Technical Paper Title: POWER LINE COMMUNICATION
Authors:P.Kalyani, M.Manjusha & J.rama Dhutheswari, 2nd year BTech,EEE
College: Sai Spurthi Institute Of Technology, Sattupally, Khammam
Power line communication or power line carrier (PLC), also known as Power line Digital Subscriber Line (PDSL), mains communication, power line telecom (PLT), or power line networking (PLN), or Broadband over Power Lines (BPL) are systems for carrying data on a conductor also used for electric power transmission.
Electrical power is transmitted over high voltage transmission lines, distributed over medium voltage, and used inside buildings at lower voltages. Powerline communications can be applied at each stage. Most PLC technologies limit themselves to one set of wires (for example, premises wiring), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically the transformer prevents propagating the signal so multiple PLC technologies are bridged to form very large networks.
INTRODUCTION
All power line communications systems operate by impressing a modulated carrier signal on the wiring system. Different types of powerline communications use different frequency bands, depending on the signal transmission characteristics of the power wiring used. Since the power wiring system was originally intended for transmission of AC power, in conventional use, the power wire circuits have only a limited ability to carry higher frequencies. The propagation problem is a limiting factor for each type of power line communications. A new discovery called E-Line that allows a single power conductor on an overhead power line to operate as a waveguide to provide low attenuation propagation of RF through microwave energy lines while providing information rate of multiple Gbps is an exception to this limitation.
Data rates over a power line communication system vary widely. Low-frequency (about 100-200 kHz) carriers impressed on high-voltage transmission lines may carry one or two analog voice circuits, or telemetry and control circuits with an equivalent data rate of a few hundred bits per second; however, these circuits may be many miles long. Higher data rates generally imply shorter ranges; a local area network operating at millions of bits per second may only cover one floor of an office building, but eliminates installation of dedicated network cabling.
BLOCK DIAGRAM
CONTENTS
• Ultra-High-frequency communication (≥100 MHz)
• High-frequency communication (≥MHz)
• Medium frequency (kHz)
• Broadband over power line (BPL)
• Apparatus
• Applications
• Conclusion
Ultra-High-frequency communication (≥100 MHz)
The highest information rate transmissions over power line use RF through microwave frequencies transmitted via trasverse mode surface wave propagation mechanism that requires only a single ). An implementation of this technology called E-line has been demonstrated using a single power line conductor. These systems have demonstrated symmetric and full duplex communicationeach direction. Multiple WiFi channels with simultaneous analog television in the 2.4 and 5.3 GHz unlicensed bands have been demonstrated operating over a single medium voltage line conductor. Because the underlying propagation mode is extremely broadband, it can operate anywhere in the 20 MHz – 20 GHz region. Also since it is not restricted to <80 MHz, as is the case for high-frequency BPL, these systems can avoid the need to share spectrum with other licensed or unlicensed services and can completely avoid the interference issues associated with use of shared spectrum
High-frequency communication (≥MHz)
High frequency communication may (re)use large portions of the radio spectrum for communication, or may use select (narrow) band(s), depending on the technology.
Power line communications can also be used to interconnect home computers, peripherals or other networked consumer peripherals. Specifications for power line home networking have been developed by a number of different companies within the framework of the HomePlug Powerline Alliance, the Universal Powerline Association and the HD-PLC Alliance.
Medium frequency (kHz)
Home control (narrowband)
Power line communications technology can use the household electrical power wiring as a transmission medium. INSTEON and X10 are the two most popular[de facto standards using power line communications for home control. This is a technique used in home automation for remote control of lighting and appliances without installation of additional control wiring.
Typically home-control power line communication devices operate by modulating in a carrier wave of between 20 and 200 kHz into the household wiring at the transmitter. The carrier is modulated by digital signals. Each receiver in the system has an address and can be individually commanded by the signals transmitted over the household wiring and decoded at the receiver. These devices may be either plugged into regular power outlets, or permanently wired in place. Since the carrier signal may propagate to nearby homes (or apartments) on the same distribution system, these control schemes have a “house address” that designates the owner.
