Power-line communication (also known as power-line carrier or PLC) carries data on a conductor that is also used simultaneously for AC
electric power transmission
Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a ''transmission network''. This is ...
or
electric power distribution to consumers.
A wide range of power-line communication technologies are needed for different applications, ranging from
home automation
Home automation or domotics is building automation for a home, called a smart home or smart house. A home automation system will monitor and/or control home attributes such as lighting, climate, entertainment systems, and appliances. It m ...
to
Internet access
Internet access is the ability of individuals and organizations to connect to the Internet using computer terminals, computers, and other devices; and to access services such as email and the World Wide Web. Internet access is sold by Internet ...
which is often called
broadband over power lines
Broadband over power lines (BPL) is a method of power-line communication (PLC) that allows relatively high-speed digital data transmission over the public electric power distribution wiring. BPL uses higher frequencies, a wider frequency range and ...
(BPL). Most PLC technologies limit themselves to one type of wires (such as premises wiring within a single building), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically transformers prevent propagating the signal, which requires multiple technologies to form very large networks. Various data rates and frequencies are used in different situations.
A number of difficult technical problems are common between
wireless
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
and power-line communication, notably those of
spread spectrum radio signals operating in a crowded environment. Radio interference, for example, has long been a concern of
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...
groups.
Basics
Power-line
communications systems operate by adding a modulated carrier signal to the wiring system. Different types of power-line communications use different frequency bands. Since the power distribution system was originally intended for transmission of
AC power at typical frequencies of 50 or 60
Hz, 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.
The main issue determining the frequencies of power-line communication is laws to limit interference with radio services. Many nations regulate unshielded wired emissions as if they were radio transmitters. These jurisdictions usually require unlicensed uses to be below 500 kHz or in unlicensed radio bands. Some jurisdictions (such as the EU), regulate wire-line transmissions further. The U.S. is a notable exception, permitting limited-power wide-band signals to be injected into unshielded wiring, as long as the wiring is not designed to propagate radio waves in free space.
Data rates
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted. ...
and distance limits vary widely over many power-line communication standards. 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
A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a larger ...
operating at millions of bits per second may only cover one floor of an office building, but eliminates the need for installation of dedicated network cabling.
Ripple control
Ripple control adds an audio-frequency tone to an AC line. Typical frequencies are from 100
Hz to 2400Hz. Each district usually has its own frequency, so that adjacent areas are unaffected. Codes are sent by slowly turning the tone on and off. Equipment at a customer site receives the codes, and turns customer equipment off and on. Often the decoder is part of a standard
electricity meter
North American domestic analog electricity meter.
Electricity meter with transparent plastic case (Israel)
North American domestic electronic electricity meter
An electricity meter, electric meter, electrical meter, energy meter, or kilowa ...
, and controls relays. There are also utility codes, e.g. to set the clocks of the power meters at midnight.
In this way, the utility can avoid up to 20% of capital expenses for generating equipment. This lowers costs for electricity and fuel usage. Brownouts and rolling blackouts are more easily prevented. Grids that use
cogeneration
Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to generate electricity and useful heat at the same time.
Cogeneration is a more efficient use of fuel or heat, because otherwise- wasted heat from elect ...
can enable auxiliary customer equipment when the generators are being run to generate heat rather than electricity.
An annoyance for customers is that sometimes the code to turn equipment on is lost, or load shedding is inconvenient or dangerous. For example, during a party, a dangerous heat wave or when life-preserving medical equipment is on-site. To handle these cases, some equipment includes switches to circumvent load shedding. Some meters switch into a higher billing rate when the "party switch" is flipped.
Long haul, low frequency
Utility companies use special coupling
capacitor
A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals.
The effect of ...
s to connect radio transmitters and receivers to the AC power carrying conductors. Power meters often use small transformers with linear amplifiers in the range of tens of watts. Most of the expense of any PLC system is the power electronics. By comparison, the electronics to encode and decode is usually small, in a special purpose integrated circuit. Thus even the complicated OFDM standards can still be economical.
