ELECTRIFICACTION

INTRODUCTION
Electrification is the process of powering by electricity and is usually associated
with changing over from another power source.
BENEFITS OF ELECTRIC LIGHTING
Electric lighting was highly desirable. The light was much brighter than oil or gas lamps, and there
was no soot. Although early electricity was very expensive compared to today, it was far cheaper and
more convenient than oil or gas lighting. Electric lighting was so much safer than oil or gas that some
companies were able to pay for the electricity with the insurance savings.
PRE-ELECTRIC POWER
"One of the inventions most important to a class of highly skilled workers engineers! would be a
small motive power " ranging perhaps from the force of from half a man to that of two horses, which
might commence as well as cease its action at a moment#s notice, re$uire no expense of time for its
management and be of modest cost both in original cost and in daily expense." %harles &abbage,
'()'
To be efficient steam engines needed to be several hundred horsepower. *team engines and boilers
also re$uired operators and maintenance. +or these reasons the smallest commercial steam engines
were about , horsepower. This was above the need for many small shops. Also, a small steam
engine and boiler cost about -.,/// while an old blind horse that could develop '0, horsepower cost
-,/ or less. 1achinery to use horses for power cost -2// or less.
.1any power re$uirements were less than that of a horse. *hop machines, such as woodworking
lathes, were often powered with a one or two man crank. 3ousehold sewing machines were powered
with a foot treadle4 however, factory sewing machines were steam powered from a line shaft. 5ogs
were sometimes used on machines such as a treadmill, which could be adapted to churn butter.
6n the late '7th century specially designed power buildings leased space to small shops. These
building supplied power to the tenants from a steam engine through line shafts.
Electric motors were several times more efficient than small steam engines because central station
generation were more efficient than small steam engines and because line shafts and belts had high
friction losses.
Electric motors were more efficient than human or animal power. The conversion efficiency for animal
feed to work is between 8 and )9 compared to over 2/9 for electricity generated using coal
ECONOMIC IMPACT OF ELECTRIFICATION
+rom '(./"(/ each man"hour was provided with .)) hp. 6n '7)/ each man"hour was provided with
) hp, or a 29 annual increase, declining to '.)9 from '72/")/ The period of electrification of
factories and households from '7// to '78/, was one of high productivity and economic growth. 6n
economics, the efficiency of electrical generation has been shown to correlate with technological
progress.
FANS
A mechanical fan is a machine used to create flow within a fluid, typically a gas such as air. The fan
consists of a rotating arrangement of vanes or blades which act on the air. The rotating assembly of
blades and hub is known as an impeller, a rotor, or a runner. :sually, it is contained within some form
of housing or case.
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This may direct the airflow or increase safety by preventing ob=ects from
contacting the fan blades. 1ost fans are powered by electric motors, but other sources of power may
be used, including hydraulic motors andinternal combustion engines. +ans produce air flows with high
volume and low pressure although higher than ambient pressure!, as opposed to compressors which
produce high pressures at a comparatively low volume. A fan blade will often rotate when exposed to
an air stream, and devices that take advantage of this, such as anemometers and wind turbines,
often have designs similar to that of a fan.
Typical applications include climate control and personal thermal comfort e.g., an electric table or
floor fan!, vehicle and machinery cooling systems, ventilation, fume extraction ,winnowing e.g.,
separating chaff of cereal grains!, removing dust e.g. in a vacuum cleaner!, drying usually in
combination with heat! and to provide draft for a fire. >hile fans are often used to cool people, they
do not actually cool air if anything, electric fans warm it slightly due to the warming of their motors!,
but work by evaporative cooling of sweat and increased heat convection into the surrounding air due
to the airflow from the fans. Thus, fans may become ineffective at cooling the body if the surrounding
air is near body temperature and contains high humidity. 6n addition to their utilitarian function, vintage
or anti$ue fans, and in particular electric fans manufactured from the late '7th century through the
'7)/s, have become a recogni?ed collectible category
Types of fans
Wall Moune!
