Prepayment meters

Prepayment meter and magnetic stripe tokens, from a rented accommodation in the UK. The button labeled A displays information and statistics such as current tariff and remaining credit. The button labeled B activates a small amount of emergency credit should the customer run out.
Prepayment meter and magnetic stripe tokens, from a rented accommodation in the UK. The button labeled A displays information and statistics such as current tariff and remaining credit. The button labeled B activates a small amount of emergency credit should the customer run out.

The standard business model of electricity retailing involves the electricity company billing the customer for the amount of energy used in the previous month or quarter. In some countries, if the retailer believes that the customer may not pay the bill, a prepayment meter may be installed. This requires the customer to make advance payment before electricity can be used. If the available credit is exhausted then the supply of electricity is cut off by a relay. Download high resolution version (1164x522, 72 KB) Electricity prepayment meter, and prepayment tokens. ... Download high resolution version (1164x522, 72 KB) Electricity prepayment meter, and prepayment tokens. ... Marcus Boltonas (Mark Boltan) Marcus Boltonas Brief history The magnetic stripe which is often reffered to as the Bolton is derived from the Marcus Boltonas from the Jurassic period. ... Automotive style miniature relay A relay is an electrical switch that opens and closes under the control of another electrical circuit. ...


In the UK, mechanical prepayment meters used to be common in rented accommodation. Disadvantages of these included the need for regular visits to remove cash, and risk of theft of the cash in the meter. For other uses, see Cash (disambiguation). ...


Modern solid-state electricity meters, in conjunction with smart card technology, have removed these disadvantages and such meters are commonly used for customers considered to be a poor credit risk. In the UK, one system is the PayPoint network, where rechargeable tokens (Quantum cards for natural gas, or plastic "keys" for electricity) can be loaded with whatever money the customer has available. Smart card used for health insurance in France. ... Credit risk is the risk of loss due to a debtors non-payment of a loan or other line of credit (either the principal or interest (coupon) or both). ... PayPoint is a broad term which can be used for different places where somebody can pay for numerous services. ...
Prepayment key
Prepayment key

A similar system, with 2 way communication smart cards, has been used for more than 1 million meters by Elektromed in Turkey. Image File history File links Metadata Size of this preview: 800 × 309 pixelsFull resolution (1668 × 644 pixel, file size: 109 KB, MIME type: image/jpeg) Electricity key meter - the user charges up the key in a shop and the money transfers to the meter. ... Image File history File links Metadata Size of this preview: 800 × 309 pixelsFull resolution (1668 × 644 pixel, file size: 109 KB, MIME type: image/jpeg) Electricity key meter - the user charges up the key in a shop and the money transfers to the meter. ...


In South Africa prepaid meters are recharged by entering a unique, encoded twenty digit number using a keypad. This makes the tokens, essentially a slip of paper, very cheap to produce.


Around the world, experiments are going on, especially in developing countries, to test pre-payment systems. In some cases, a lack of social acceptance has led to non-implementation of this technology.


There are various groups, such as the Standard Transfer Specification (STS) association, which promote common standards for prepayment metering systems across manufacturers. STS is a three-letter abbreviation with multiple meanings, including: Société de transport de Sherbrooke Space Transportation System, the official name for the United States Space Shuttle program sequence-tagged site, in genomics Silver thriosulphate or Silver thriosulfate, in chemistry Scanning tunneling spectroscopy Satanas, a Filipino-American gang Science...


Time of use metering

Time of Usage (TOU) metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to automatically control usage on the part of the customer (resulting in automatic load control), it is often simply the customers responsibility to control his own usage, or pay accordingly (voluntary load control). This also allows the utilities to plan their transmission infrastructure appropriately. A public utility is a company that maintains the infrastructure for a public service. ...


Power export metering
Many electricity customers are installing their own electricity generating equipment, whether for reasons of economy, redundancy or environmental reasons. When a customer is generating more electricity than required for his own use, the surplus may be exported back to the power grid. Net metering is a electricity policy for consumers who own, generally small, renewable energy facilities, such as wind or solar power, or uses vehicle-to-grid systems. ... Look up redundancy in Wiktionary, the free dictionary. ... Green energy is a term used by some environmentalists to describe what they deem to be environmentally friendly sources of power. ... Surplus means the quantity left over, after conducting an activity; the quantity which has not been used up, and can refer to: budget surplus, the opposite of a budget deficit economic surplus Surplus product or surplus value in Marxian economics physical surplus in the economic theory of Piero Sraffa Operating... Transmission towers Transmission lines in Lund, Sweden Electric power transmission, or more accurately Electrical energy transmission, is the second process in the delivery of electricity to consumers. ...