Frequencies used are in the range of 24 to 500 kHz, with transmitter power levels up to hundreds of
watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...
s. These signals may be impressed on one conductor, on two conductors or on all three conductors of a high-voltage AC transmission line. Several PLC channels may be coupled onto one HV line. Filtering devices are applied at substations to prevent the carrier frequency current from being bypassed through the station apparatus and to ensure that distant faults do not affect the isolated segments of the PLC system. These circuits are used for control of switchgear, and for protection of transmission lines. For example, a
protective relay can use a PLC channel to trip a line if a fault is detected between its two terminals, but to leave the line in operation if the fault is elsewhere on the system.
While utility companies use microwave and now, increasingly,
fiber optic cable
A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to an electrical cable, but containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with ...
s for their primary system communication needs, the power-line carrier apparatus may still be useful as a backup channel or for very simple low-cost installations that do not warrant installing fiber optic lines, or which are inaccessible to radio or other communication.
Power-line carrier communication (PLCC) is mainly used for
telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
, tele-protection and tele-monitoring between
electrical substation
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Between the generating station and ...
s through
power lines at
high voltage
High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant spec ...
s, such as 110 kV, 220 kV, 400 kV.
The modulation generally used in these system is
amplitude modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to ...
. The carrier frequency range is used for audio signals, protection and a pilot frequency. The pilot frequency is a signal in the audio range that is transmitted continuously for failure detection.
The voice signal is compressed and filtered into the 300 Hz to 4000 Hz range, and this audio frequency is mixed with the carrier frequency. The carrier frequency is again filtered, amplified and transmitted. The transmission power of these HF carrier frequencies will be in the range of 0 to +32
dbW
The decibel watt (dBW or dBW) is a unit for the measurement of the strength of a signal expressed in decibels relative to one watt. It is used because of its capability to express both very large and very small values of power in a short range of ...
. This range is set according to the distance between substations.
PLCC can be used for interconnecting
private branch exchange
A business telephone system is a multiline telephone system typically used in business environments, encompassing systems ranging in technology from the key telephone system (KTS) to the private branch exchange (PBX).
A business telephone syst ...
s (PBXs).
To sectionalize the transmission network and protect against failures, a "wave trap" is connected in series with the power (transmission) line. They consist of one or more sections of resonant circuits, which block the high frequency carrier waves (24 kHz to 500 kHz) and let power frequency current (50 Hz – 60 Hz) pass through. Wave traps are used in switchyard of most power stations to prevent carrier from entering the station equipment. Each wave trap has a lightning arrester to protect it from surge voltages.
A coupling capacitor is used to connect the transmitters and receivers to the high voltage line. This provides low impedance path for carrier energy to HV line but blocks the power frequency circuit by being a high impedance path. The coupling capacitor may be part of a
capacitor voltage transformer
Voltage transformers (VT), also called potential transformers (PT), are a parallel-connected type of instrument transformer. They are designed to present a negligible load to the supply being measured and have an accurate voltage ratio and phase r ...
used for voltage measurement.
Power-line carrier systems have long been a favorite at many utilities because it allows them to reliably move data over an infrastructure that they control.
A ''PLC carrier repeating station'' is a facility, at which a power-line communication (PLC) signal on a
powerline is refreshed. Therefore
the signal is filtered out from the powerline,
demodulated and
modulated
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
on a new
carrier frequency, and then reinjected onto the powerline again. As PLC signals can carry long distances (several hundred kilometres), such facilities only exist on very long power lines using PLC equipment.
PLC is one of the technologies used for automatic meter reading. Both one-way and two-way systems have been successfully used for decades. Interest in this application has grown substantially in recent history—not so much because there is an interest in automating a manual process, but because there is an interest in obtaining fresh data from all metered points in order to better control and operate the system. PLC is one of the technologies being used in
Advanced Metering Infrastructure
A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor. Smart meters communicate the information to the consumer for greater clarity of consumption beha ...
(AMI) systems.
