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Power Line Carrier Communication seminar

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Power Line Carrier Communication seminar

  1. 1. The Seminar Topic is based On Power Line Carrier Communication Presented ByAishwary verma .
  2. 2. 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
  3. 3. 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.
  4. 4. 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)
  5. 5. 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 
  6. 6. SPECIFICATIONS OF PLCC 1)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
  7. 7. BASIC PRINCIPLE OF PLCC In PLCC the higher mechanical strength and insulation level of high voltage power lines result in increased reliability of communication and lower attenuation over long-distance. 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 result in high attenuation of even complete loss of communication signals when earthed at isolator.
  8. 8.  To prevent loss of communication signals, wave traps or line traps are employed. These consist of suitably designed choke coils connected in series with the line, which offer higher impedance to RF carrier currents.  Wave traps also usually have one or more suitably designed capacitors connected in parallel with the choke coils so as to resonate at carrier frequencies and thus offer even negligible impedance to the flow of RF currents.  The RF is prevented from entering the stations bus(yard) and the power frequency is blocked of coupling capacitor.
  9. 9. The basic arrangement of connecting the WT and coupling capacitor in PLCC communication is shown in the figure below –
  10. 10. (a) PHASE TO GROUND COUPLING
  11. 11. (b) PHASE TO PHASE COUPLING
  12. 12. (c) PHASE TO PHASE COUPLING
  13. 13. (d) INTERLINE OR INTER CIRCUIT COUPLING
  14. 14. WAVE TRAPS •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.
  15. 15. 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
  16. 16. BATTERY CHARGER   PLCC (Power Line Carrier Communication) works on rectified AC or main power supply. When supply goes off, we use BATTERY CHARGER for proper functioning of PLCC, which provides supply 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 series and individually per battery has approximately 2V capacity.   Battery charger mainly consists of 4 sections –   1.    Float charger 2.    Boost charger section 3.    Control section 4.    Alarm section
  17. 17. TECHNICAL SPECIFICATIONS   NORMAL INPUT INPUT VARIATION :415 V AC 3-PHASE : +/- 20% FLOAT CHARGER : DC OUTPUT OUTPUT CURRENT EFFICIENCY :50 V :20 TO 40 AMP : >70%
  18. 18.     BOOST CHARGER DC output Output current Efficiency - 43.2 to 67.2 V - 25-70 Amps. - >80%
  19. 19. APPLICATIONS  PLCC Unit Provide Five type of operation: 1:TELEPHONE FACILITES 2:COMPRESSOR & EXPANDER 3:EMERGENCY CALL 4:SIGNAL BOOSTING 5:SUPERVISION & ALARMS
  20. 20. ADVANTAGES 2 2 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.
  21. 21. DISADVANTAGES 1. Proper care has to be taken to guard carrier equipment and persons using them against high voltages and currents on the lines. 2. Reflections are produced on lines connected to high voltage lines. This increases attenuation and creates problem. 3. High voltage lines have transformer connections, attenuate carrier currents. Sub-station equipments adversely affect the carrier currents. 4.  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. It is obvious that an effective power lines carrier system must overcome these difficulties.
  22. 22. CONCLUSION 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.
  23. 23. THANK YOU
  24. 24. QUERIES ?

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