E"#aus Fans Ce$l$n% Fans
Ta&le fans
Ele'($'al Layou - )
Ele'($'al Layou - *
Ele'($'al Layou + ,
AMPERE
The ampere *6 unit symbol@ A4 *6 dimension symbol@ 6!, often shortened to amp is the *6 unit
of electric current $uantity symbol@ 6, i!< and is one of the seven*6 base units. 6t is named after AndrA"
1arie AmpBre '..)C'(2D!, +rench mathematician and physicist, considered the father of
electrodynamics.
6n practical terms, the ampere is a measure of the amount of electric charge passing a point in an
electric circuit per unit time, with D.,8'E'/'( electronsor one coulomb! per second constituting one
ampere.
The practical definition may lead to confusion with the definition of the coulombi.e., ' ampere"
second! and the ampere"hour AFh!, but amperes can be viewed as measuring a flow rate, the
number of charged! particles transiting per unit time, and coulombs simply as an amount, the total
number of particles.
T#e A-pe(e Is Na-e! Afe( An!(e Ma($e A-pe(e. F(en'# P#ys$'$s /)001-)2,345
1 AMP $s use! &as$'ally fo( $ns(u-ens o( %a!%es #a a(e s-all o( (e6u$(e a
s-all a-oun of ele'($'$y fo( #e(e ope(a$ons
)1 AMP $s use! &as$'ally fo( $ns(u-ens o( %a!%es #a a(e la(%e o( (e6u$(e
#$%# a-oun of ele'($'$y fo( #e(e ope(a$ons
1 a-p so'7es )1 a-p so'7es
INVERTER
A power inverter, or inverter, is an electronic device or circuitry that changes direct current 5%!
to alternating current A%!.
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The input voltage, output voltage and fre$uency, and overall power handling depend on the design of
the specific device or circuitry. The inverter does not produce any power4 the power is provided by the
5% source.
A power inverter can be entirely electronic or may be a combination of mechanical effects such as a
rotary apparatus! and electronic circuitry. Static inverters do not use moving parts in the conversion
process.
Typical applications for power inverters include@
Gortable consumer devices that allow the user to connect a battery, or set of batteries, to the
device to produce A% power to run various electrical items such as lights, televisions, kitchen
appliances, car batteries, and power tools.
:se in power generation systems such as electric utility companies or solar generating systems
to convert 5% power to A% power.
:se within any larger electronic system where an engineering need exists for deriving an A%
source from a 5% source.
INPT V!"T#$E
A typical power inverter device or circuit re$uires a relatively stable %& power source capable of
supplying enough current for the intended power demands of the system. The input voltage depends
on the design and purpose of the inverter. Examples include@
', H5%, for smaller consumer and commercial inverters that typically run from a rechargeable
',H lead acid battery.
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,8 and 8( H5%, which are common standards for home energy systems.
,// to 8// H5%, when power is from photovoltaic solar panels.
2// to 8)/ H5%, when power is from electric vehicle battery packs in vehicle"to"grid systems.
!utput waveform
An inverter can produce a s$uare wave, modified sine wave, pulsed sine wave, or sine wave
depending on circuit design. The two dominant commerciali?ed waveform types of inverters as of
,//. are modified sine wave and sine wave.
There are two basic designs for producing household plug"in voltage from a lower"voltage 5% source,
the first of which uses a switching boost converter to produce a higher"voltage 5% and then converts
to A%. The second method converts 5% to A% at battery level and uses a line"
fre$uency transformer to create the output voltage.
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S'#RE (#VE
This is one of the simplest waveforms an inverter design can produce and is useful for some
applications.
SINE (#VE
A power inverter device which produces a smooth sinusoidal A% waveform is referred to as a sine wave inverter.
To more clearly distinguish from "modified sine wave" or other creative terminology, the phrase pure
sine wave inverter is sometimes used.
6n situations involving power inverter devices which substitute for standard line power, a sine wave
output is extremely desirable because the vast ma=ority of electric plugs in products and appliances
are engineered to work well with the standard electric utility power which is a true sine wave.
At present, sine wave inverters tend to be more complex and have significantly higher cost than a modified sine
wave type of the same power handling.
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)IST!R*
+rom the late nineteenth century through the middle of the twentieth century, 5%"to"A% power
conversion was accomplished using rotary converters or motor"generator sets 1"I sets!. 6n the early
twentieth century, vacuum tubes and gas filled tubes began to be used as switches in inverter circuits.
The most widely used type of tube was the thyratron.
The origins of electromechanical inverters explain the source of the term inverter. Early A%"to"5%
converters used an induction or synchronous A% motor direct"connected to a generator dynamo! so
that the generator#s commutator reversed its connections at exactly the right moments to produce 5%.
A later development is the synchronous converter, in which the motor and generator windings are
combined into one armature, with slip rings
at one end and a commutator at the other and only one field frame. The result with either is A%"in,
5%"out. >ith an 1"I set, the 5% can be considered to be separately generated from the A%4 with a
synchronous converter, in a certain sense it can be considered to be "mechanically rectified A%".
Iiven the right auxiliary and control e$uipment, an 1"I set or rotary converter can be "run
backwards", converting 5% to A%. 3ence an inverter is an inverted converter.
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E"E&TRI& $ENER#T!R
6n electricity generation, an electric generator is a device that converts mechanical
energy to electrical energy. A generator forces electric current to flow through an external circuit. The
source of mechanical energy may be a reciprocating or turbine steam engine, water falling through
a turbine or waterwheel, an internal combustion engine, a wind turbine,
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a hand crank, compressed
air, or any other source of mechanical energy. Ienerators provide nearly all of the power for electric
power grids.
The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and
motors and generators have many similarities. 1any motors can be mechanically driven to generate
electricity and fre$uently make acceptable generators.
%*N#+!
A dynamo is an electrical generator that produces direct current with the use of acommutator.
5ynamos were the first electrical generators capable of delivering power for industry, and the
foundation upon which many other later electric"power conversion devices were based, including
the electric motor, the alternating"current alternator, and the rotary converter. Today, the simpler
alternator dominates large scale power generation, for efficiency, reliability and cost reasons. A
dynamo has the disadvantages of a mechanical commutator. Also, converting alternating to direct
current using power rectification devices vacuum tube or more recently solid state! is effective and
usually economic.
#"TERN#T!R
>ithout a commutator, a dynamo becomes an alternator, which is a synchronous singly fed
generator. Alternators producealternating current with a fre$uency that is based on the rotational
speed of the rotor and the number of magnetic poles.
Automotive alternators produce a varying fre$uency that changes with engine speed, which is then
converted by a rectifier to 5%. &y comparison, alternators used to feed an electric power grid must
operate at a speed determined by the fre$uency of the interconnecting grid. *ome devices such
as incandescent lamps and ballast"operated fluorescent lamps do not re$uire a constant fre$uency,
but synchronous motors such as in electric wall clocks do re$uire a constant grid fre$uency.
>hen attached to a larger electric grid with other alternators, an alternator will dynamically interact
with the fre$uency already present on the grid, and operate at a speed that matches the grid
fre$uency. 6f no driving power is applied, the alternator will continue to spin at a constant speed
anyway, driven as a synchronous motor by the grid fre$uency. 6t is usually necessary for an alternator
to be accelerated up to the correct speed and phase alignment before connecting to the grid, as any
mismatch in fre$uency will cause the alternator to act as a synchronous motor, and suddenly leap to
the correct phase alignment as it absorbs a large inrush current from the grid, which may damage the
rotor and other e$uipment.
Typical alternators use a rotating field winding excited with direct current, and a stationary stator!
winding that produces alternating current. *ince the rotor field only re$uires a tiny fraction of the
power generated by the machine, the brushes for the field contact can be relatively small. 6n the case
of a brushless exciter, no brushes are used at all and the rotor shaft carries rectifiers to excite the
main field winding.
IN%&TI!N $ENER#T!R
An induction generator or asynchronous generator is a type of A% electrical generator that uses the
principles of induction motors to produce power. 6nduction generators operate by mechanically turning
their rotor faster than the synchronous speed, giving negative slip. A regular A% asynchronous motor
usually can be used as a generator, without any internal modifications. 6nduction generators are
useful in applications such as minihydro power plants, wind turbines, or in reducing high"pressure gas
streams to lower pressure, because they can recover energy with relatively simple controls.
To operate an induction generator must be excited with a leading voltage4 this is usually done by
connection to an electrical grid, or sometimes they are self"excited by using phase correcting
capacitors.
+)% $ENER#T!R
A magnetohydrodynamic generator directly extracts electric power from moving hot gases through a
magnetic field, without the use of rotating electromagnetic machinery. 135 generators were originally
developed because the output of a plasma 135 generator is a flame, well able to heat the boilers of
a steam power plant. The first practical design was the AH%O 1k. ,), developed in '7D). The :.*.
government funded substantial development, culminating in a ,) 1> demonstration plant in '7(.. 6n
the *oviet :nion from '7., until the late '7(/s, the 135 plant : ,) was in regular commercial
operation on the 1oscow power system with a rating of ,) 1>, the largest 135 plant rating in the
world at that time.
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135 generators operated as a topping cycle are currently ,//.! less efficient
than combined cycle gas turbines.
!T)ER R!T#TIN$ E"E&TR!+#$NETI& $ENER#T!RS
Other types of generators, such as the asynchronous or induction singly fed generator, the doubly fed
generator, or thebrushless wound"rotor doubly fed generator, do not incorporate permanent magnets
or field windings that establish a constant magnetic field, and as a result, are seeing success in
variable speed constant fre$uency applications, such as wind turbines or other renewable energy
technologies.
The full output performance of any generator can be optimi?ed with electronic control but only
the doubly fed generators or the brushless wound"rotor doubly fed generator incorporate electronic
control with power ratings that are substantially less than the power output of the generator under
control, a feature which, by itself, offers cost, reliability and efficiency benefits.
)!+!P!"#R $ENER#T!
A homopolar generator is a 5% electrical generator comprising an electrically conductive disc or
cylinder rotating in a plane perpendicular to a uniform static magnetic field. A potential difference is
created between the center of the disc and the rim or ends of the cylinder!, the electrical
polarity depending on the direction of rotation and the orientation of the field.
6t is also known as a unipolar generator, acyclic generator, dis, dynamo, or -araday disc. The
voltage is typically low, on the order of a few volts in the case of small demonstration models, but
large research generators can produce hundreds of volts, and some systems have multiple
generators in series to produce an even larger voltage.
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They are unusual in that they can produce
tremendous electric current, some more than a million amperes, because the homopolar generator
can be made to have very low internal resistance.
E.&IT#TI!N
An electric generator or electric motor that uses field coils rather than permanent magnets re$uires a
current to be present in the field coils for the device to be able to work. 6f the field coils are not
powered, the rotor in a generator can spin without producing any usable electrical energy, while the
rotor of a motor may not spin at all.
*maller generators are sometimes self-excited, which means the field coils are powered by the
current produced by the generator itself. The field coils are connected in series or parallel with the
armature winding. >hen the generator first starts to turn, the small amount of remanent
magnetism present in the iron core provides a magnetic field to get it started, generating a small
current in the armature. This flows through the field coils, creating a larger magnetic field which
generates a larger armature current. This "bootstrap" process continues until the magnetic field in the
core levels off due tosaturation and the generator reaches a steady state power output.
Hery large power station generators often utili?e a separate smaller generator to excite the field coils
of the larger. 6n the event of a severe widespread power outage where islanding of power stations has
occurred, the stations may need to perform a black start to excite the fields of their largest generators,
in order to restore customer power service.
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There are two
types of
generators, one is ac generator and other is dc generator. Whatever may be the types of generators,
it always converts mechanical power to electrical power. An ac generator produces alternating power.
A DC generator produces direct power. Both of these generators produce electrical power, based on
same fundamental principle of Faraday's law of electromagnetic induction. According to these law,
when an conductor moves in a magnetic feldit cuts magnetic lines force, due to which an emf is
induced in the conductor. The magnitude of this induced emf depends upon the rate of change of fux
(magnetic line force) linkage with the conductor. This emf will cause an electric current to fow if the
conductor circuit is closed.
Hence the most basic tow essential parts of a generator are
a) a magnetic feld and
b) conductors which move inside that magnetic feld.
E"E&TRI&#" /N&TI!N 0!.
An electrical =unction box is a container for electrical connections, usually intended to conceal them
from sight and deter tampering. A small metal or plastic =unction box may form part of an electrical
conduit orthermoplastic"sheathed cable TG*! wiring system in a building. 6f designed for surface
mounting, it is used mostly in ceilings, under floors or concealed behind an access panel " particularly
in domestic or commercial buildings. An appropriate type such as that shown on the right! may be
buried in the plaster of a wall although full concealment is no longer allowed by modern codes and
standards! or cast into concrete " with only the cover visible. 6t sometimes includes in"built terminals
for the =oining of wires.
A similar, usually wall mounted, container used mainly to accommodate switches. sockets and the
associated connecting wiring is called a pattress. The term =unction box may also be used for a larger
item, such as a piece of street furniture. 6n the :J, such items are often called a cabinet.
*ee Enclosure electrical!. Kunction boxes form an integral part of a circuit protection system
where circuit integrity has to be provided, as for emergency lighting or emergency power lines, or the
wiring between a nuclear reactor and a control room. 6n such an installation, thefireproofing around
the incoming or outgoing cables must also be extended to cover the =unction box to prevent short
circuits inside the box during an accidental fire.
E"E&TRI&IT* +ETER
An electricity meter, electric meter, or energy meter is a device that measures the amount of electric
energy consumed by a residence, business, or an electrically powered device.
Electric utilities use electric meters installed at customers premises to measure electric energy
delivered to their customers for billing purposes. They are typically calibrated in billing units, the most
common one being the kilowatt hour ;kWh<. They are usually read once each billing period.
6n settings when energy savings during certain periods are desired, meters may measure demand,
the maximum use of power in some interval. "Time of day" metering allows electric rates to be
changed during a day, to record usage during peak high"cost periods and off"peak, lower"cost,
periods. Also, in some areas meters have relays for demand response load shedding during peak
load periods.
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NITS !- +E#SRE+ENTS
The most common unit of measurement on the electricity meter is the kilowatt hour;kWh<, which is
e$ual to the amount of energy used by a load of one kilowatt over a period of one hour, or
2,D//,/// =oules. *ome electricity companies use the *6 mega=oule instead.
5emand is normally measured in watts, but averaged over a period, most often a $uarter or half hour.
Leactive power is measured in "thousands of volt"ampere reactive"hours", kvarh!. &y convention, a
"lagging" or inductive load, such as a motor, will have positive reactive power. A "leading",
or capacitive load, will have negative reactive power.
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Holt"amperes measures all power passed through a distribution network, including reactive and
actual. This is e$ual to the product of root"mean"s$uare volts and amperes.
5istortion of the electric current by loads is measured in several ways. Gower factoris the ratio of
resistive or real power! to volt"amperes. A capacitive load has a leading power factor, and an
inductive load has a lagging power factor. A purely resistive load such as a filament lamp, heater or
kettle! exhibits a power factor of '. %urrent harmonics are a measure of distortion of the wave form.
+or example, electronic loads such as computer power supplies draw their current at the voltage peak
to fill their internal storage elements. This can lead to a significant voltage drop near the supply
voltage peak which shows as a flattening of the voltage waveform. This flattening causes odd
harmonics which are not permissible if they exceed specific limits, as they are not only wasteful, but
may interfere with the operation of other e$uipment. 3armonic emissions are mandated by law in E:
and other countries to fall within specified limits.
Electricity meters operate by continuously measuring the instantaneous voltagevolts!
and current amperes! to give energy used in =oules, kilowatt"hours etc.!. 1eters for smaller services
such as small residential customers! can be connected directly in"line between source and customer.