Since 1999, a new power-line communication technology “universal powerline bus” has been developed, using pulse-position modulation (PPM). The physical layer method is a very different scheme than the modulated/demodulated RF techniques used by X-10. The promoters claim advantages in cost per node, and reliability.
Medium frequency (kHz)
Home control (narrowband)
Power line communications technology can use the household electrical power wiring as a transmission medium. INSTEON and X10 are the two most popular[de facto standards using power line communications for home control. This is a technique used in home automation for remote control of lighting and appliances without installation of additional control wiring.
Typically home-control power line communication devices operate by modulating in a carrier wave of between 20 and 200 kHz into the household wiring at the transmitter. The carrier is modulated by digital signals. Each receiver in the system has an address and can be individually commanded by the signals transmitted over the household wiring and decoded at the receiver. These devices may be either plugged into regular power outlets, or permanently wired in place. Since the carrier signal may propagate to nearby homes (or apartments) on the same distribution system, these control schemes have a “house address” that designates the owner.
Since 1999, a new power-line communication technology “universal powerline bus” has been developed, using pulse-position modulation (PPM). The physical layer method is a very different scheme than the modulated/demodulated RF techniques used by X-10. The promoters claim advantages in cost per node, and reliability.
Broadband over power line (BPL)
On 14 October 2004, the U.S. Federal Communications Commission adopted rules to facilitate the deployment of “Access BPL” — i.e., use of BPL to deliver broadband service to homes and businesses. The technical rules are more liberal than those advanced by the US national amateur radio organization, the ARRL, and other spectrum users, but include provisions that require BPL providers to investigate and correct any interference they cause. These rules may be subject to future litigation.
On 8 August 2006 FCC adopted a memorandum opinion and an order on broadband over power lines, giving the go-ahead to promote broadband service to all Americans. The order rejects calls from aviation, business, commercial, amateur radio and other sectors of spectrum users to limit or prohibit deployment until further study is completed. FCC chief Kevin Martin said that BPL “holds great promise as a ubiquitous broadband solution that would offer a viable alternative to cable, digital subscriber line, fiber, and wireless broadband solutions”, and that BPL was one of the agency’s “top priorities”.
APPARATUS
Electrical installations, Low-voltage installations, Electrical equipment, Signals, Mains electricity supply, Industrial electrical installations, Frequencies, Electromagnetic compatibility, Electric power transmission lines, Electric cables, Communication cables, Domestic electrical installations, Industrial facilities, Domestic facilities, Business facilities
APPLICATIONS
Automotive uses
Power-line technology enables in-vehicle network communication of data, voice, music and video signals by digital means over direct current (DC) battery power-line. Advanced digital communication techniques tailored to overcome hostile and noisy environment are implemented in a small size silicon device. One power line can be used for multiple independent networks. The benefits would be lower cost and weight (compared to separate power and control wiring), flexible modification, and ease of installation. Potential problems in vehicle applications would include the higher cost of end devices, which must be equipped with active controls and communication, and the possibility of intereference with other radio frequency devices in the vehicle or other places.
Prototypes are successfully operational in vehicles, using automotive compatible protocols such as CAN-bus, LIN-bus over power line (DC-LIN) and [DC-bus]
LonWorks power line based control has been used for an HVAC system in a production model bus
CONCLUSION
Power Line Communications (PLC) is a promising emerging technology, which has attracted much attention due to the wide availability of power distribution lines. This book provides a thorough introduction to the use of power lines for communication purposes, ranging from channel characterization, communications on the physical layer and electromagnetic interference, through to protocols, networks, standards and up to systems and implementations. With contributions from many of the most prominent international PLC experts from academia and industry, “Power Line Communications” brings together a wealth of information on PLC specific topics that provide the reader with a broad coverage of the major developments within the field. Acts as a single source reference guide to PLC collating information that is widely dispersed in current literature, such as in research papers and standards. Covers both the state of the art, and ongoing research topics. Considers future developments and deployments of PLC
REFERENCES
• Blackburn, J. L., ed (1976). Applied Protective Relaying. Newark, N.J.: Westinghouse Electric Corp., Relay-Instrument Division.
• Carcelle, Xavier (2006) (in French). Réseaux CPL par la pratique. Paris: