The Seminar Topic is basedThe Seminar Topic is basedOnOn

Power Line Carrier CommunicationPower Line Carrier Communication

Presented By-Presented By-Aishwary verma . Aishwary verma .

CONTENTS INTRODUCTION OF PLCC GENERAL DISCRIPTION OF PLCC BASIC PRINCIPLE OF PLCC CONSTRUCTION OF PLCC TYPES OF COUPLING WAVETRAPS BATTERY CHARGER ADVANTAGES AND DISADVANTAGES OF

PLCC CONCLUSION

INTRODUCTION OF PLCC POWER LINE CARRIER COMMUNICATION

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.

For sending speech or other signals from point to point in an interconnected power grid many communication methods can be used. Some of them are as following: . Public Telephone Network    . Direct Lines . Radio Circuits . Power Line Carrier Communication(PLCC)

GENERAL MODULATION PRINCIPLE

SINGLE SIDE BAND TRANSMISSION CARRIER FREQUENCY IS SPACED ON A

4-KHZ I.F. FIXED AT 16-KHZ FULL DUPLEX MODE IS USED LOWER SIDE BAND IS USED

THROUGHOUT ALL COMMUNICATION

SPECIFICATIONS OF PLCC1)GENERAL - Carrier frequency range :- 40 to 512 KHz Useful AF band :- 300 to 3,700 Hz

2)TRNSMITTER R.F.TRANSMITTING POWER;

-peak envelope power:- 25 W

-side band power :- 15 W

BASIC PRINCIPLE OF PLCCBASIC PRINCIPLE OF PLCCIn PLCC the higher mechanical strength and In PLCC the higher mechanical strength and

insulation level of high voltage power lines result in insulation level of high voltage power lines result in increased reliability of communication and lower increased reliability of communication and lower attenuation over long-distance. attenuation over long-distance.

Since telephone communication system can not Since telephone communication system can not be directly connected to the high voltage lines, be directly connected to the high voltage lines, suitably designed coupling devices have to be suitably designed coupling devices have to be employed. employed.

Coupling devices consists of high voltage Coupling devices consists of high voltage capacitors in conjunction with suitable line matching capacitors in conjunction with suitable line matching units(LMU’s) for line impedance matching to that of units(LMU’s) for line impedance matching to that of the co-axial cable connecting the unit to the PLC the co-axial cable connecting the unit to the PLC transmit-receive equipment.transmit-receive equipment.

Carrier currents used for communication have to Carrier currents used for communication have to be prevented from entering the power equipment be prevented from entering the power equipment used in GSS as this would result in high attenuation used in GSS as this would result in high attenuation of even complete loss of communication signals of even complete loss of communication signals when earthed at isolator.when earthed at isolator.

To prevent loss of communication signals, wave To prevent loss of communication signals, wave traps or line traps are employed. These consist of traps or line traps are employed. These consist of suitably designed choke coils connected in series suitably designed choke coils connected in series with the line, which offer higher impedance to RF with the line, which offer higher impedance to RF carrier currents. carrier currents.

Wave traps also usually have one or more suitably Wave traps also usually have one or more suitably designed capacitors connected in parallel with the designed capacitors connected in parallel with the choke coils so as to resonate at carrier frequencies choke coils so as to resonate at carrier frequencies and thus offer even negligible impedance to the flow and thus offer even negligible impedance to the flow of RF currents. of RF currents.

The RF is prevented from entering the stations The RF is prevented from entering the stations bus(yard) and the power frequency is blocked of bus(yard) and the power frequency is blocked of coupling capacitorcoupling capacitor..

The basic arrangement of connecting the WT The basic arrangement of connecting the WT and couplingand coupling

capacitor in PLCC communication is shown in capacitor in PLCC communication is shown in the figure the figure

below – below –

(a) ) PHASE TO GROUND COUPLINGPHASE TO GROUND COUPLING

(b) (b) PHASE TO PHASE COUPLINGPHASE TO PHASE COUPLING

(c) (c) PHASE TO PHASE COUPLINGPHASE TO PHASE COUPLING

(d) (d) INTERLINE OR INTER CIRCUIT COUPLINGINTERLINE OR INTER CIRCUIT COUPLING

       WAVE TRAPSWAVE TRAPS•Wave traps Wave traps –– (WT (WT’’s) are used between the transmission line and the s) are used between the transmission line and the power stations to avoid carrier power dislocation in the power plant power stations to avoid carrier power dislocation in the power plant and cross talk with other power line carrier circuits connected to the and cross talk with other power line carrier circuits connected to the same power station. same power station.

TUNING CAPACITOR Used are high voltage, high stability

mica capacitors with low losses For lower voltage class of tuning units

with impulse test voltage rating upto 40 KV polystyrene capacitors are used

For higher voltage class of tuning units with impulse test voltage rating upto 150 KV, capacitors with mineral oil impregnated paper dielectric are used

  BATTERY CHARGERBATTERY CHARGER  

PLCC (Power Line Carrier Communication) works on rectified AC PLCC (Power Line Carrier Communication) works on rectified AC or main power supply. When supply goes off, we use BATTERY or main power supply. When supply goes off, we use BATTERY CHARGER for proper functioning of PLCC, which provides supply CHARGER for proper functioning of PLCC, which provides supply to the PLCC equipment for uninterrupted working. It provides DC to to the PLCC equipment for uninterrupted working. It provides DC to the panel by battery of 48V. In this type 24 batteries are connected in the panel by battery of 48V. In this type 24 batteries are connected in series and individually per battery has approximately 2V capacity.series and individually per battery has approximately 2V capacity.

   Battery charger mainly consists of 4 sections Battery charger mainly consists of 4 sections ––

  

1.1.       Float charger Float charger

2.2.       Boost charger section Boost charger section

3.3.       Control section Control section

4.4.       Alarm section Alarm section  

TECHNICAL SPECIFICATIONS

NORMAL INPUT :415 V AC 3-PHASE INPUT VARIATION : +/- 20%

FLOAT CHARGER : DC OUTPUT :50 V OUTPUT CURRENT :20 TO 40 AMP EFFICIENCY : >70%

BOOST CHARGER DC output - 43.2 to 67.2 V Output current - 25-70 Amps. Efficiency - >80%

APPLICATIONS

PLCC Unit Provide Five type of operation:

1:TELEPHONE FACILITES

2:COMPRESSOR & EXPANDER

3:EMERGENCY CALL

4:SIGNAL BOOSTING

5:SUPERVISION & ALARMS

ADVANTAGESADVANTAGES22

1. 1. No separate wires are needed for communication purposes, as the power No separate wires are needed for communication purposes, as the power lines themselves carry power as well as communication signals. Hence the lines themselves carry power as well as communication signals. Hence the cost is less.cost is less.

22 Power lines have appreciably higher mechanical strength compared with Power lines have appreciably higher mechanical strength compared with ordinary lines. They would normally remain unaffected under the conditions, ordinary lines. They would normally remain unaffected under the conditions, which might seriously damage telephone lines.which might seriously damage telephone lines.

3.3. Power lines usually provide the shortest route between the power stations.Power lines usually provide the shortest route between the power stations.

4.4. Power lines have large cross-sectional area resulting in very low resistance Power lines have large cross-sectional area resulting in very low resistance per unit length. Consequently carrier signals suffer much less attenuation per unit length. Consequently carrier signals suffer much less attenuation than when they travel on telephone lines of equal lengths.than when they travel on telephone lines of equal lengths.

5.5. Power lines are well insulated to provide only negligible leakage between Power lines are well insulated to provide only negligible leakage between conductors and ground even in adverse weather conditions. conductors and ground even in adverse weather conditions.

6. Largest spacing between conductors reduces capacitance, which results in 6. Largest spacing between conductors reduces capacitance, which results in smaller attenuation at high frequencies.smaller attenuation at high frequencies. The large spacing also The large spacing also reduces the cross talk to a considerable extent. reduces the cross talk to a considerable extent.

DISADVANTAGES

1. 1. Proper care has to be taken to guard carrier equipment and Proper care has to be taken to guard carrier equipment and persons using them against high voltages and currents on the lines.persons using them against high voltages and currents on the lines.

2.2.  Reflections are produced on lines connected to high voltage lines. Reflections are produced on lines connected to high voltage lines. This increases attenuation and creates problem.This increases attenuation and creates problem.

3.3.  High voltage lines have transformer connections, attenuate High voltage lines have transformer connections, attenuate carrier currents. Sub-station equipments adversely affect the carrier currents. Sub-station equipments adversely affect the carrier currents.carrier currents.

4.4.   Noise introduced by power lines is far more than in case of Noise introduced by power lines is far more than in case of telephone lines. This is due to the noise generated by discharge telephone lines. This is due to the noise generated by discharge across insulators, corona and switching processes.across insulators, corona and switching processes.

It is obvious that an effective power lines carrier system must It is obvious that an effective power lines carrier system must overcome these difficulties.overcome these difficulties.

CONCLUSIONCONCLUSION

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.

THANK YOU

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