1. PLCC SYSTEM by P.R.MEKAP Asst.Engineer SLDC,BBSR
GRIDCO POWER TRAINING CENTRE
“PLCC system” presented by P R Mekap (Tel) SLDC

2. “PLCC system” presented by P R Mekap (Tel) SLDC
Part -I
Overview
of PLCC Systems
“PLCC system” presented by P R Mekap (Tel) SLDC

3. Typical PLCC Installation
MS = Master station
PAX = Private automatic exchange
PR = Protection relay
PC = Computer
M = Modem F A WT C X PR PC MS
PAX
FAX M
RTU
PR= Protection relay
FAX = Facsimile equipment
M = Modem
RTU = Remote terminal unit cc
Shown above both stations, Master and Remote stations in one slide.
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

4. “PLCC system” presented by P R Mekap (Tel) SLDC
Topics to be discussed
1.Why PLCC is preferred in by Power Utilities?
2. What is the RF power and frequency band in PLCC?
3. Typical PLCC installation; how speech, data and protection commands are transmitted over PLCC system ?
4. PLCC link design, factors affecting performance of a PLCC link, effect of corona noise in PLCC .
5.Features of digital PLCC.
“PLCC system” presented by P R Mekap (Tel) SLDC

5. “PLCC system” presented by P R Mekap (Tel) SLDC
System description
PLCC is used in all power utilities as a primary communication service to transmit speech, telemetry and protection tripping commands.
PLCC system uses the HV power transmission line of the utility as a metallic medium for telecommunication. No need for laying separate telephone lines on the electric poles or hire lease lines from public telephone companies.
This is very economic, dependable and secure communication compared to any other means like HF wireless,VSAT or lease line. Cheaper than microwave radio and optical fibre. PLCC communication is feasible for line length up to 800 kM .
“PLCC system” presented by P R Mekap (Tel) SLDC

6. “PLCC system” presented by P R Mekap (Tel) SLDC
The frequency band used for PLCC is kHz. Type of modulation adopted is SSB-SC as per IEC-495 specification. PLCC channel carrying voice and super imposed data has gross band width of 4kHz.
RF out put power of a PLCC transmitter is 20/40/80W depending on distance. The radio frequencies used by the power utilities for PLCC should be approved by WPC, New Delhi, Ministry of Communication Govt.of India. Government charges a licence fee for this communication too.
The RF out put of PLCC terminal is injected in to high voltage power line using a suitable high voltage HF coupling capacitor(4-10nF). Also HF traps ( 0.2 – 2mH) are inserted at both ends of the line.
“PLCC system” presented by P R Mekap (Tel) SLDC

7. “PLCC system” presented by P R Mekap (Tel) SLDC
H.V Line
Wave Trap
Coupling apacitor
Components of PLCC
PLCC Terminal Translates voice and data into Radio Freq. Carrier.
Coaxial cable
LMU
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

8. POWER FREQUENCY & CARRIER FREQUENCYWT
Power Line
(50Hz) CC
RF carrier
(40-500kHz)
PAX
RTU
Transmission line
PLCC TERMINAL
(ABB-ETL41)
“PLCC system” presented by P R Mekap (Tel) SLDC

9. Function of PLCC terminalAF RF IF
gain PA H A
R.F Signal
(40 to 500 kHz)
User Signal
(0 to 4 kHz)
Line Side
User Side
Frequency conversion : audio signals into radio spectrum and vice versa
Amplification : Sufficient RF power to compensate the line attenuation
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

10. “PLCC system” presented by P R Mekap (Tel) SLDC
Wave Trap function
kHz ( HF) : Blocked
WAVE Trap
Behind
The carrier signal is transmitted over Power Line to reach the opposite end
The carrier signal is blocked by line trap; not allowed to enter inside the switch- yard
Front
Coupling
Capacitor
Transformer(s)
BusBar
Line Matching
Unit
Coaxial
PLC terminal
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