+or larger loads, more than about ,// ampere of load, current transformers are used, so that the
meter can be located other than in line with the service conductors. The meters fall into two basic
categories, electromechanical and electronic.
E"E&TR!+E&)#NI&#" +ETERS
The most common type of electricity meter is the electromechanical induction watt"hour meter.
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The electromechanical induction meter operates by counting the revolutions of a non"magnetic, but
electrically
conductive, metal disc which is made to rotate at a speed proportional to the power passing through
the meter. The number of revolutions is thus proportional to the energy usage. The voltage coil
consumes a small and relatively constant amount of power, typically around , watts which is not
registered on the meter. The current coil similarly consumes a small amount of power in proportion to
the s$uare of the current flowing through it, typically up to a couple of watts at full load, which is
registered on the meter.
The disc is acted upon by two sets of coils, which form, in effect, a two phaseinduction motor. One
coil is connected in such a way that it produces a magnetic fluxin proportion to the voltage and the
other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by
7/ degrees, due to the coil#s inductive nature, and calibrated using a lag coil.
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This produces eddy
currents in the disc and the effect is such that a force is exerted on the disc in proportion to the
product of the instantaneous current, voltage and phase angle power factor! between them.
A permanent magnet exerts an opposing force proportional to the speed of rotation of the disc. The
e$uilibrium between these two opposing forces results in the disc rotating at a speed proportional to
the power or rate of energy usage. The disc drives a register mechanism which counts revolutions,
much like the odometer in a car, in order to render a measurement of the total energy used.
The type of meter described above is used on a single"phase A% supply. 5ifferent phase
configurations use additional voltage and current coils.
The 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. >ith the
dial pointer type, ad=acent pointers generally rotate in opposite directions due to the gearing
mechanism.
The amount of energy represented by one revolution of the disc is denoted by the symbol Jh which is
given in units of watt"hours per revolution. The value .., is commonly seen. :sing the value of Jh
one can determine their power consumption at any given time by timing the disc with a stopwatch.
E"E&TR!NI& +ETERS
Electronic meters display the energy used on an M%5 or ME5 display, and some can also transmit
readings to remote places. 6n addition to measuring energy used, electronic meters can also record
other parameters of the load and supply such as instantaneous and maximum rate of usage
demands, voltages, power factor and reactive power used etc. They can also support time"of"day
billing, for example, recording the amount of energy used during on"peak and off"peak hours.
+"TIP"E T#RI-- 1V#RI#0"E R#TE2 +ETERS
Electricity retailers may wish to charge customers different tariffs at different times of the day to better
reflect the costs of generation and transmission. *ince it is typically not cost effective to store
significant amounts of electricity during a period of low demand for use during a period of high
demand, costs will vary significantly depending on the time of day. Mow cost generation capacity
baseload! such as nuclear can take many hours to start, meaning a surplus in times of low demand,
whereas high cost but flexible generating capacity such as gas turbines! must be kept available to
respond at a moment#s notice spinning reserve! to peak demand, perhaps being used for a few
minutes per day, which is very expensive.
*ome multiple tariff meters use different tariffs for different amounts of demand. These are usually
industrial meters.
%!+ESTI& S#$E
5omestic variable"rate meters generally permit two to three tariffs "peak", "off"peak" and "shoulder"!
and in such installations a simple electromechanical time switch may be used. 3istorically, these have
often been used in con=unction with electrical storage heaters or hot water storage systems.
1ultiple tariffs are made easier by time of use TO:! meters which incorporate or are connected to
a time switch and which have multiple registers.
*witching between the tariffs may happen via a radio"activated switch rather than a time switch to
prevent tampering with a sealed time switch to obtain cheaper electricity.
&!++ER&I#" S#$E
Marge 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 price incentives to large customers to reduce
demand at these times. These demand surges often correspond to meal times or, famously, to
advertisements interrupting popular television programmers.
