This document provides an overview of power line carrier communication (PLCC). PLCC uses existing power lines to transmit speech, data, and teleprotection signals between electric substations over long distances at speeds up to 9.6Kbits/sec. It requires coupling devices like capacitors and line matching units to connect communication equipment to high voltage power lines safely. Wave traps are also used to prevent carrier currents from interfering with equipment in power stations. PLCC provides a cost-effective communication solution for power systems.

1. BY
A.MANOJ CHOWDARY
AM.EN.U4EEE12001
M.KIRAN NAYAK
AM.EN.U4EEE12128

2.  Introduction
 Basic principle of PLCC
 Specification
 Basic Arrangement
 Tuning capacitor
 Wave trap
 Types of coupling
 Battery charger
 Fault Traction
 Advantages
 Disadvantages
 Conclusion

3.  POWER LINE CARRIER COMMUNICATION is the technology which is used
to communicate between electric substations through existing electrical cables.
 POWER LINE CARRIER COMMUNICATION is mainly used for
telecommunication, tele-monitoring and tele-protection between electric
substations through power lines at high voltages. The data can be transfer at
9.6Kbits/sec over many miles of electrical cable.
 It’s equipment are used to send/receive speech/data/teleprotection signals.
 It is the most economical and reliable method of communication for medium or
long distance

4.  Since telephone communication system can not be directly connected to
the high voltage lines, suitably designed coupling devices have to be
employed.
 Coupling devices consists of high voltage capacitors in conjunction
with suitable line matching units(LMU’s) for line impedance matching to
that of the co-axial cable connecting the unit to the PLC transmit-receive
equipment.
 Carrier currents used for communication have to be prevented from
entering the power equipment used in GSS as this would results in complete
loss of power system.

5.  The signals that can be transmitted over the PLCC can
include:
1)Speech signal(300-2000Hz)
2)Data signal(2000-3000Hz)

8.  PLCC station
 Line matching circuit
 CVT/CC
 Earth switch
 Lightening Arrestor
 Wave Trap
 Co axial Cable

9.  It is the station where (modulation)Transmission,
Receiving(Demodulation), Amplification and Filtration are
performed.
 Frequency Range : 40 – 500 KHz
 Audio Bandwidth : 4 KHz
 Output Power : 10 – 80 W
ABB PLCC TERMINAL ETL-41

10. TRANSMITTER RECEIVER

11.  For impedance matching between line and coaxial cable,
includes high voltage protection devices like drainage
coil(20mH), lightening arrestor(500V) and an earth switch.


13.  It is connected between the line matching unit and the power
lines to block the high voltage entering to PLCC equipment.
 It couples high frequency carries with power line.

15.  Earth Switch: This is used for the maintenances of LMU.
The main function of Earth switch is to ground
the trapped charges.
 Lightning Arrestor: This is used for arresting any A.C. high
voltages spike entering to the
line matching unit.
 Co- Axial cable: This is used for interconnection between
PLCC Station and LMU for carrying high frequency signal.

16.  Wave traps – (WT’s) are used between the transmission line and the power
stations to avoid carrier power dislocation in the power plant and cross talk
with other power line carrier circuits connected to the same power station.
 WT’s also ensure proper operating conditions and signal levels at the
PLCC transmit receive equipment irrespective of switching conditions of
the power circuits and equipment in the station.
 A wave trap must satisfy the following requirements:
 1) It must block the carrier currents. By blocking, we mean that the
track should attenuate the H.F. signals by at least 8 to 10 dB.
 2) It must carry the power frequency current safely during normal
operation as well as during short circuit fault conditions.

18.  The power frequency and radio frequency are sorted by
this arrangement
 Carrier currents are prevented to enter station bus by
wave trap & power frequency current is blocked by
coupling capacitor, from the PLC equipment.
 Hence we get the power current at the bus & carrier
current at PLC equipment.

19.  Phase to ground coupling

20.  Phase to phase coupling

21.  Inter line or Inter circuit coupling

23.  PLCC work on rectified AC or main supply, when supply goes
off, it make use of a device for proper functioning of PLCC
called Battery Charger.
 This is the device that provide supply to the PLCC equipment
for uninterrupted working.
 It provide DC to the panel by battery.

24.  FAULT analysis
 In fault analysis the faulty devices are checked in this serial or
manner
1. Telephone or tale operation signal
2. Cabling low frequency circuit or DC power supply
3. PLC equipment.
4. HF transmission path.

25.  PLCC Unit Provide Five type of operation:
1:TELEPHONE FACILITES
2:COMPRESSOR & EXPANDER
3:EMERGENCY CALL
4:SIGNAL BOOSTING
5:SUPERVISION & ALARMS

26.  1. No separate wires are needed for communication purposes, as the power
lines themselves carry power as well as communication signals. Hence the
cost is less.
 2. Power lines have appreciably higher mechanical strength compared with
ordinary lines. They would normally remain unaffected under the
conditions, which might seriously damage telephone lines.
 3. Power lines usually provide the shortest route between the power
stations.
 4. Power lines have large cross-sectional area resulting in very low
resistance per unit length. Consequently carrier signals suffer much less
attenuation than when they travel on telephone lines of equal lengths.
 5. Power lines are well insulated to provide only negligible leakage
between conductors and ground even in adverse weather conditions
 6. Largest spacing between conductors reduces capacitance, which results
in smaller attenuation at high frequencies. The large spacing also reduces
the cross talk to a considerable extent.

27.  1. Proper care has to be taken to guard carrier equipment and
persons using them against high voltages and currents on the
lines.
 2. High voltage lines have transformer connections, attenuate
carrier currents. Sub-station equipments adversely affect the
carrier currents.
 3. Noise introduced by power lines is far more than in case of
telephone lines. This is due to the noise generated by discharge
across insulators, corona and switching processes.
 4. The noise is also introduced in the signal due to bad
weather conditions.

28. Power line carrier communication has been found to be the
most economical and reliable method for communication in a
medium and over long distance in a power system.

29. THANK YOU