digital
Bus
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46.  Increased capacity
 approx. 2.....3 times that of an SSB PLC
 Improved speech quality
 Narrowband solution
 fits into contiguous 8 kHz HF slots
 complies with existing coupling equipment
(LMU’s, CC’s/CVT’s and line traps)
 Provides potential for expandability for future digital
networks
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47.  Losses increase for all inclement weather conditions
 The worst offender is when heavy frost is formed on the line
 Because of the skin effect, the carrier signal tries to propagate on the
ice instead of the conductor.
 The attenuation can change as much as 4:1 depending on the
frequency.
 The contaminats (on the insulators) have a larger effect when it is raining
than when the line is dry.
 The worst condition is a light rain with the presence of contaminants on the
insulators
Effect of bad weather on PLCC communication
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48. RF noise in HV line  two mains effects
Impulsive Noise = Caused by atmospheric discharges, breakers
and isolator close/open operation
Corona effect = Due to sequences of pulse streams caused by arcs
over conductors. It appears during positive-going half-cycle of the
Line voltage (occurrance frequency for a 50Hz 3-phase system is 150
Hz)
The corona noise could be subject to considerable variations due to
differences in the design parameters of the overhead line.
Other variations are possible due to the construction, altitude and
age of the line
Weather effect can also be significant
RF Noise
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49. I. Limited carrier frequency spectrum (40 - 495 KHz)
 Less than 40 KHz - cost of coupling equipment (wave traps,
coupling units / CVTs) increases.
 More than 495 KHz - attenuation due to radiation of carrier
signal increases (OR) signal interference with other systems of
operation.
 495 KHz - 500 KHz is International Distress signal
 520 KHz onwards: Radio Broadcast Band
 Only 110 frequency pairs of 4 KHz band width are possible in
the given frequency range (40 - 495 KHz) and several factors
are to be considered before selecting a frequency pair.
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50. II. NOISE AND RADIO INTERFERENCE:
Sustained Noise (Random Noise) caused due to irregular discharges across
the insulators and conductors. This is called THE CORONA.
Typical common Noise levels are:
132 kV system : - 30 dBm
220 kV System : - 20 dBm
400 kV System : - 10 dBm
III. Impulse Noise: dBm Eq. Volts
Operation of isolators / breakers+20 to + 25 7.75 to 13.78
Short circuits + 30 24.51
Flashovers - 20 0.07
Atmospheric discharges +25 13.78
2W Input 0 0.775
S/N Ratio - 6 0.38
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51. IV. Interference due to neighboring systems
Radar beacons, aeronautical systems, broadcasting
service systems operating in MF / LF bands
International distress signal (495 - 500 kHz).
V.Reliability / Availability:
Reliability factor of Modern PLCC equipment is of the
order of 99.90 to 99.97%
Affected by attenuation, corona noise, impulse noise
and HV line availability.
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