#PP"I#N&E ENER$* +ETERS
Glug in electricity meters or "Glug load" meters! measure energy used by individual appliances.
There are a variety of models available on the market today but they all work on the same basic
principle. The meter is plugged into an outlet, and the appliance to be measured is plugged into the
meter. *uch meters can help in energy conservation by identifying ma=or energy users, or devices
that consume excessive standby power. >eb resources can also be used, if an estimate of the power
consumption is enough for the research purposes. A power meter can often be borrowed from the
local power authorities or a local public library.
IN3)!+E ENER$* SE %ISP"#*
A potentially powerful means to reduce household energy consumption is to provide convenient real"
time feedback to users so they can change their energy using behavior. Lecently, low"cost energy
feedback displays have become available. A study using a consumer"readable meter in )// Ontario
homes by Hydro One showed an average D.)9 drop in total electricity use when compared with a
similarly si?ed control group. Hydro One subse$uently offered free power monitors to 2/,///
customers based on the success of the pilot.Gro=ects such as Ioogle Gower1eter, take information
from a smart meter and make it more readily available to users to help encourage conservation.
S+#RT +ETERS
*mart meters go a step further than simple A1L automatic meter reading!. They offer additional
functionality including a real"time or near real"time reads, power outage notification, and power $uality
monitoring. They allow price setting agencies to introduce different prices for consumption based on
the time of day and the season.
These price differences can be used to reduce peaks in demand load shifting or peak lopping!,
reducing the need for additional power plants and in particular the higher polluting and costly to
operate natural gas powered peaker plants The feedback they provide to consumers has also been
shown to cut overall energy consumption
Another type of smart meter uses non intrusive load monitoring to automatically determine the
number and type of appliances in a residence, how much energy each uses and when. This meter is
used by electric utilities to do surveys of energy use. 6t eliminates the need to put timers on all of the
appliances in a house to determine how much energy each uses.
T#+PERIN$
1eters can be manipulated to make them under"register, effectively allowing power use without
paying for it. This theft or fraud can be dangerous as well as dishonest.
Gower companies often install remote"reporting meters specifically to enable remote detection of
tampering, and specifically to discover energy theft. The change to smart power meters is useful to
stop energy theft.
>hen tampering is detected, the normal tactic, legal in most areas of the :*A, is to switch the
subscriber to a "tampering" tariff charged at the meter#s maximum designed current. At :*-
/./7)0k>h, a standard residential )/ A meter causes a legally collectible charge of about :*-
),///.// per month. 1eter 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 on mechanical disk meters is to attach magnets to the outside of the
meter. *trong magnets saturate the magnetic fields in the meter so that the motor portion of a
mechanical meter does not operate. Mower power magnets can add to the drag resistance of the
internal disk resistance magnets. 1agnets can also saturate current transformers or power"supply
transformers in electronic meters, though countermeasures are common.
Lectified 5% loads cause mechanical but not electronic! meters to under"register. 5% current does
not cause the coils to make eddy currents in the disk, so this causes reduced rotation and a lower bill.
*ome combinations of capacitive and inductive load can interact with the coils and mass of a rotor
and cause reduced or reverse motion.
All of these effects can be detected by the electric company, and many modern meters can detect or
compensate for them.
The owner of the meter normally secures the meter against tampering. Levenue meters# mechanisms
and connections are sealed. 1eters may also measure HAL"hours the reflected load!, neutral and
5% 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 5%
currents.
Newer computeri?ed meters usually have counter"measures against tampering. A1L Automated
1eter Leading! meters often have sensors that can report opening of the meter cover, magnetic
anomalies, extra clock setting, glued buttons, inverted installation, reversed or switched phases etc.
*ome tampers bypass the meter, wholly or in part. *afe tampers of this type normally increase the
neutral current at the meter. 1ost split"phase residential meters in the :nited *tates are unable to
detect neutral currents. 3owever, modern tamper"resistant meters can detect and bill it at standard
rates.
5isconnecting a meter#s neutral connector is unsafe because shorts can then pass through people or
e$uipment rather than a metallic ground to the generator or earth.