This exported energy may be accounted for in the simplest case by the meter running backwards during periods of net export, thus reducing the customer's recorded energy usage by the amount exported. Unless equipped with a detent or equivalent, a standard meter will accurately record power flow in each direction by simply running backwards when power is exported. Such meters are no longer legal in the UK but instead a meter capable of separately measuring imported and exported energy is required. Suppliers offer different rates for imported and exported electricity while meters that go backwards provides a different area of risk for the industry. Net metering is a electricity policy for consumers who own, generally small, renewable energy facilities, such as wind or solar power, or uses vehicle-to-grid systems. ...


In common use are renewable sources (e.g., wind turbines, photovoltaic cells), or gas or steam turbines, which are often applied in cogeneration systems. Another potential upload source that has been proposed is plug-in hybrid car batteries (vehicle-to-grid power systems). This requires a "smart grid," which includes meters that measure electricity via remote control and give customers timing and pricing options. Vehicle-to-grid systems could be installed at workplace parking lots and garages and at park and rides and could help drivers charge their batteries at home at night when off-peak power prices are cheaper, and receive bill crediting for selling excess electricity back to the grid during high-demand hours. This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... A solar cell, a form of photovoltaic cell, is a device that uses the photoelectric effect to generate electricity from light, thus generating solar power (energy). ... For other uses, see Gas (disambiguation). ... A Siemens steam turbine with the case opened. ... For other uses, see CHP. Cogeneration (also combined heat and power, CHP) is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat. ... Vehicle to Grid (V2G) technology is a bi-directional grid interface for gridable vehicles such as Battery Electric Vehicles and Plug-in Hybrid Electric Vehicles. ... A Smart meter generally refers to a type of advanced meter (usually an electrical meter) that identifies consumption in more detail than a conventional meter, and optionally communicates that information via some network back to the local utility for monitoring and billing purposes. ... This article does not cite any references or sources. ... a park-and-ride bus in Oxford Park and ride terminals are public transport stations that allow commuters to drive short distances in their personal automobiles to catch a ride on a bus or railroad system (usually classified as light rail or the heavier commuter rail). ... Energy demand management is also known as demand side management (DSM). ...


Ownership

Due to the deregulation of electricity supply markets in many countries, the company responsible for an electricity meter may not be obvious. Depending on the arrangements in place, the meter may be the property of the electricity distributor, the retailer or for some large users of electricity the meter may belong to the customer. Deregulation is the process by which governments remove, reduce, or simplify restrictions on business and individuals in order to (in theory) encourage the efficient operation of markets. ... 11kV/400V-230V transformer in an older suburb of Wellington, New Zealand Electricity distribution is the penultimate stage in the delivery (before retail) of electricity to end users. ... Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ...


The company responsible for reading the meter may not always be the company which owns it. Meter reading is now sometimes subcontracted and in some areas the same person may read gas, water and electricity meters at the same time. A residential gas meter of the usual diaphragm style A gas meter is used to measure the flow of fuel gases such as natural gas and propane. ... A typical residential water meter A water meter is a device used to measure water usage. ...


Location
Current transformers used as part of metering equipment for three-phase 400 A electricity supply. The fourth neutral wire does not require a current transformer because current cannot flow in this wire without also flowing in one of the three phase wires.
Current transformers used as part of metering equipment for three-phase 400 A electricity supply. The fourth neutral wire does not require a current transformer because current cannot flow in this wire without also flowing in one of the three phase wires.
Commercial power meter
Commercial power meter

The location of an electricity meter varies with each installation. Possible locations include on a power pylon serving the property, in a street-side cabinet or inside the premises adjacent to the consumer unit / distribution board. Electricity companies may prefer external locations as the meter can be read without gaining access to the premises but external meters may be more prone to vandalism. Current transformers used as part of metering equipment for three-phase 400Amp electricity supply. ... Current transformers used as part of metering equipment for three-phase 400Amp electricity supply. ... A CT for operation on a 110 kV grid A current transformer (CT) is a type of instrument transformer designed to provide a current in its secondary winding proportional to the current flowing in its primary. ... Three phase systems have 3 waveforms (usually carrying power) that are 2/3π radians (120 degrees,1/3 of a cycle) offset in time. ... Image File history File linksMetadata Download high-resolution version (3072x2048, 2587 KB) Power meter in the back of a Dunkin Donuts at a Framingham Rest Stop in Massachusetts. ... Image File history File linksMetadata Download high-resolution version (3072x2048, 2587 KB) Power meter in the back of a Dunkin Donuts at a Framingham Rest Stop in Massachusetts. ... For pylons of overhead lines, see Electricity pylon Pylon Noun from Greek πυλώνας gateway tower like structure, usually one of a series, used to support high voltage electricity cables. ... Wylex standard consumer unit fitted with rewirable fuses Modern Hager consumer unit fitted with MCBs and an RCD A consumer unit is a box of fuses or breakers, usually arranged in a single row. ... A fairly standard American circuit breaker panel manufactured by General Electric and using interchangeable circuit breakers A distribution board (known in the United States as a (circuit) breaker panel, panelboard, or load center or for old ones, fuse box) is a mounting enclosure for multiple electrical circuit breakers. ... Vandalism is the conspicuous defacement or destruction of a structure, a symbol or anything else that goes against the will of the owner/governing body. ...


Current transformers permit the meter to be located remotely from the current-carrying conductors. This is common in large installations. For example a substation serving a single large customer may have metering equipment installed in a cabinet, without bringing heavy cables into the cabinet. A 115 kV to 41. ...


Connection

In North America, it is common for smaller electricity meters to plug into a standardised socket. This allows the meter to be replaced without disturbing the wires to the socket. Some sockets may have a bypass while the meter is removed for service. The amount of electricity used without being recorded during this small time is considered insignificant when compared to the inconvenience which might be caused to the customer by cutting off the electricity supply.


In the UK, the supply and load terminals are normally provided in the meter housing itself, at least for smaller meters (up to around 100 A).


Tampering and security
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Meters can be manipulated so as to make them under-register, effectively allowing power use without paying for it. Image File history File links Question_book-3. ...


The enforcement actions enabled by modern anti-tampering meters are inexpensive compared to the revenue losses and public inconveniences they prevent. Power companies may install remote-reporting meters specifically to enable remote detection of tampering, and specifically to discover theft of energy.


When tampering is detected, the normal tactic, legal in most areas, is to switch the subscriber to a "tampering" tariff charged at the meter's maximum designed current. At US$ 0.095/KWh, a standard residential 50 A meter causes a legally collectible charge of about US$ 5,000.00 per month. Meter readers are trained to spot signs of tampering, and with crude mechanical meters, the maximum rate may be charged each billing period until the tamper is removed, or the service is disconnected.


A common method of tampering is to attach magnets to the outside of the meter. These act in addition to the braking magnets already installed in the meter, causing the meter to under-register. Rectified DC loads will not cause the meter to under-register the amount of power used to a significant degree, nor will a combination of capacitive and inductive load. An electricity meter registers real power (watts), not apparent power (VA); changing the reactive load has no effect on the meter. Similarly, a meter will not run backwards unless you are generating power and feeding it back on the grid from your house (and if detent equipped, will not run backward even then). This is called "net metering", and is commonly used where homeowners have photovoltaic or wind energy systems installed.


The owner of the meter normally secures the meter against tampering. Revenue meters mechanism and connections are sealed. Meters may also measure VAR-hours (the reflected load), neutral and DC currents (elevated by most electrical tampering), ambient magnetic fields, etc. Even simple mechanical meters can have mechanical flags that are dropped by magnetic tampering or large DC currents.


Newer computerized meters usually have counter-measures against tampering. AMR (Automated Meter Reading) meters often have sensors that can report opening of the meter cover, magnetic anomalies, extra clock setting, glued buttons, reversed or switched phases etc. These features are normally present in computerized meters.


Some fraud perpetrators bypass the meter, wholly or in part. This normally causes an increase in neutral current at the meter, which is detected and billed at normal rates by standard tamper-resistant meters.[citation needed] However, most residential meters in use in the United States are single-phase 240 volt meters that are coupled only to the energized lines with the neutral bypassing the meter entirely. This common setup is unable to detect neutral currents.


Even if the meter's neutral connector is completely disconnected, and the building's neutral is grounded to the phantom loop, causing an unsafe house or building, metering at the substation can alert the operator to tampering. Substations, interties and transformers normally have a high-accuracy meter for the area served. Power companies normally investigate discrepancies between the total billed and the total generated, in order to find and fix power distribution problems. These investigations are an effective method of discovering tampering. A phantom loop is an electrical network that uses part of the natural environment to complete a circuit. ...


In North America power thefts are often connected with indoor marijuana grow operations. Narcotics detectives associate abnormally high power usage with the lighting such operations require. Indoor marijuana growers aware of this are particularly motivated to steal electricity simply to conceal their usage of it. A grow-op is a short term for a marijuana grow operation in which cannabis plants are grown in a (usually domestic) setting, sometimes with the intent of creating large amounts of marijuana for commercial purposes. ...


The introduction of advanced meters in residential areas has produced additional privacy issues that may affect even ordinary customers. These meters are often capable of recording energy usage very frequently, usually once every 15 minutes or hour. In an IEEE research paper published in 1989, it was shown that readings of this sort can reveal information about the electrical loads being used within the home. A more detailed and recent analysis of this issue was performed by the Illinois Security Lab, as discussed on the Attested Metering project website. Automatic meter reading, or AMR, is the technology of automatically collecting data from water meter or energy metering devices (water, gas, electric) and transferring that data to a central database for billing and/or analyzing. ... The Illinois Security Lab is a research laboratory at the University of Illinois Urbana-Champaign established in 2004 to support research and education in computer and network security. ...

Multiple tariff (variable rate) meters

Electricity retailers may wish to charge customers different tariffs at different times of the day. This is because there is generally a surplus of electrical generation capacity at times of low demand, such as during the night (see supply and demand). Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ... The supply and demand model describes how prices vary as a result of a balance between product availability at each price (supply) and the desires of those with purchasing power at each price (demand). ...


Some multiple tariff meters use different tariffs for different amounts of demand. These are usually industrial meters.

Domestic usage

Domestic variable-rate meters normally only permit two tariffs ("peak" and "off-peak") and in such installations a simple electromechanical time switch may be used. They are commonly used in conjunction with electrical storage heaters. This article or section does not cite any references or sources. ...


Multiple tariffs are made easier by time of use (TOU) meters which incorporate or are connected to a time switch and which have multiple registers.


Switching between the tariffs may happen via a radio-activated switch rather than a time switch to prevent tampering with a sealed time switch to obtain cheaper electricity.

Radio-activated switching is common in the UK, with a nightly data signal sent within the longwave carrier of BBC Radio 4, 198 kHz. The time of off-peak usage is between 12.30am - 7.30am, and this is designed to power storage heaters and immersion heaters. In the UK, such tariffs are branded Economy 7 or White Meter. The popularity of such tariffs has declined in recent years, at least in the domestic market, due to the (perceived or real) deficiencies of storage heaters and the low cost of natural gas. This article or section does not cite any references or sources. ... A trio of propane water heaters. ... For other uses, see Natural gas (disambiguation). ...


Some meters using Economy 7 switch the entire electricity supply to the cheaper rate during the 7 hour night time period, not just the storage heater circuit. The downside of this is that the daytime rate will be a touch higher, and standing charges may be a little higher too. For instance, normal rate electricity may be 7p per kWh, whereas Economy 7's daytime rate might be 7.5p per kWh, but only 2.8p per kWh at night. Timer switches installed on washing machines, tumble dryers, dishwashers and immersion heaters may be set so that they switch on only when the rate is lower. Front-loading washing machine. ... An electric clothes dryer A clothes dryer or tumble dryer (also spelt with an i: drier) is a major household appliance that is used to remove the residual moisture from clothing or fabrics, generally shortly after being cleaned in a washing or washing/drying machine. ... A Dishwasher A two drawer DishDrawer dishwasher. ... A trio of propane water heaters. ...