In a one-way (inbound only) system, readings "bubble up" from end devices (such as meters), through the communication infrastructure, to a "master station" which publishes the readings. A one-way system might be lower-cost than a two-way system, but also is difficult to reconfigure should the operating environment change.
In a two-way system (supporting both outbound and inbound), commands can be broadcast out from the master station to end devices (meters) – allowing for reconfiguration of the network, or to obtain readings, or to convey messages, etc. The device at the end of the network may then respond (inbound) with a message that carries the desired value. Outbound messages injected at a utility substation will propagate to all points downstream. This type of broadcast allows the communication system to simultaneously reach many thousands of devices—all of which are known to have power, and have been previously identified as candidates for load shed. PLC also may be a component of a
smart grid
A smart grid is an electrical grid which includes a variety of operation and energy measures including:
*Advanced metering infrastructure (of which smart meters are a generic name for any utility side device even if it is more capable e.g. a f ...
.
Medium frequency (100 kHz)
These systems are often used in countries in which it is illegal to transmit signals that interfere with normal radio. The frequencies are so low that they are unable to start radio waves when sent over the utility wiring.
Home control (narrowband)
Power-line communications technology can use the electrical power wiring within a home for
home automation
Home automation or domotics is building automation for a home, called a smart home or smart house. A home automation system will monitor and/or control home attributes such as lighting, climate, entertainment systems, and appliances. It m ...
: for example, 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
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that on ...
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. A popular technology known as
X10 has been used since the 1970s.
The "
universal powerline bus Universal Powerline Bus (UPB) is a proprietary software protocol developed bPowerline Control Systemsfor power-line communication between devices used for home automation. Household electrical wiring is used to send digital data between UPB devices ...
", introduced in 1999, uses
pulse-position modulation (PPM). The physical layer method is a very different scheme than the X10.
LonTalk
LonTalk is a protocol optimized for control. Originally developed by Echelon Corporation for networking devices over media such as twisted pair, powerlines, fiber optics, and RF. It is popular for the automation of various functions in industri ...
, part of the
LonWorks home automation product line, was accepted as part of some automation standards.
Low-speed narrow-band
Narrowband power-line communications began soon after electrical power supply became widespread. Around the year 1922 the first carrier frequency systems began to operate over high-tension lines with frequencies of 15 to 500 kHz for telemetry purposes, and this continues. Consumer products such as baby alarms have been available at least since 1940.
In the 1930s, ripple carrier signaling was introduced on the medium (10–20 kV) and low voltage (240/415 V) distribution systems.
For many years the search continued for a cheap bi-directional technology suitable for applications such as remote meter reading. French electric power ''
Électricité de France
Électricité de France S.A. (literally ''Electricity of France''), commonly known as EDF, is a French multinational electric utility company, largely owned by the French state. Headquartered in Paris, with €71.2 billion in revenues in 2 ...
'' (EDF) prototyped and standardized a system called "spread frequency shift keying" or S-FSK. (See
IEC 61334 IEC 61334, known as Distribution automation using distribution line carrier systems, is a standard for low-speed reliable power line communications by electricity meters, water meters and SCADA.
It is also known as spread frequency-shift keying ( ...
) It is now a simple, low cost system with a long history, however it has a very slow transmission rate. In the 1970s, the Tokyo Electric Power Co ran experiments which reported successful bi-directional operation with several hundred units. The system is now (2012) widely used in Italy and some other parts of the EU.
S-FSK sends a burst of 2, 4 or 8 tones centered around the time when the AC line passes through zero voltage. In this way, the tones avoid most radio-frequency noise from arcing. (It is common for dirty insulators to arc at the highest point of the voltage, and thus generate a wide-band burst of noise.) To avoid other interference, receivers can improve their signal-to-noise ratio by measuring the power of only the "1" tones, only the "0" tones or the differential power of both. Different districts use different tone pairs to avoid interference. The bit timing is typically recovered from the boundaries between tones, in a way similar to a
UART. Timing is roughly centered on the zero crossing with a timer from the previous zero crossing. Typical speeds are 200 to 1200 bits per second, with one bit per tone slot. Speeds also depend on the AC line frequency. The speed is limited by noise, and the jitter of the AC line's zero crossing, which is affected by local loads. These systems are usually bidirectional, with both meters and central stations sending data and commands. Higher levels of the protocols can have stations (usually smart meters) retransmit messages. (See
IEC 61334 IEC 61334, known as Distribution automation using distribution line carrier systems, is a standard for low-speed reliable power line communications by electricity meters, water meters and SCADA.