11. 50 Hz (Power Freq): through pass
Wave trap function
50 Hz (Power Freq): through pass
HV Line
Power energy
PLC Signal
Substation
Line Trap = High Impedance for PLC signal
Low Impedance for Power energy
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

12. Wave Traps Mounting Options
Vertical Pedestal
Horizontal Pedestal
Suspension
“PLCC system” presented by P R Mekap (Tel) SLDC

13. Wave Trap is a Band Stop filter (50-500kHz)
Inductance of
main Coil
Series
resistance
Lightning
Arrester
Tuning
Capacitor
Damped single
Line Trap
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

14. “PLCC system” presented by P R Mekap (Tel) SLDC
Wave Trap assembly
Corona ring
Lifting
lug
Terminal
Main
coil
Tuning device
Pedestal
Protective device
Tie rod
“PLCC system” presented by P R Mekap (Tel) SLDC

15. Capacitive Voltage Transformer ( CVT )
“PLCC system” presented by P R Mekap (Tel) SLDC

16. “PLCC system” presented by P R Mekap (Tel) SLDC
8800 pf
20mH Drain coil
DISCONNECT THIS LINK
LMU
220kV
CVT
COAXIAL CABLE
CVT and HF connection HF
PLCC TERMINAL
“PLCC system” presented by P R Mekap (Tel) SLDC

17. LMU : Type-MCD-80, ABB make
“PLCC system” presented by P R Mekap (Tel) SLDC

18. “PLCC system” presented by P R Mekap (Tel) SLDC
Co-axial Cable
“PLCC system” presented by P R Mekap (Tel) SLDC

19. “PLCC system” presented by P R Mekap (Tel) SLDC
LMU function
LMU = impedance matching + high voltage Protection
To prevent dangerous potential on the PLCC connection
To match impedance of PLCC set with power Line impedance.
s/s
PLCC
LMU
Coaxial
Matching +
Protection
LMU
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

20. “PLCC system” presented by P R Mekap (Tel) SLDC
LMU functional blocks
Substation HV
-line
Wave
trap
PLCC
Panel
Coupling
capacitor Tx or
Coax cable Rx
ABB MCD 80
“PLCC system” presented by P R Mekap (Tel) SLDC

21. ABB- MCD 80 internal wiring
Coax
To PLCC
CVT Z Z1 A G K L H 1
25ž
75ž M N O 2 3 P Q R B C C1 E T L2 L1 T1 F1 D F C2 C3 C4 Z2 Q1 LA
E.S
Drain
Coil
Match
Trans
“PLCC system” presented by P R Mekap (Tel) SLDC

22. Built in protection devices of LMU
Drainage coil to sink the leakage currents from CC/CVT to ground.
Lightning arrester across the CVT HF terminals and ground for transients protection.
Earth switch for grounding of CVT HF terminal during maintenance.
RF Transformer for galvanic isolation between power line and PLCC terminal.
“PLCC system” presented by P R Mekap (Tel) SLDC

23. “PLCC system” presented by P R Mekap (Tel) SLDC
HF Coupling modes Cc
LMDU
LMU
PLC LT
LMU Cc LT
PLC Cc
LMDU
LMU
PLC LT
Phase-to-Ground
Inter circuit
Phase-to-Phase
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

24. “PLCC system” presented by P R Mekap (Tel) SLDC
Part -II
PLCC
Link Design
“PLCC system” presented by P R Mekap (Tel) SLDC

25. “PLCC system” presented by P R Mekap (Tel) SLDC
Line loss and Noise
Signal loss factors
Taping loss (effect of PLCC terminals in parallel)
Coaxial cable attenuation ( length of the cable)
Return loss ( improper line matching )
Coupling loss (LMU,CC, Wavetrap)
Modal coversion loss (effect of carrier current on conductors)
Line loss (type of tower, conductor type and line length)
Line loss (Bad Weather conditions; rain,frost)
Corona Noise( Swicth Yard equipments & line insulators)
White Noise ( semiconductor devices)
“PLCC system” presented by P R Mekap (Tel) SLDC