Commercial usage

Large commercial and industrial premises may use electronic meters which record power usage in blocks of half an hour or less. This is because most electricity grids have demand surges throughout the day, and the power company may wish to give incentives to large customers to reduce demand at these times. These demand surges often corresponding to meal times or, famously, to advertisements in popular television programmes. A database query syntax error has occurred. ... A television program is the content of television broadcasting. ...


Multiple tariff rates may also dependend on frequency, also known as availability based tariff (ABT), deployed in Grid substations and inter-utility transfer points for bulk transfer of energy. This is based on the premise that the system frequency is inversely proportional to the current load. This also causes self-regulation because the rates are higher when the system frequency is low, eventually bringing down the demand.[citation needed]


Appliance energy meters

Plug in electricity meters (or "Plug load" meters) measure energy used by individual appliances. They can help in energy conservation by identifying major energy users, or devices that consume excessive standby power. Examples of plug in meters include various Kill A Watt and Watts Up[2] Meters. A power meter can often be borrowed from the local power authorities[3] or a local public library[4]. For the physical concepts, see conservation of energy and energy efficiency. ... Standby power, also called Vampire power, refers to the electric power consumed by electronic appliances while in a standby mode. ...


In-home energy use displays

A potentially powerful means to reduce household energy consumption is to provide real-time feedback to homeowners so they can change their energy using behavior. Recently, low-cost energy feedback displays, such as The Energy Detective or wattson[5], have become available. A study of a similar device deployed in 500 Ontario homes by Hydro One showed an average 6.5% drop in total electricity use when compared with a similarly sized control group.[6]

Design

As in the block diagram, the meter has a power supply, a metering engine, A processing and communication engine i.e a microcontroller, other add-on modules such as RTC, LCD display, communication ports/modules etc. Image File history File links Download high resolution version (637x747, 82 KB) Summary Basic Block Diagram of an Electronic Energy Meter. ... Image File history File links Download high resolution version (637x747, 82 KB) Summary Basic Block Diagram of an Electronic Energy Meter. ...

Metering engine

The metering engine is given the voltage and current inputs and has a voltage reference, samplers and quantisers followed by an ADC section to yield the digitised equivalents of all the inputs. These inputs are then processed using a Digital Signal Processor to calculate the various metering parameters such as powers, energies etc.


The largest source of long-term errors in the meter is drift in the preamp, followed by the precision of the voltage reference. Both of these vary with temperature as well, and vary wildly because most meters are outdoors. Characterizing and compensating for these is a major part of meter design.

Processing and communication section

This section has the responsibility of calculating the various derived quantities from the digital values generated by the metering engine. This also has the responsibility of communication using various protocols and interface with other addon modules connected as slaves to it.

RTC and other add-on modules

These are attached as slaves to the processing and communication section for various input/output functions. On a modern meter most if not all of this will be implemented inside the microprocessor, such as the Real Time Clock (RTC), LCD controller, temperature sensor, memory and analog to digital converters.

Solid state meters

Some newer electricity meters are solid state and display the power used on an LCD, while newer electronic meters can be read automatically. In physics, the solid state is one of the three phases of matter (solid, liquid, and gas). ... LCD redirects here. ...


In addition to measuring electricity used, solid state meters can also record other parameters of the load and supply such as maximum demand, power factor and reactive power used etc. They can also include electronic clock mechanisms to compute a value, rather than an amount, of electricity consumed, with the pricing varying of by the time of day, day of week, and seasonally.


Technology

Most solid-state meters use a current transformer to measure the current. This means that the main current-carrying conductors need not pass through the meter itself and so the meter can be located remotely from the main current-carrying conductors, which is a particular advantage in large-power installations. It is also possible to use remote current transformers with electromechanical meters though this is less common. Image File history File linksMetadata Download high resolution version (808x960, 155 KB) Summary Solid state electricity meter in a home in Holland. ... Image File history File linksMetadata Download high resolution version (808x960, 155 KB) Summary Solid state electricity meter in a home in Holland. ... A CT for operation on a 110 kV grid A current transformer (CT) is a type of instrument transformer designed to provide a current in its secondary winding proportional to the current flowing in its primary. ...


Historically, rotating meters could report their power information remotely, using a pair of contact closures attached to a KYZ line. In this scheme, line "K" is attached to two single-pole single-throw switches "Y" and "Z". "Y" and "Z" open and close as the meter's disk rotates. As the meter rotates in one direction, Y closes, then Z closes, then Y opens, then Z opens. When it rotates in the opposite direction, showing export of power, the sequence reverses. KYZ outputs were historically attached to "totalizer relays" feeding a "totalizer" so that many meters could be read all at once in one place.


KYZ outputs are also the normal historical way of attaching electric meters to programmable logic controllers, HVACs or other control systems. Some modern meters also supply interfaces to PLCs, or a contact closure that warns when the meter detects a demand near a higher tariff. PLC & input/output arrangements A programmable logic controller (PLC), or programmable controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. ... This article does not cite any references or sources. ... PLC may stand for: Palestinian Legislative Council, law-making body of the Palestinian Authority Parti Libéral du Canada, the term in French for the Liberal Party of Canada Partido Liberal Constitucionalista (or Constitutional Liberal Party), a major political party in Nicaragua Phospholipase C Platoon Leaders Class Polish-Lithuanian Commonwealth...

Communication technologies

High end electronic meters may now be equipped with a range of communication technologies including Low Power Radio, GSM, GPRS, Bluetooth, IrDA apart from the now conventional RS-232 and RS-485 wired link. They now store the entire usage profiles with time stamps and relay them at a click of a button. The demand readings stored with the profiles accurately indicate the load requirements of the customer. This load profile data is processed at the utilities and renders itself to a variety of representations, all sorts of graphs, reports et el. Remote meter reading is an application of telemetry. Often, meters designed for semi-automated reading have a serial port on that communicates by infrared LED through the faceplate of the meter. In some apartment buildings, a similar protocol is used, but in a wired bus using a serial current loop to connect all the meters to a single plug. The plug is often near the mailboxes. For other uses, see GSM (disambiguation). ... General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... The initials IRDA can refer to various things: In Information Technology and Communications, IrDA refers to Infrared Data Association, a standard for communication between devices (such as computers, PDAs and mobile phones) over short distances using infrared signals. ... RS-232 (also referred to as EIA RS-232C or V.24) is a standard for serial binary data interchange between a DTE (Data terminal equipment) and a DCE (Data communication equipment). ... EIA-485 (formerly RS-485 or RS485) is an electrical specification of a two-wire, half-duplex, multipoint serial connection. ... In electronics, a load profile is a graph of the changes in the electrical load on an electrical device versus time. ... Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. ... A male DE-9 connector used for a serial port on a PC style computer. ... For other uses, see Infrared (disambiguation). ... A male DE-9 connector used for a serial port on a PC style computer. ... A current loop describes two different electrical signalling schemes. ...


In the European Union, the most common infrared and protocol is "FLAG", a simplified subset of mode C of IEC 61107. In the U.S. and Canada, the favoured infrared protocol is ANSI C12.18. Some industrial meters use a protocol for programmable logic controllers. The most modern protocol proposed for this purpose is DLM/COSEM which can operate over any medium, including serial ports. The data can be transmitted by Zigbee, WiFi, telephone lines or over the power lines themselves. Some meters can be read over the internet. IEC 61107, formerly called IEC 1107 or FLAG is an international standard document that describes a widely-used computer protocol used to read utility metres in the European Union. ... PLC & input/output arrangements A programmable logic controller (PLC), or programmable controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. ... IEC 62056, also called DLM/COSEM is an internatinoal standard document that describes a computer protocol used to read utility metres in the European Union. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Wi-Fi (or Wi-fi, WiFi, Wifi, wifi), short for Wireless Fidelity, is a set of standards for wireless local area networks (WLAN) currently based on the IEEE 802. ... A telephone line (or just line) is a single-user circuit on a telephone communications system. ... For other uses, see Power band. ...

Automatic reading

AMR (Automatic Meter Reading) and RMR (Remote Meter Reading) describe various systems that allow meters to be checked by without the need to send a meter reader out. This can be effectively achieved using off-site metering, that is an electronic meter is placed at the junction point where all the connections originate, inaccessible to the end-user, and it relays the readings via the AMR technology to the utility.