It is also known as spread frequency-shift keying ( ...
)
Since the mid-1980s, there has been a surge of interest in using the potential of digital communications techniques and
digital signal processing
Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are ...
. The drive is to produce a reliable system which is cheap enough to be widely installed and able to compete cost effectively with wireless solutions. But the narrowband powerline communications channel presents many technical challenges, a mathematical channel model and a survey of work is available.
Applications of mains communications vary enormously, as would be expected of such a widely available medium. One natural application of narrow band power-line communication is the control and
telemetry
Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Gr ...
of electrical equipment such as meters, switches, heaters and domestic appliances. A number of active developments are considering such applications from a systems point of view, such as
demand side management. In this, domestic appliances would intelligently co-ordinate their use of resources, for example limiting peak loads.
Control and telemetry applications include both 'utility side' applications, which involves equipment belonging to the utility company up to the domestic meter, and 'consumer-side' applications which involves equipment in the consumer's premises. Possible utility-side applications include
automatic meter reading (AMR), dynamic tariff control, load management, load profile recording, credit control, pre-payment, remote connection, fraud detection and network management, and could be extended to include gas and water.
Open Smart Grid Protocol (OSGP) is one of the most proven narrowband PLC technologies and protocols for smart metering. There are more than five million smart meters, based on OSGP and using BPSK PLC, installed and operating around the World. The OSGP Alliance, a non-profit association originally established as ESNA in 2006, led an effort to establish a family of specifications published by the European Telecommunications Standards Institute (ETSI) used in conjunction with the ISO/IEC 14908 control networking standard for smart grid applications. OSGP is optimized to provide reliable and efficient delivery of command and control information for smart meters, direct load control modules, solar panels, gateways, and other smart grid devices. OSGP follows a modern, structured approach based on the OSI protocol model to meet the evolving challenges of the smart grid.
At the physical layer, OSGP currently uses ETSI 103 908 as its technology standard. This uses binary phase shift keying at 3592.98 BAUD, using a carrier tone of 86.232KHz +/- 200ppm. (Note: The bit clock is almost exactly 1/24 of the carrier.) At the OSGP application layer, ETSI TS 104 001 provides a table-oriented data storage based, in part, on the ANSI C12.19 / MC12.19 / 2012 / IEEE Std 1377 standards for Utility Industry End Device Data Tables and ANSI C12.18 / MC12.18 / IEEE Std 1701, for its services and payload encapsulation. This standard and command system provides not only for smart meters and related data but also for general purpose extension to other smart grid devices.
A project of EDF, France includes demand management, street lighting control, remote metering and billing, customer specific tariff optimisation, contract management, expense estimation and gas applications safety.
There are also many specialised niche applications which use the mains supply within the home as a convenient data link for telemetry. For example, in the UK and Europe a TV audience monitoring system uses powerline communications as a convenient data path between devices that monitor TV viewing activity in different rooms in a home and a data
concentrator which is connected to a telephone modem.
Medium-speed narrow-band
The Distribution Line Carrier (DLC) System technology used a frequency range of 9 to 500 kHz with data rate up to 576 kbit/s.
A project called Real-time Energy Management via Powerlines and Internet (REMPLI) was funded from 2003 to 2006 by the
European Commission
The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
.
More modern systems use
OFDM to send data at faster bit rates without causing radio frequency interference. These utilize hundreds of slowly-sending data channels. Usually they can adapt to noise by turning off channels with interference. The extra expense of the encoding devices is minor compared to the cost of the electronics to transmit. The transmission electronics is usually a high power operational amplifier, a coupling transformer and a power supply. Similar transmission electronics is required on older, slower systems, so with improved technology, improved performance can be very affordable.