26. Loss due to Parallel Working of PLCC
Parallel working of several PLCC terminals results a loss of power due to loading of transmitters by each other. This depends on frequency spacing between adjacent transmitters . It is called tapping loss and it should not exceed 2dB.
TX Spacing
>12kHz
> 16kHz
1 db per additional equipment
0.5 dB per additional equipment
“PLCC system” presented by P R Mekap (Tel) SLDC

27. “PLCC system” presented by P R Mekap (Tel) SLDC
Co-axial cable Loss
The RF power through coaxial cable gets attenuated by 2 to 6 dB per kM of cable length depending on carrier frequency used.
Frequency (KHz)
Attenuation(dB/km) 10
1.2
100
2.5
200
3.2
300
3.9
400
4.8
500
5.5
“PLCC system” presented by P R Mekap (Tel) SLDC

28. Coupling to one Circuit
Modal conversion loss
Coupling
Single circuit Line
Double Circuit Line
Ph to Gnd
1.5 … 3.5 dB
Coupling to one Circuit
1 … 3.5 dB
Ph to Ph
0.5 …1 dB
0.5 dB
Inter Circuit
---
0 dB
While RF power is directly coupled to one or two phase conductor(s) carrier current flows on all the three or six phase conductors running parallel. Depending on coupling methods used, the magnitude and direction of carrier current in each conductor is different. In an unfavorable mode the effect is equivalent to loss of transmit power up to 3.5dB = ac
“PLCC system” presented by P R Mekap (Tel) SLDC

29. Carrier signal attenuation per mile of line length
Attenuation in db/mile depends on conductor size, spacing above ground, transpositions, type of coupling and carrier frequency.
It also varies periodically with weather conditions (rain and frost do affect)
“PLCC system” presented by P R Mekap (Tel) SLDC

30. Line attenuation per Km = α
It is the attenuation of transmit power over a line length of one kilo meter = α db + f n d . 10
0.071 3 - a
bundle in
conductor
phase of
number
(mm)
diameter
(kHz)
frequency = n d f
“PLCC system” presented by P R Mekap (Tel) SLDC

31. Source of RF Noise is HV line
Corona Noise = 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)
Impulsive Noise = Caused by atmospheric discharges, breakers and isolator close/open operation
“PLCC system” presented by P R Mekap (Tel) SLDC

32. “PLCC system” presented by P R Mekap (Tel) SLDC
Corona Noise
Voltage (kV)
Correction (dB)
132
- 4
220
400
+ 4
500
+ 5
Bad weather Noise
Typical average Noise on a 220 kV line
and for a 3 kHz Bandwidth
“PLCC system” presented by P R Mekap (Tel) SLDC

33. Effect of bad weather on PLCC links
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 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.
“PLCC system” presented by P R Mekap (Tel) SLDC

34. Additional loss
Depending upon line configuration , mode of coupling and number of transpositions an additional loss is considered = aadd
Coupling arragement
IEC 60663
Number of transpositions 1 2
> 2
single circuit,Ph- Gnd
Centre only ( +++) 6
3 to 8 -
single circuit , Ph- Gnd
Centre or top
0 to 3
6 to 12
single circuit, Ph- Ph
Center to outer( +++)
0 to 5
8 to 12
2 to 10
single circuit , Ph- Ph
Centre to top
4 to 8
Double circuit, IC
Centre to centre
Double circuit, double -
Differential,Centre to top
0 to 1
0 to 4
2 to 8
“PLCC system” presented by P R Mekap (Tel) SLDC

35. Channel Band Width and White Noise
The noise power is proportional to noise band width of the channel. Noise bandwidth of 50 Baud voice frequency telegraphy channel is taken to be 80Hz and speech has band width of 2100Hz (300Hz-2400Hz)
Noise power in a 50Bd VFT channel is calculated as follows =10 log (2100Hz/80Hz) = -14dB
Meaning , Noise power in 50 Bd/80 Hz data channel is 14 dB below the noise power in Hz speech channel.
In the AF mixer of the transmitter, the input signal levels for test tone, pilot tone, speech and telemetry are kept proportionate to their noise band width to maintain same SNR at the receiver. This is discussed under channel loading in next slide.
“PLCC system” presented by P R Mekap (Tel) SLDC

36. Channel Loading PUNCOM PLCC
The scheme for allocating the weights to voice and data channels is based on the noise bandwidth of each channel
Speech( Hz)
2100/80
= 5.0
Pilot(3923Hz) = 50 baud
80/80
= 1.0
Signalling(3825Hz) = 50 baud
80/80
= 1.0
200baud FSK channel
360/80
= 2.12
300baud FSK channel
480/80
= 2.45
600baud FSK channel
960/80
= 3.55
1200baud FSK channel
Same as speech
= 5.0
Speech with 3 dB safety margin= 2 x 5 = 7
“PLCC system” presented by P R Mekap (Tel) SLDC

37. Channel loading (ABB PLCC)
AF signal
Signal Level assigned
Considering noise power
Voltage Weighting
ETL Test Tone 0.3/0.8/1KHz
-10dbu (Normal speech level) 1
ETL Pilot tone (3780Hz)
-16dBu ( 6dB below TT)
( -24dBu in ETI version)
0.5
Speech (safety margin=2)
-7dBu ( 3 dB above TT)
1.41
50 Bd data
-24dBu ( 14 dB below TT)
0.2
100 Bd data
-21dBu ( 3 dB above 50Bd)
0.28
200Bd data
-18dBu ( 3 dB above 100Bd)
0.4
600Bd data
-13dBu (6 dB above 200Bd)
0.71
1200 Bd data above speech
-13dBu (same as 600Bd data)
“PLCC system” presented by P R Mekap (Tel) SLDC

38. Signal Levels ( PUNCOM)
Speech ( with 9dB safety margin = 23 dB above reference)
Peak Envelope Power
additional 9 dB as safety margin leads to difference in SNR level for speech vs data in link budget calculation.
9 dB
14 dB above reference
1kHz Test tone
14 dB
600 Bd
data
10. 5 dB above reference
300 Bd
data
6 dB above reference
50 Bd
data
23dBm MAX
Pilot (50 Bd) as reference Level
PUNCOM Pilot/signaling
“PLCC system” presented by P R Mekap (Tel) SLDC

39. Signal weighting and absolute levels (PUNCOM)
VF Signals
Signal Levels
Absolute Level at HF Output
Absolute Level at input of Channel Modem
dBm0
Weighting
dBm
Speech( Hz) 5
+37
-16
Speech with 3dB safety margin +3 7
+40
-13
Pilot(3923Hz)
-14 1
+23
-30
Signalling(3825Hz)
200baud Channel -8 2
+29
-24
300baud Channel -6
2.45
+31
-22
600baud Channel -3
3.55
+34
-19
1200baud Channel
“PLCC system” presented by P R Mekap (Tel) SLDC

40. “PLCC system” presented by P R Mekap (Tel) SLDC
PLCC Link Budget
It is a mathematical model representing the performance of the proposed PLCC link for the given transmit power and carrier frequency.
Propagation parameters like line attenuation, modal conversion loss, coupling loss, corona noise and many other factors affecting signal quality are being considered in calculating link budget.
Finally we arrive at the SNR value for the voice and data channels. SNR is expected to be higher than 45dB A link is not at all feasible if SNR is less than 15dB.
“PLCC system” presented by P R Mekap (Tel) SLDC

