fundamental of power line carrier communication

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University
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1
January
07,
Markus
Vogt,
PS
BTN
Fundamentals of
Power Line Carrier
Course CHT568
ETL600
Operation&Maintenance

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2 Chapter Overview
This Chapter Covers the Areas
n PLC-Components:
n PLC-System
n Coupling Units

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3
PLC
ETL
PLC
ETL
Power Line
Private Cable
Leased PTT Line
(e.g. AF Cable)
Port 1
Port 2
Port 3
Port 4
Port 6
Port 5
Port 1
Port 2
Port 3
Port 4
Port 6
Port 5
Optical Fibre
Transmission
Medium
Radio Link
Strengths
Protection
Voice
Data
Protection
Voice
Data
Weaknesses
Range of Available Systems

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Substation A
HV-line
eg. 220KV/50Hz
Transport of electrical energy
Substation B
Transmission of data, speech and protection signal
PLC-
Terminal
ETL600
PLC-
Terminal
ETL600
LT LT
CC/CVT CC/CVT
Coupling
device
LMU
RF 24-1000kHz RF 24-1000kHz
Coupling
device
LMU
Abbreviations: LT-Line Trap, CC-Coupling Capacitor, CVT-Capacitive Voltage Transformer, HV-High Voltage, LMU-Line Matching Unit
Components of a PLC Link
analog/digital
nx 300-3720Hz
analog/digital
nx 300-3720Hz

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5 Attenuation on Homogeneous Line

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6 Line Traps, Type DLTC

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7 Usage of PLC Line Traps (II)
n PLC-signal transmission demands:
n HF-blocking elements (e.g. PLC Line Traps) are needed at both
coupling points
n to ensure defined impedance conditions independent from switching
condition of the substation
n to prevent undue loss of carrier signal into the substation
n to block HF-signals from other sections of the power grid to reuse
RF- frequency bands
n Energy transportation demands:
n HF-blocking elements must be of very low impedance at power
frequency and must satisfy all power frequency current demands

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8 Line Traps

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9 DLTC Production Range
IN(A) Standard IkN(kA) Ikm(kA) Inductance LtN(mH)
400 IEC1 10 25.5 0.2 0.315 0.5 1.0 2.0
IEC2 16 41 0.2 0.315 0.5 1.0 2.0
ANSI 15 38.5 0.2 0.315 0.5 1.0 2.0
630 IEC1 16 41 0.2 0.315 0.5 1.0 2.0
IEC2 20 51 0.2 0.315 0.5 1.0 2.0
800 IEC1 20 51 0.2 0.315 0.5 1.0 2.0
IEC2 25 64 0.2 0.315 0.5 1.0 2.0
ANSI 20 51 0.2 0.315 0.5 1.0 2.0
1000 IEC1 25 64 0.2 0.315 0.5 1.0 2.0
IEC2 31.5 80.5 0.2 0.315 0.5 1.0 2.0
1250 IEC1 31.5 80.5 0.2 0.315 0.5 1.0 2.0
IEC2 40 102 0.2 0.315 0.5 1.0 2.0
ANSI 36 92 0.2 0.315 0.5 1.0 2.0
1600 IEC1 40 102 0.2 0.315 0.5 1.0 2.0
IEC2 50 128 0.2 0.315 0.5 1.0 2.0
ANSI 44 112 0.2 0.315 0.5 1.0 2.0
2000 IEC1 40 102 0.2 0.315 0.5 1.0 2.0
IEC2 50 128 0.2 0.315 0.5 1.0 2.0
ANSI 63 161 0.2 0.315 0.5 1.0 2.0
2500 IEC1 40 102 0.2 0.315 0.5 1.0 2.0
IEC2 50 128 0.2 0.315 0.5 1.0 2.0
3150 IEC1 40 102 0.2 0.315 0.5 1.0 2.0
IEC2 50 128 0.2 0.315 0.5 1.0 2.0
ANSI 63 161 0.2 0.315 0.5 1.0 2.0
4000 IEC1 63 161 0.2 0.315 0.5 1.0 2.0
IEC2 80 204 0.2 0.315 0.5 1.0 2.0
ANSI 80 204 0.2 0.315 0.5 1.0 2.0
and various types to fulfill special customer demands

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n Maximum system voltage Um
n Rated power frequency fpN (50 Hz, 60 Hz)
n Nominal current IN (RMS)
n Short-time current IkN (RMS) (acc. IEC1, IEC2 or ANSI)
n Desired band limit frequencies f1/f2
n Rated blocking impedance (R - trap or Z - trap)
n Coupling method and type of line conductor
Required determinativ parameters:
Example Short time current:
Nominal current: 400 A
Short-time current IEC1: 10 kA
Short-time current IEC2: 16 kA
Short-time current ANSI: 15 kA
How to Choose a Line Trap

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n Min. required (Rated) blocking impedance
If coupling method and type of line
conductor is given select:
600 Ohm
600 Ohm
400 Ohm
400 Ohm
Required
blocking
impedance
350...400 Ohm
350...400 Ohm
280...300 Ohm
280...300 Ohm
Line
impedance
Single
Single
Bundle
(>220 kV)
Bundle
(>220 kV)
Type of
conductor
Phase to
ground
Phase to
phase
Phase to
ground
Phase to
phase
Coupling
method
How to Choose a Line Trap

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12 Impedance of Line Trap
0 50 100 150 200 250 300
1000
800
600
400
200
0
Blocking
impedance,
-resistance
Frequency [kHz]
Rated value
L1
Arrestor
L
C
R
Tuning Device
L1 = Main coil of line trap
C, L, R = Tuning device elements
Equivalent circuit diagram
7

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13 Band Limits
Lower band limit [kHz]
0 50 100 150 200
0
100
200
300
400
500
1.0 mH
0.5 mH 0.315 mH
2.0 mH
0.2 mH
Upper
band
limit
[kHz]
Valid for blocking
resistance Rb > 400 Ohm
Band Tuned Line Traps Type DLTC

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14 Band Limits
Lower band limit [kHz]
0 50 100 150 200
0
100
200
300
400
500
Upper
band
limit
[kHz]
1.0 mH
0.5 mH 0.315 mH
2.0 mH
0.2 mH
250
Band Tuned Line Traps Type DLTC
Blocking resistance Rb> 600Ohm

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15 Flexible Mounting
Mounted on support
Suspended

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16 Coupling Capacitors & Capacitor Voltage Transformers

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17
CVD
Coupling Capacitor CC : CCA - - -
Capacitor Voltage Transformer CVT: - CPA CPB CPB
Elecromagnetic Unit EMU : - EOA EOB EOB
Capacitive Voltage Divider CVD : CSA CSA CSA CSB
EMU
Coupling Capacitors & Capacitor Voltage Transformers

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3‘500 pF
525 kV
CCA 550
4‘800 pF
420 kV
CCA 420
5‘300 pF
362 kV
CCA 362
6‘400 pF
300 kV
CCA 300
7‘600 pF
245 kV
CCA 245
10‘600 pF
170 kV
CCA 170
12‘700 pF
145 kV
CCA 145
14‘700 pF
123 kV
CCA 123
23‘800 pF
72.5 kV
CCA 72
Rated capacitance
System voltage
Type *
*As well valid for capacitor voltage transformer CPA
Standard capacitance:
Coupling Capacitors & Capacitor Voltage Transformers

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19
L= PLC connection point
A= OHL connection point
A‘=Protection and instrumentation conn.point
C1= capacitance for Prot.+Instr.
C1+C2=capacitance for PLC
Capacitor Voltage Transformer

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20 Modular Coupling Devices

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21 Modules of Coupling Equipment
n High-pass coupling filter A9BS
n High-pass coupling filter with hybrid transformer A9BT
n Band-pass coupling filter A9BP
n Band-pass coupling filter with hybrid transformer A9BR
n Attenuator A1AD
n Impedance transformer A1AE
n Separating filter A9CA
n Shunt tuning filter E9AA
n Hybrid Transformer A1AC

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22
Coupling
capacitor
Coupling
device
MCD 80
or
Line
trap
HV-line
Tx
PLC equipment
Cabinet
Rx
Substation
Coax cable
1) 2
2)
3)
5) 4)
6)
Principle of PLC Coupling

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23 Elements of Coupling Device
1) Surge arrester for transients protection at the primary terminals of
coupling device.
2) Drain coil for draining of power frequency currents 50/60 to earth.
3) Earthing switch for direct and efficient earthing of primary terminals.
4) Transformer for matching and galvanic isolation between primary
and secondary terminals of coupling device.
5) High-pass or band-pass filter elements for optimum matching.
6) Coaxial cable to PLC equipment in cabinet.