In 2009, a group of vendors formed the PoweRline Intelligent Metering Evolution (PRIME) alliance. As delivered, the physical layer is
OFDM, sampled at 250 kHz, with 512
differential phase shift keying
Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at ...
channels from 42–89 kHz. Its fastest transmission rate is 128.6 kilobits/second, while its most robust is 21.4 kbit/s. It uses a
convolutional code
In telecommunication, a convolutional code is a type of error-correcting code that generates parity symbols via the sliding application of a boolean polynomial function to a data stream. The sliding application represents the 'convolution' of the ...
for error detection and correction. The upper layer is usually
IPv4
Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...
.
In 2011, several companies including distribution network operators (
ERDF, Enexis), meter vendors (
Sagemcom, Landis&Gyr) and chip vendors (
Maxim Integrated,
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
,
STMicroelectronics
STMicroelectronics N.V. commonly referred as ST or STMicro is a Dutch multinational corporation and technology company of French-Italian origin headquartered in Plan-les-Ouates near Geneva, Switzerland and listed on the French stock market. ST ...
,
Renesas) founded the G3-PLC Alliance to promote G3-PLC technology. G3-PLC is the low layer protocol to enable large scale infrastructure on the electrical grid. G3-PLC may operate on CENELEC A band (35 to 91 kHz) or CENELEC B band (98 kHz to 122 kHz) in Europe , on ARIB band (155 kHz to 403 kHz) in Japan and on FCC (155 kHz to 487 kHz) for the US and the rest of the world. The technology used is
OFDM sampled at 400 kHz with adaptative modulation and tone mapping. Error detection and correction is made by both a
convolutional code
In telecommunication, a convolutional code is a type of error-correcting code that generates parity symbols via the sliding application of a boolean polynomial function to a data stream. The sliding application represents the 'convolution' of the ...
and
Reed-Solomon error correction. The required
media access control is taken from
IEEE 802.15.4
IEEE 802.15.4 is a technical standard which defines the operation of a low-rate wireless personal area network (LR-WPAN). It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, ...
, a radio standard. In the protocol,
6loWPAN has been chosen to adapt
IPv6
Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...
an internet network layer to constrained environments which is Power line communications.
6loWPAN integrates routing, based on the
mesh network
A mesh network is a local area network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate wit ...
LOADng, header compression, fragmentation and security. G3-PLC has been designed for extremely robust communication based on reliable and highly secured connections between devices, including crossing Medium Voltage to Low Voltage transformers. With the use of IPv6, G3-PLC enables communication between meters, grid actuators as well as smart objects. In December 2011, G3 PLC technology was recognised as an international standard at
ITU
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
in Geneva where it is referenced as G.9903, Narrowband orthogonal frequency division multiplexing power line communication transceivers for G3-PLC networks.
Transmitting radio programs
Sometimes PLC was used for transmitting radio programs over powerlines. When operated in the AM radio band, it is known as a
carrier current system.
High frequency (≥ 1 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.
Home networking (LAN)
Power line communications can also be used in a home to interconnect home computers and peripherals, and home entertainment devices that have an
Ethernet
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
port. Powerline adapter sets plug into power outlets to establish an Ethernet connection using the existing electrical wiring in the home (power strips with filtering may absorb the power line signal). This allows devices to share data without the inconvenience of running dedicated network cables.
The widely deployed powerline networking standard are fro
HD-PLC Allianceand
HomePlug Powerline Alliance. But HomePlug Powerline Alliance announced in October 2016 that it would wind down its activities, and the Alliance website (
Article title
/nowiki>) has been closed. HD-PLC, and HomePlug AV which is the most current of the HomePlug specifications were adopted by the IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
group as baseline technologies for their standard, published 30 December 2010. HomePlug estimates that over 45 million HomePlug devices have been deployed worldwide. Other companies and organizations back different specifications for power line home networking and these include the Universal Powerline Association
The Universal Powerline Association (UPA) was a trade association that covered power line communication (PLC) markets and applications. The UPA promoted and certified power line communication technology from 2004 to 2010.