41. Sample Link Budget : Boinda–Angul Puncom PLCC
“PLCC system” presented by P R Mekap (Tel) SLDC

42. Attenuation Constant - Alpha1 Power allocation for data P
Modal Conversion Loss - A c
(dB) 1
Additional Loss - A
add
(dB) 6
= *LOG(1700/4000)
Corona Noise for Speech - P
cor
(dBm)
Corona Noise for Data - Pcor (dBm)
Channel # 1
= *LOG(320/4000)
Coupling Loss - A
coupl
(dB) 6
= 0.71{SQRT(364/1)/21}+364/1000
Attenuation Constant - Alpha1
Line Attenuation - A
line
(dB)
= alpha1*40km +2*1+6
Signal level of reference channel Pr (dBm)
PEP – power[speech+data+pilot+signal ]
Power allocation for speech Psp (dBm) 1
23 dB above reference
Power allocation for data P
(dBm)
data
6 dB above reference
SNR (speech) in dB
58.30
Difference in two SNR level, because of 9 dB safety margin in speech
SNR (data) in dB
48.56
SNR>45dB
“PLCC system” presented by P R Mekap (Tel) SLDC

43. “PLCC system” presented by P R Mekap (Tel) SLDC
SNR Calculation
1 - Corona Noise for speech ( Hz) = log (1700/4000) = dB
2 - Corona Noise for 300 Bd data (320 Hz) = log (320/4000) = dB
3 – Attenuation Constant (364kHz;21 mm) = {(364/1)/21} +364/1000 = dB
4 – Line attenuation (40 kM) = (40 x dB) + 2x = dB
5 - Signal level of reference channel Pr (50 Bd) = PEP – power[speech+data+pilot+signal] = 43dBm – 10 log [ (1700/80) +  (320/80) +  (80/80) +  (80/80)] 2
= dBm
6 - Power allocation for speech Psp = 23 dB above reference = = dBm
7 - Power allocation for data Pdata = 6 dB above reference = = dBm
8- SNR (speech) = (Psp– coupling loss– line attenuation) - corona noise for spech
= (-33.7) = 58 dB
8- SNR (data) = (Pdata– coupling loss– line attenuation) - corona noise for data
= ( ) = 49 dB
Remarks : 20W PLCC operating at 320 KHz carrying speech plus data in Boinda - Angul 132 kV line (40km) gives acceptable SNR
“PLCC system” presented by P R Mekap (Tel) SLDC

44. “PLCC system” presented by P R Mekap (Tel) SLDC
Part -III
PLCC Equipments
ABB ETL series
“PLCC system” presented by P R Mekap (Tel) SLDC

45. PLCC Panel ( type: ABB ETL 41/42)
Modules
Cabinet
“PLCC system” presented by P R Mekap (Tel) SLDC

46. ABB PLCC terminal ETL- 41 System data -- complies to IEC 495
Operating mode : Single side band Suppressed carrier
Frequency range: 40 to 500kHz (programmable in 4 kHz Steps)
AF Bandwidth: 4 kHz (Speech band=300 – 3400 Hz)
Transmitter RF output power : 40W ( +46 dBm)
Spurious suppression > 60 dB
Pilot channel : Hz
Receiver RF sensitivity : dBm
Receiver Selectivity : 70dB ( 300Hz from band limit)
Receiver Image rejection > 80 dB
Receiver IF rejection > 80 dB
“PLCC system” presented by P R Mekap (Tel) SLDC

47. Functional blocks of a ABB ETL41 PLCC terminal
Basic equipment
AF Interfaces
B5LA,B4LA
Power Amplifier
+12V
-12V
+ 5V
Main
Power
Supply
Voice
interface
P4LB=AF CONV
P1LA
E5LA
16-20KHZ SA MO MO MO PA
P4LC
P4LF H
0-4kHZ
P4LG
Data
interface
P3LB dB DE DE DE DE
P3LB
P4LC
P4LD
PILOT
P4LB = AF CONV
P4LC =IF CONV.
P4LD= RX RF CONV
P4LF=TX RF CONV
P4LG = CARR GEN
P1LA = POW AMP
P3LB = RF HYB
MO=Modulator DE = Demodulator SA = Summing Amplifier
PA= Power Amplifier H = RF-Hybrid
“PLCC system” presented by P R Mekap (Tel) SLDC

48. speech + data + protection
ETL 41 module layout
speech + data + protection
B5LA Power Supply
48 VDC
P3LB
RF-Hybrid
Power amplifier
40 W
E5LA/B Tx-Filter
Power shelf
P7LA
Channel 1
O4LATelcontrol interf.
O4LC 4-wirePAXintrf.
P4LB AF-converter
P4LA Pilot+Supervn
P4LC IF-converter
G4AE Modem NSK5
P4LD Rx-converter
P4LF Tx--RF-conv.
P4LG Carrier synth.
B4LA DC-converter
G4AA DSP-Module
Channel shelf
P7LB
G4AC Interface 9R 4R 6R 6R 7R 6R 6R 4R 4R 8R
10R 8R 6R
NSD 50
User interface
basic
Power shelf
“PLCC system” presented by P R Mekap (Tel) SLDC

49. ABB_ETL 41: Modulation Scheme ( double conversion)
AF Band
IF range (low)
PLCC BAND (40 –500kHz)
IF range (high)
0-4Khz AF
IF1 Carrier =16kHz
IF1=16-20k
IF2 Carr =640kHz
3 modulators 2 stage IF
IF2= K
SSB-SC
TX FC= 724 kHz ( Programmable)
TX=
“PLCC system” presented by P R Mekap (Tel) SLDC

50. ABB_ETL 41: Demodulation Scheme (Triple conversion)
AF Band
IF range (low)
PLCC BAND (40 –500kHz)
IF range (high)
RX= KHz
SSB-SC
4 demodulators
3 stage IF
IF3=
RX FC = 728 kHz (programmable)
IF2=
IF3 Carr =480kHz
IF1 Carrier =16kHz
IF2 Carr =160kHz
AF=0-4Khz
IF1=16-20K
“PLCC system” presented by P R Mekap (Tel) SLDC

51. Multiplexing speech, telemetry and tele protection
Programmable
speech bandwidth
Speech 3.4 kHz
Speech 3.2 kHz
Speech 3.0 kHz
Speech 2.8 kHz
Speech 2.6 kHz
Speech 2.4 kHz
Speech 2.2 kHz
Speech 2.0 kHz
plus
0.3
3.6
4.0
kHz
tele protection
(4 trip commands)
0.3
2.0
3.6
4.0
kHz
plus
50 Bd
Speed
100 Bd
Data/Tele metering
(FSK signal)
200 Bd
300 Bd
Center frequency
120 Hz steps
600 Bd
1200 Bd
2400 Bd
0.3
3.6
4.0
kHz
“PLCC system” presented by P R Mekap (Tel) SLDC

52. Data Communication over PLCC link
FSK PRINCIPLE
Frequency shift keying
PLCC
digital
analog
Input digital
Output analog
MODEM
Bit 0 = f1
Bit 1 = f2
Analog Output
f1, f 2
YOUR NOTES:
Digital Input
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

53. PROGRAMMING steps WITH NSK5
Super Imposed Data channel (SID)
2220Hz
 60 ( BW=120Hz)
2760Hz
 480( BW=960Hz)
600 Bd
50 Bd
SPEECH O
2160 fc
2280
2280
3240
2KHZ fc
PROGRAMMING steps WITH NSK5
1. Baud rate
2. Frequency TX
3. TX level of Modem
4. Tx level of PLCC
5. Impedance Matching with PLCC
YOUR NOTES:
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

54. Tele protection architecture
Substation A
Substation B
HV-line
Protection Relay
Protection System
Tele- protection Equipment
Teleprotection System
Physical Link
Telecommunication
System
A teleprotection equipment is:
Interface between protection relay and telecommunication circuit / system
Converts the signal from the protection relay into a signal suitable for transmission over a telecommunication link
MODULATION (analog channels)
CODING (digital channels)
Multiplexes several signals into one telecom channel
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

55. “PLCC system” presented by P R Mekap (Tel) SLDC
NSD-50 Plug in protection coupler with ETL-41 PLCC
Signals:
"AL" Common alarm (red) This LED lights on all the units that the alarm concerns.
"RDY" Ready (green) The "transceiver ready" signal (TRY)
"TRP" Trip (green) The tripping signal has picked up.
"GRD" Guard (green) Lights whenever the guard signal is being received.
"SNR" Signal-to-noise ratio (red) Lights whenever the signal-to-noise ration is too low.
"LEV" Level alarm (red) The signal strength of the guard signal is not within the permissible limits.
"TxA" ..."TxD" (green) Lights whilst the corresponding signal is being transmitted.
"RxA" ..."RxD" (green) Lights whilst the corresponding signal is being received.
"TxA/B", "TxC/D" (7 segment display) The number of commands transmitted is displayed (00 ... 99).
"RxA/B", "RxC/D" (7 segment display) The number of commands received is displayed (00 ... 99).
“PLCC system” presented by P R Mekap (Tel) SLDC

56. “PLCC system” presented by P R Mekap (Tel) SLDC
Digital PLCC ABB ETL 500
Immune to noise
High speed data
Secured teleprotection
HMI
“PLCC system” presented by P R Mekap (Tel) SLDC

57. Data AMX + Teleprotection
ETL500 Versions with AMX500
Data
AMX
10…12.8 kbit/s
Speech + Teleprotection
Pilot
ETL580 4kHz
ETL540 4kHz
ETL505 4kHz
4 kHz
4 kHz
Pilot
Data AMX
22 … 28.8 kbit/s
ETL580 4kHz
ETL540 4kHz
ETL505 4kHz
4 kHz
Speech + Teleprotection
Data NSK
Pilot 2*
ETL580 8kHz
ETL540 8kHz
8 kHz
Pilot
Data AMX + Teleprotection
40 … 64 kbit/s
Three examples illustrate possible ways of using a given frequency band and demonstrate the versatility of the ETL500 system:
ETL540/1*4kHz. When using ETL500 single channel equipment the capacity can be considerably enhanced by adding the AMX500 unit. A possible configuration is illustrated. This arrangement permits a data channel with a transmission rate of 4800 bit/s to be superimposed above the speech channel; which, in addition, contains the in-band tones for protection signalling.
ETL540/2*4kHz. ETL500 double channel equipment, occupying 8 kHz bandwidth. With this configuration one channel may be exploited for operational speech combined with teleprotection and low speed data for SCADA application, whereas the other channel may convey high speed data and several compressed speech channels.
ETL540/1*8kHz. Example shows an ETL500 single channel equipment requiring the same 8 kHz band but this is configured to work in high speed mode using the entire bandwidth. With this configuration a transmission rate up to 64 kHz may be obtained under favourable line conditions. A possible subdivision of the available capacity among different services may be as follows:
2 speech channels/ 1 data channels 19.2 kBit/s synchronous/ 3 data channels Bit/s asynchronous.
Optimum performance of the teleprotection service is ensured by the NSD550 which operates entirely independenty of the AMX500 unit.
“PLCC system” presented by P R Mekap (Tel) SLDC
PLCC OVERVIEW/P.R.MEKAP

58. Digital PLCC – latest version
ABB ETL-600
HMI
“PLCC system” presented by P R Mekap (Tel) SLDC

59. Digital PLCC ETL 600 -Technical data
“PLCC system” presented by P R Mekap (Tel) SLDC

60. Digital PLCC : ETL600 (256kbps data)
“PLCC system” presented by P R Mekap (Tel) SLDC

61. Digital PLCC – ETL600 (secured teleprotection)
“PLCC system” presented by P R Mekap (Tel) SLDC

62. “PLCC system” presented by P R Mekap (Tel) SLDC
Part -IV
PLCC
Test & measurements
“PLCC system” presented by P R Mekap (Tel) SLDC

63. “PLCC system” presented by P R Mekap (Tel) SLDC
Test Instruments for PLCC
Selective Level Meter
“PLCC system” presented by P R Mekap (Tel) SLDC

64. Selective Level Generator
Test Instruments for PLCC
Selective Level Generator
“PLCC system” presented by P R Mekap (Tel) SLDC