Modern electricity meters

Operates by continuously measuring the instantaneous voltage (volts) and current (amperes) and finding the product of these to give instantaneous electrical power (watts) which is then integrated against time to give energy used (joules, kilowatt-hours etc). The meters fall into two basic categories, electromechanical and electronic. Download high resolution version (700x762, 56 KB)photograph of mechanism of an electrical induction meter (kilo-watt hour meter) Image taken by me Ali@gwc. ... Download high resolution version (700x762, 56 KB)photograph of mechanism of an electrical induction meter (kilo-watt hour meter) Image taken by me Ali@gwc. ... Image File history File linksMetadata Download high resolution version (2272x1704, 837 KB) Summary Close-up photo of a mechanical electricity meter; Note how every other dial turns anticlockwise. ... Image File history File linksMetadata Download high resolution version (2272x1704, 837 KB) Summary Close-up photo of a mechanical electricity meter; Note how every other dial turns anticlockwise. ... Download high resolution version (450x640, 47 KB)Three-phase electromechanical induction electricity meter, metering 100A 230/400V supply. ... Download high resolution version (450x640, 47 KB)Three-phase electromechanical induction electricity meter, metering 100A 230/400V supply. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Josephson junction array chip developed by NIST as a standard volt. ... This box: Electric current is the flow (movement) of electric charge. ... For other uses, see Ampere (disambiguation). ... For delivered electrical power, see Electrical power industry. ... For other uses, see Watt (disambiguation). ... This article is about the concept of integrals in calculus. ... The joule (symbol J, also called newton metre, or coulomb volt) is the SI unit of energy and work. ...


Electromechanical meters

The most common type of electricity meter is the Thomson or electromechanical induction watt-hour meter, invented by Elihu Thomson in 1888.[1][2] In engineering, electromechanics combines electromagnetism and mechanics. ... Look up induction in Wiktionary, the free dictionary. ... Elihu Thomson (March 29, 1853 - March 13, 1937) was an engineer who was instrumental in the founding of major electrical companies in the United States, Britain and France. ...

Technology

The electromechanical induction meter operates by counting the revolutions of an aluminium disc which is made to rotate at a speed proportional to the power. The number of revolutions is thus proportional to the energy usage. It consumes a small amount of power, typically around 2 watts. For magnetic induction, see Magnetic field. ... Aluminum redirects here. ...


The metallic disc is acted upon by two coils. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees using a lag coil. [1]This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and voltage. A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc - this acts as a brake which causes the disc to stop spinning when power stops being drawn rather than allowing it to spin faster and faster. This causes the disc to rotate at a speed proportional to the power being used. An induction coil or spark coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. ... Magnetic flux, represented by the Greek letter Φ (phi), is a measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... This box: Electric current is the flow (movement) of electric charge. ... As the circular plate moves down through a small region of constant magnetic field directed into the page, eddy currents are induced in the plate. ... For other uses, see Force (disambiguation). ... Magnetic lines of force of a bar magnet shown by iron filings on paper A magnet is an object that has a magnetic field. ... Angular velocity describes the speed of rotation and the orientation of the instantaneous axis about which the rotation occurs. ... This article is about the vehicle component. ... This article is about proportionality, the mathematical relation. ...


The type of meter described above is used on a single-phase AC supply. Different phase configurations use additional voltage and current coils. In electrical engineering, single-phase electric power refers to the distribution of electric power using a system in which all the voltages of the supply vary in unison. ... City lights viewed in a motion blurred exposure. ... A polyphase system is a means of distributing alternating current electrical power. ...

Reading

The aluminium disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of energy used. The dials may be of the cyclometer type, an odometer-like display that is easy to read where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. It should be noted that with the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism. For other uses, see Gear (disambiguation). ... In mathematics and computer science, a numerical digit is a symbol, e. ...


The amount of energy represented by one revolution of the disc is denoted by the symbol Kh which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the value of Kh, one can determine their power consumption at any given time by timing the disc with a stopwatch. If the time in seconds taken by the disc to complete one revolution is t, then the power in watts is P = 3600 × Kh / t. For example, if Kh = 7.2, as above, and one revolution took place in 14.4 seconds, the power is 1800 watts. This method can be used to determine the power consumption of household devices by switching them on one by one.


Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter. Electricity retailing is the final process in the delivery of electricity from generation to the consumer. ... For other uses, see Telephone (disambiguation). ... For other uses, see Mail (disambiguation). ...

Accuracy

In an induction type meter, creep is a phenomenon that can adversely affect accuracy, that occurs when the meter disc rotates continuously with potential applied and the load terminals open circuited. A creep test is when the meter is tested for the error due to creep.

Mechanism of electromechanical induction meter. (1) - Voltage coil - many turns of fine wire encased in plastic, connected in parallel with load. (2) - Current coil - three turns of thick wire, connected in series with load. (3) - Stator - concentrates and confines magnetic field. (4) - Aluminium rotor disc. (5) - rotor brake magnets. (6) - spindle with worm gear. (7) - display dials - note that the 1/10, 10 and 1000 dials rotate clockwise while the 1, 100 and 10000 dials rotate counter-clockwise.

Unit of measurement

The most common unit of measurement on the electricity meter is the kilowatt hour, which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules. Some electricity companies use the SI megajoule instead. Panel-mounted solid-state electricity meter, connected to 2MVA three-phase electricity substation. ... Panel-mounted solid-state electricity meter, connected to 2MVA three-phase electricity substation. ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... Usually hidden to the unaided eye, the 60Hz blinking of (non-incandescent) lighting powered by AC mains is revealed in this motion-blurred long exposure of city lights. ... A 115 kV to 41. ... For other uses, see Modem (disambiguation). ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ... The kilowatt-hour (symbol: kW·h) is a unit for measuring energy. ... The kilowatt (symbol: kW) is a unit for measuring power, equal to one thousand watts. ... The hour (symbol: h) is a unit of time. ... The joule (IPA: or ) (symbol: J) is the SI unit of energy. ... Look up si, Si, SI in Wiktionary, the free dictionary. ... A megajoule (abbreviation: MJ) is a unit of energy equal to 1000000 joules. ...


Demand is normally measured in watts, but averaged over a period, most often a quarter or half hour.


Reactive power is measured in "Volt-amperes reactive", (VARh) in kilovar-hours. A "lagging" or inductive load, such as a motor, will have negative reactive power. A "leading", or capacitive load, will have positive reactive power. Reactive power is an abstract quantity, typically used by power engineers to describe a certain type of energy flow in an electric distribution system. ... volt-amperes reactive (VAR): In alternating-current power transmission and distribution, the product of the rms voltage and current, the apparent power, multiplied by the sine of the phase angle between the voltage and the current. ... An electric current i flowing around a circuit produces a magnetic field and hence a magnetic flux Φ through the circuit. ... Various types of capacitors A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ...


Volt-amperes measures all power passed through a distribution network, including reactive and actual. This is equal to the product of root-mean-square volts and amperes.


Distortion of the electric current by loads is measured in several ways. Power factor is the ratio of resistive (or real power) to volt-amperes. A capacitive load has a leading power factor, and an inductive load has a lagging power factor. A purely resistive load (such as a fillament lamp, heater or kettle) exhibits a power factor of 1. Current harmonics are a measure of distortion of the wave form. For example, electronic loads such as computer power supplies draw their current at the voltage peak to fill their internal storage elements. This can lead to a significant voltage drop near the supply voltage peak which shows as a flattening of the voltage waveform. This flattening causes odd harmonics which are not permissible if they exceed specific limits, as they are not only wasteful, but may interfere with the operation of other equipment. Harmonic emissions are mandated by law in EU and other countries to fall within specified limits. The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power, and is a number between 0 and 1. ...

Other units of measurement

In addition to metering based on the amount of energy used, other types of metering are available.


Meters which measured the amount of charge (coulombs) used, known as ampere-hour meters, were used in the early days of electrification. These were dependent upon the supply voltage remaining constant for accurate measurement of energy usage, which was not a likely circumstance with most supplies. The coulomb (symbol: C) is the SI unit of electric charge. ... An ampere-hour (abbreviated as Ah or A-h) is a unit of electric charge. ...


Some meters measured only the length of time for which current flowed, with no measurement of the magnitude of voltage or current being made. These were only suited for constant load applications.


Neither type is likely to be used today.