History
An interest gr ...
, SiConnect, Xsilon, and the ITU-T
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Commu ...
's G.hn
G.hn is a specification for home networking with data rates up to 2 Gbit/s and operation over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. A single G.hn semiconductor device is able to net ...
specification.
Non-home networking (LAN)
With the diversification of IoT applications, the demand for high-speed data communication such as transmission of high-definition video data and/or high-frequent sensor data is increasing in the field of smart building, smart factory, smart city, etc. In such use cases, power line communication technologies can also be used and provides the same advantage of reusing existing cables.
HD-PLC has developed a multi-hop technology that can be used to build large-scale networks. In addition, the 4th-generation HD-PLC technology provides multiple channels, which enables high-speed and long-range communication by selecting the optimal channel.
Broadband over power line
Broadband over power line (BPL) is a system to transmit two-way data over existing AC MV (medium voltage) electrical distribution wiring, between transformers, and AC LV (low voltage) wiring between transformer and customer outlets (typically 100 to 240 V). This avoids the expense of a dedicated network of wires for data communication, and the expense of maintaining a dedicated network of antennas, radios and routers in wireless network.
BPL uses some of the same radio frequencies used for over-the-air radio systems. Modern BPL employs Wavelet-OFDM, FFT-OFDM, or frequency-hopping spread spectrum to avoid using those frequencies actually in use, though early pre-2010 BPL standards did not. The criticisms of BPL from this perspective are of pre-OPERA, pre-1905 standards.
The BPL OPERA standard is used primarily in Europe by ISPs. In North America it is used in some places (Washington Island, WI, for instance) but is more generally used by electric distribution utilities for smart meter
A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor. Smart meters communicate the information to the consumer for greater clarity of consumption beha ...
s and load management.
Since the ratification of the IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
(HD-PLC, HomePlug) LAN standard and its widespread implementation in mainstream router chipsets, the older BPL standards are not competitive for communication between AC outlets within a building, nor between the building and the transformer where MV meets LV lines.
Ultra-high frequency (≥100 MHz)
Even higher information rate transmissions over power line use RF through microwave frequencies transmitted via a transverse mode
A transverse mode of electromagnetic radiation is a particular electromagnetic field pattern of the radiation in the plane perpendicular (i.e., transverse) to the radiation's propagation direction. Transverse modes occur in radio waves and microwav ...
surface wave propagation mechanism that requires only a single conductor. An implementation of this technology is marketed as E-Line. These use microwaves instead of the lower frequency bands, up to 2–20 GHz. While these may interfere with radio astronomy
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming f ...
when used outdoors, the advantages of speeds competitive with fibre optic
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass (silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a means to ...
cables without new wiring are likely to outweigh that.
These systems claim symmetric and full duplex communication in excess of 1 Gbit/s in each direction. Multiple Wi-Fi channels with simultaneous analog television in the 2.4 and 5.0 GHz unlicensed bands have been demonstrated operating over a single medium voltage line conductor. Because the underlying propagation mode is extremely broadband
In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. ...
(in the technical sense), it can operate anywhere in the 20 MHz20 GHz region. Also since it is not restricted to below 80 MHz, as is the case for high-frequency BPL, these systems can avoid the interference issues associated with use of shared spectrum with other licensed or unlicensed services.
Standards
Two distinctly different sets of standards apply to powerline networking as of early 2010.
Within homes, the IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
standards specify how, globally, existing AC wires should be employed for data purposes. The IEEE 1901 includes HD-PLC and HomePlug AV as baseline technologies. Any IEEE 1901 products can coexist and be fully interoperable between products using the same technology. On the other hand, medium-frequency home control devices remain divided, although X10 tends to be dominant. For power grid use, IEEE has approved a low-frequency (≤ 500 kHz) standard called IEEE 1901.2 in 2013.
