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Powerlinecarrier (3)

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Power line carrier communication (PLCC) is a method of transmitting information over existing power lines. It works by injecting a high frequency signal over electrical power lines. PLCC has been found to be an economical and reliable method of medium to long distance communication. It uses the power lines as a communication medium by varying a carrier signal to convey information. A few common modulation techniques used in PLCC networks include OFDM, GMSK, and DSSS. Security is an important issue for PLCC since it operates over a shared channel like Wi-Fi and requires encryption. PLCC provides communication infrastructure without additional wiring and utilizes the existing power grid.

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Submitted by- : Ajay Singh
 Power line carrier communication is the method of transmitting information using power network.  Power Line Carrier communication systems consist of a high frequency signal injection over the electrical power line.  Power line carrier communication has been found to be the most economical and reliable method of communication for medium or long distance.  PLCC work on rectified AC or main supply, when supply goes off , make use of a device for proper functioning of PLCC called battery charger.
Process of varying a carrier signal to use the signal to convey information
 A power line carrier (PLC) communication system operating on a conventional three wire Hot (H), Neutral (N) and Ground (G) wires power line.  Pairs H, N and G wires of the power line are selected in sequence for transmission of the PLC system RF and the pair that results in the best communication between a system transmitter and receiver is used for continuing communication.  The telephone communication system cannot be directly connected to the high voltage lines suitably designed coupling devices.  These usually consist of high voltage capacitor with polaritical devices used in conjunction with suitable line matching unit (LMU).
 Not Designed for High Frequencies.  Power line "hostile" to signal propagation. Attenuation in PLC  Decrease in amplitude of an electrical signal  Opposite of amplification  Dependant upon Impedance. Impedance in PLC  Maximum signal received only when impedance of all components (transmitter, power line, receiver) match.  Power line systems vary significantly, also varies with signal frequencies, time, load pattern.
 Major source: Electrical Appliance  e.g. run vacuum cleaner when TV On.  50 Hz  Also in radio signals from broadcast, commercial, military, CB, amateur stations.  Categories of Appliance noise  Impulsive: on/off switches  Periodic impulsive: dimmers  Continuous impulsive: AC motors (vacuum, shavers).
The modulation used in plcc network are followings-:  Orthogonal frequency division multiplexing(OFDM).  Gaussian Minimum Shift Keying(GSMK).  Direct Sequence Spread Spectrum(DSSS).
 Ability to overcome nonlinear channel characteristics.  PLC is very nonlinear  Requires expensive, complex equalization to obtain more than 10 Mbps.  Should overcome without highly involved channel equalization  Ability to adjust dynamically  PLC changes with load  Must track without large overhead or complexity
X-10 Protocol  It is originally unidirectional controller to devices  Typically, signals over PL to receivers controlling lights & appliances.  Poor bandwidth utilization from 60 bps on 60 Hz line  Poor reliability in noisy environments.  Limited application. CE Bus Protocol  Peer-to-peer communication  It avoids collisions via CSMA/CRCD protocol (carrier sense multiple access/collision resolution & collision detection)  Physical layer: spread spectrum technology patented by Intellon Corp.  Data rate ~10kb/s  Frequency used limits use in North America.
Lon Works Protocol  It Uses CSMA  Narrow band spread spectrum modulation i.e 125 to 140 kHz.  Patented noise cancellation technique means Preserves data in presence of noise.  It can be used in N. America and Europe Due to narrow band. Home Plug 1.0 Protocol  It Still uses DSL or cable for Internet into home.  CSMA/CA for collision avoidance  MAC stands for medium access control and maintain virtual timer.  Physical layer detects preamble of frame.
 No separate wires are needed for communication purpose.  Power lines provides the shortest route between the power station.  Both communication and power transfer can be possible on same circuit.  Implementation cost is reduced.  Increased reliability.
 High voltage lines have transformer connections, which attenuate carrier currents.  Noise introduced by power lines is far more than in case of telephone lines.  Reflection are produced on spur lines connected to high voltage line. This increased attenuation and create other problem.
 Point to point communication.  Load shading.  Power line protection.  Fault indicator
 PLC is shared channel (like Wi-Fi)  Robust security is serious issue.  Encryption necessary in security as well as in complexity  Rivest: 128 bit key  Home Plug: DES - 56 bit key  Intrusion & interference from adjacent subnets  Decoupling filters - isolate circuits at meter.  Can also "separate" power line with router.
• The electric power grid is about to face an important renewal in which the information and communication technologies are of vital importance. but this technology Use of Power grid for communication. •it is important to have a solid communication and Extensive infrastructure in Every Building. •PLCC networks provide a proprietary solution and enough reliability and quality conditions
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Powerlinecarrier (3)

  • 1. Submitted by- : Ajay Singh
  • 2.  Power line carrier communication is the method of transmitting information using power network.  Power Line Carrier communication systems consist of a high frequency signal injection over the electrical power line.  Power line carrier communication has been found to be the most economical and reliable method of communication for medium or long distance.  PLCC work on rectified AC or main supply, when supply goes off , make use of a device for proper functioning of PLCC called battery charger.
  • 3. Process of varying a carrier signal to use the signal to convey information
  • 4.  A power line carrier (PLC) communication system operating on a conventional three wire Hot (H), Neutral (N) and Ground (G) wires power line.  Pairs H, N and G wires of the power line are selected in sequence for transmission of the PLC system RF and the pair that results in the best communication between a system transmitter and receiver is used for continuing communication.  The telephone communication system cannot be directly connected to the high voltage lines suitably designed coupling devices.  These usually consist of high voltage capacitor with polaritical devices used in conjunction with suitable line matching unit (LMU).
  • 5.  Not Designed for High Frequencies.  Power line "hostile" to signal propagation. Attenuation in PLC  Decrease in amplitude of an electrical signal  Opposite of amplification  Dependant upon Impedance. Impedance in PLC  Maximum signal received only when impedance of all components (transmitter, power line, receiver) match.  Power line systems vary significantly, also varies with signal frequencies, time, load pattern.
  • 6.  Major source: Electrical Appliance  e.g. run vacuum cleaner when TV On.  50 Hz  Also in radio signals from broadcast, commercial, military, CB, amateur stations.  Categories of Appliance noise  Impulsive: on/off switches  Periodic impulsive: dimmers  Continuous impulsive: AC motors (vacuum, shavers).
  • 7. The modulation used in plcc network are followings-:  Orthogonal frequency division multiplexing(OFDM).  Gaussian Minimum Shift Keying(GSMK).  Direct Sequence Spread Spectrum(DSSS).
  • 8.  Ability to overcome nonlinear channel characteristics.  PLC is very nonlinear  Requires expensive, complex equalization to obtain more than 10 Mbps.  Should overcome without highly involved channel equalization  Ability to adjust dynamically  PLC changes with load  Must track without large overhead or complexity
  • 9. X-10 Protocol  It is originally unidirectional controller to devices  Typically, signals over PL to receivers controlling lights & appliances.  Poor bandwidth utilization from 60 bps on 60 Hz line  Poor reliability in noisy environments.  Limited application. CE Bus Protocol  Peer-to-peer communication  It avoids collisions via CSMA/CRCD protocol (carrier sense multiple access/collision resolution & collision detection)  Physical layer: spread spectrum technology patented by Intellon Corp.  Data rate ~10kb/s  Frequency used limits use in North America.
  • 10. Lon Works Protocol  It Uses CSMA  Narrow band spread spectrum modulation i.e 125 to 140 kHz.  Patented noise cancellation technique means Preserves data in presence of noise.  It can be used in N. America and Europe Due to narrow band. Home Plug 1.0 Protocol  It Still uses DSL or cable for Internet into home.  CSMA/CA for collision avoidance  MAC stands for medium access control and maintain virtual timer.  Physical layer detects preamble of frame.
  • 11.  No separate wires are needed for communication purpose.  Power lines provides the shortest route between the power station.  Both communication and power transfer can be possible on same circuit.  Implementation cost is reduced.  Increased reliability.
  • 12.  High voltage lines have transformer connections, which attenuate carrier currents.  Noise introduced by power lines is far more than in case of telephone lines.  Reflection are produced on spur lines connected to high voltage line. This increased attenuation and create other problem.
  • 13.  Point to point communication.  Load shading.  Power line protection.  Fault indicator
  • 14.  PLC is shared channel (like Wi-Fi)  Robust security is serious issue.  Encryption necessary in security as well as in complexity  Rivest: 128 bit key  Home Plug: DES - 56 bit key  Intrusion & interference from adjacent subnets  Decoupling filters - isolate circuits at meter.  Can also "separate" power line with router.
  • 15. • The electric power grid is about to face an important renewal in which the information and communication technologies are of vital importance. but this technology Use of Power grid for communication. •it is important to have a solid communication and Extensive infrastructure in Every Building. •PLCC networks provide a proprietary solution and enough reliability and quality conditions