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24 Single Phase Coupling
HV-line
Substation
Coupling
capacitors
Tx
Rx
Coupling
device
MCD 80
Line
trap
Cabinet
PLC
equipment
A9BS or A9BP
Coax Cable

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25 Phase to Phase Coupling
n2 single phase coupling devices
nHybrid transformer for decoupling of signals
and generation of push-pull signals
HV-line
Substation
Coupling
capacitors
Tx
Rx
Coupling
devices
MCD 80
A9BS
or A9BP
A9BT or A9BR
Line
traps
Cabinet
PLC
equipment
Elements
Coax cable
Coax cable

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26 Carrier Combiner Unit A9BM
Z2
Z1
Z2
Z1
PLC
A9BM
(or A9CS
with A1AC)
Equipment
room
Phase to phase coupling with balanced hybrid in equipment room

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27 Three Phase Coupling (Mode 1)
n2 phase to phase coupling devices
n1 phase to ground coupling
HV-line
Substation
Coupling capacitors
Coupling
devices
MCD 80 A9BS
(A9BP)
A9BT
(A9BR)
Line traps
Coax cable
Elements
Tx
Rx
Cabinet
PLC
equipment
A9BT
(A9BR)
Coax cable
Coax cable

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28 High-Pass Coupling Device A9BS/A9BT
A G K L H 125ž
75ž
M N
O
1
2
3
P
Q R
B
C
C1
Z2
LE C
T
L2
L1
Z1
T1
CK
F1
D
E
F
Ck 1500 2200 2700 3300 3900 4700 5600 6800 7500
Z1 pF to to to to to to to to and
Ω 2199 2699 3299 3899 4699 5599 6799 7499 up
240 232 158 132 115 96 80 70 60 52
320 180 128 102 90 78 76 70 58 52
Lower frequency limit f1 [kHz]
Ck = coupling capacitance Upper frequency limit f2 = 500 [kHz]
Z1 = impedance of overhead line Z2 = equipment side impedance
C2
C3
C4
Z2
Q1

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29 Tuning Characteristics
High-Pass Coupling Filter A9BS/A9BT
Composite
loss Ac
and return
loss Ar
25
[dB]
20
15
0 100 200 300 400
Ac
600
[kHz]
10
5
0
Ar
Coupling capacitor Cc 4.7 nF Nominal line impedance Z1 240 Ω
Lower cut-off frequency F1 80 kHz Nominal return loss Ar 12 dB
Upper cut-off frequency F2 500 kHz Nominal composite loss Ac 2 dB

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30 Band-Pass Coupling Device A9BP/A9BR
Z2
Z1
CK
The attainable frequency
ranges can be calculated
f1
f2 =
1–
2.5 x 10–7 x π x f1 x Ck x Z1
Ck + 1.0 x 10–7
f1 = lower frequency limit [Hz]
f2 = upper frequency limit [Hz]
Ck = coupling capacitance [F]
Z1 = impedance
of overhead line [Ω]
Z2 = equipment
side impedance [Ω]
Formula is valid for 12dB return loss
Formula is valid for 12dB return loss
1

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31 Tuning Characteristics
Composite
loss Ac
and return
loss Ar
25
[dB]
20
15
38
Ac
70
[kHz]
10
5
0
Ar
F1 F2
Coupling capacitor Cc 4.7 nF Nominal line impedance Z1 240 Ω
Lower cut-off frequency F1 40 kHz Nominal return loss Ar 12 dB
Upper cut-off frequency F2 64 kHz Nominal composite loss Ac 2 dB
Band-Pass Coupling Filter A9BP/A9BR

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32 PLC Link
Z2
Z1
Z2
Z1
Ac
Substation A
Z2
Z1
Z2
Z1
PLC
Ac
At
At = Tapping loss of line trap
Ac = Composite loss of phase-phase coupling
Al = Composite loss of HV line
Acoax = Composite loss of coax cable
A = Overall attenuation of PLC link
Substation B
At
PLC
Al
Acoax Acoax

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33 PLC By-Pass Circuits
Straight through connection without local carrier equipment
Z2
Z1
Z2
Z1
Ac
At
At
Substation
Z2
Z1
Z2
Z1
Ac
At = Tapping loss of line trap
Ac = Composite loss of phase-phase coupling
Acoax = Composite loss of coax cable
A = Overall attenuation of by-passed signal
A = 4...8 dB
Acoax