Standards organizations
Several competing organizations have developed specifications, including the HomePlug Powerline Alliance (defunct), Universal Powerline Association
The Universal Powerline Association (UPA) was a trade association that covered power line communication (PLC) markets and applications. The UPA promoted and certified power line communication technology from 2004 to 2010.
History
An interest gr ...
(defunct), an
HD-PLC Alliance
On October 2009, the ITU-T adopted Recommendation G.hn
G.hn is a specification for home networking with data rates up to 2 Gbit/s and operation over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. A single G.hn semiconductor device is able to net ...
/G.9960 as a standard of networks for high-speed powerline, coax, and phoneline communications. The National Energy Marketers Association (a US trade body) was also involved in advocating for standards.
In July 2009, the IEEE Power line Communication Standards Committee approved its draft standard for broadband over power lines. The IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
final standard was published on 30 December 2010, and included features from HomePlug and HD-PLC. Power line communication via IEEE 1901 and IEEE 1905 compliant devices is indicated by the nVoy certification all major vendors of such devices committed to in 2013. NIST
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
has included IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
(HD-PLC, HomePlug AV) and ITU-T
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU). It is responsible for coordinating standards for telecommunications and Information Commu ...
G.hn
G.hn is a specification for home networking with data rates up to 2 Gbit/s and operation over four types of legacy wires: telephone wiring, coaxial cables, power lines and plastic optical fiber. A single G.hn semiconductor device is able to net ...
as "Additional Standards Identified by NIST Subject to Further Review" for the Smart grid in the United States
Support for the smart grid in the United States became federal policy with passage of the Energy Independence and Security Act of 2007. The law set out $100 million in funding per fiscal year from 2008 to 2012, established a matching program to sta ...
. IEEE also came up with a low-frequency standard for long-distance smart grids called IEEE 1901.2 in 2013.[
]
See also
* HomePlug Powerline Alliance
* HomePNA
* IEEE 1901
The IEEE Std 1901-2010 is a standard for high speed (up to 500 Mbit/s at the physical layer) communication devices via electric power lines, often called broadband over power lines (BPL). The standard uses transmission frequencies below 100  ...
* IEEE 1675-2008
IEEE 1675-2008 was a standard for broadband over power lines developed by the IEEE Standards Association. It provided electric utility companies with a comprehensive standard for safely installing hardware required for Internet access capabili ...
* KNX (standard)
KNX is an open standard (see EN 50090, ISO/IEC 14543) for commercial and domestic building automation. KNX devices can manage lighting, blinds and shutters, HVAC, security systems, energy management, audio video, white goods, displays, remote ...
* List of broadband over power line deployments
This is a list of broadband over power line deployments. In this sense, "broadband" usually refers to Internet access using power line communication technology.
Active
* North America:
** United States: The United Telecom Council publishes the ...
* LonWorks
* Open Smart Grid Protocol
* Multimedia over Coax Alliance
The Multimedia over Coax Alliance (MoCA) is an international standards consortium that publishes specifications for networking over coaxial cable. The technology was originally developed to distribute IP television in homes using existing cab ...
* National Emergency Alarm Repeater
* Residential gateway
A residential gateway is a small consumer-grade gateway which bridges network access between connected local area network (LAN) hosts to a wide area network (WAN) (such as the Internet) via a modem, or directly connects to a WAN (as in EttH), whi ...
* Universal Powerline Association
The Universal Powerline Association (UPA) was a trade association that covered power line communication (PLC) markets and applications. The UPA promoted and certified power line communication technology from 2004 to 2010.
History
An interest gr ...
* IEC 61334 IEC 61334, known as Distribution automation using distribution line carrier systems, is a standard for low-speed reliable power line communications by electricity meters, water meters and SCADA.
It is also known as spread frequency-shift keying ( ...
* HD-PLC
References
Further reading
* Powerline Communication: Potential and Critical System, Existing Technologies and Prospects for Future Development http://www.tesionline.it/default/tesi.asp?idt=34078
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External links
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OSGP Alliance
European Telecommunications Standards Institute
{{Use dmy dates, date=June 2020
Computer networking
Internet access
Electrical grid
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