1. An electrical grid transports power from generation sources via transmission lines to distribution lines and customers. Power is stepped up for transmission and stepped down for distribution and customer use. 2. Key components of electrical grids include transformers, which increase or decrease voltage; insulators, which prevent current flow; circuit breakers, which interrupt current during faults; and conductors, which carry current. 3. Transformers use electromagnetic induction to transfer power between circuits without a direct connection, allowing voltage to be increased for transmission and decreased for distribution and end use.

1. Contant
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1. Transformer…………………………………………. 1
2. Insulator………………………………………………
3. Circuit Breaker……………………………………….
4. Relly………………………………………………….
5. Double concrete pole…………………………………
6. Conductor…………………………………………….
7. Step down transformer……………………………….

2. Introduction
Grid Power:-
An electrical grid is an interconnected network for delivering electricity from
producers to consumers. It consists of
 Generating stations that produceelectrical power
 high voltage transmission lines that carry power from distant sources to demand
centers
 Distribution lines that connectindividual customers.
Power stations may be located near a fuel source, at a dam site (to take advantage
of renewable energy sources), and are often located away from heavily populated
areas. The electric power which is generated is stepped up to a higher voltage at
which it connects to the electric power transmission net.
The bulk power transmission network will move the power long distances,
sometimes across international boundaries, until it reaches its wholesale customer
(usually the company that owns the local electric power distribution network).
On arrival at a substation, the power will be stepped down from a transmission
level voltage to a distribution level voltage. As it exits the substation, it enters the
distribution wiring. Finally, upon arrival at the service location, the power is
stepped down again from the distribution voltage to the required service voltage(s).
Electrical grids vary in size from covering a single building through national
grids which cover whole countries, to transnational grids which can cross
continents.
Although electrical grids are wide spread, 1.4 billion people are not connected to
an electricity grid
Electrical grids can be prone to malicious intrusion or attack; thus, there is a need
for electric grid security. Also as electric grids modernize and introduce computers,
cyber threats also start to become a security risk.

3. Fig:-1
Transformer:-
A transformer is a passive electrical device that transfers electrical energy between
two or more circuits through electromagnetic induction. A varying current in one
coil of the transformer produces a varying magnetic field, which in turn induces a
varying electromotive force (emf) or "voltage" in a second coil. Power can be
transferred between the two coils, without a metallic connection between the two
circuits. Faraday's law of induction discovered in 1831 described this effect.
Transformers are used to increase or decrease the alternating voltages in electric
power applications.
Fig:-2

4. Since the invention of the first constant-potential transformer in 1885, transformers
have become essential for the transmission, distribution, and utilization of
alternating current electrical energy. A wide range of transformer designs is
encountered in electronic and electric power applications. Transformers range in
size from RF transformers less than a cubic centimeter in volume to units
interconnecting the power gridweighing hundreds of tons.
Insulator:-
An electrical insulator is a material whose internal electric charges do not flow
freely; very little electric current will flow through it under the influence of
an electric field. This contrasts with other
materials, semiconductors and conductors, which conduct electric current more
easily. The property that distinguishes an insulator is its resistivity; insulators have
higher resistivity than semiconductors or conductors.
A perfect insulator does not exist, because even insulators contain small numbers
of mobile charges (charge carriers) which can carry current. In addition, all
insulators become electrically conductive when a sufficiently large voltage is
applied that the electric field tears electrons away from the atoms. This is known as
the breakdown voltage of an insulator. Some materials such
as glass, paper and Teflon, which have high resistivity, are very good electrical
insulators. A much larger class of materials, even though they may have lower bulk
resistivity, are still good enough to prevent significant current from flowing at
normally used voltages, and thus are employed as insulation for electrical
wiring and cables. Examples include rubber-like polymers and most plastics which
can be thermoset or thermoplastic in nature.
fig:-3

5. Circuit Breaker:-
A circuit breaker is an automatically operated electrical switch designed to protect
an electrical circuit from damage caused by excess current from an overload
or short circuit. Its basic function is to interrupt current flow after a fault is
detected. Unlike a fuse, which operates once and then must be replaced, a circuit
breaker can be reset (either manually or automatically) to resume normal
operation.
Circuit breakers are made in varying sizes, from small devices that protect low-
current circuits or individual household appliance, up to large switchgear designed
to protect high voltage circuits feeding an entire city. The generic function of a
circuit breaker, RCD or a fuse, as an automatic means of removing power from a
faulty system is often abbreviated as OCPD(Over Current Protection Device).
Fig:-4
Relay:-
A relay is an electrically operated switch. Many relays use an electromagnet to
mechanically operate a switch, but other operating principles are also used, such
as solid-state relays. Relays are used where it is necessary to control a circuit by a
separate low-power signal, or where several circuits must be controlled by one
signal. The first relays were used in long distance telegraph circuits as amplifiers:
they repeated the signal coming in from one circuit and re-transmitted it on another
circuit. Relays were used extensively in telephone exchanges and early computers
to perform logical operations.

6. A type of relay that can handle the high power required to directly control an
electric motor or other loads is called a contactor. Solid-state relayscontrol power
circuits with no moving parts, instead using a semiconductor device to perform
switching. Relays with calibrated operating characteristics and sometimes multiple
operating coils are used to protect electrical circuits from overload or faults; in
modern electric power systems these functions are performed by digital
instruments still called "protective relays".
Fig:-5
Double Concrete Pole:-
A utility pole is a column or post used to support overhead power lines and various
other public utilities, such as electrical cable, fiber optic cable, and related
equipment such as transformers and street lights. It can be referred to as
a transmission pole, telephone pole, telecommunication pole, power pole, hydro
pole,[1] telegraph pole, or telegraph post, depending on its application. A stobie
pole is a multi-purpose pole made of two steel joists held apart by a slab of
concrete in the middle, generally found in South Australia.
Electrical wires and cables are routed overhead on utility poles as an inexpensive
way to keep them insulated from the ground and out of the way of people and
vehicles. Utility poles can be made of wood, metal, concrete, or composites

7. like fiberglass. They are used for two different types of power
lines; subtransmission lines which carry higher voltage power between substations,
and distribution lines which distribute lower voltage power to customers.
The first poles were used in 1816 by the telegraph inventor Sir Francis
Ronalds who set up eight miles of overhead cable in Hammersmith. Utility poles
were first used in the mid-19th century in America with telegraph systems, starting
with Samuel Morse who attempted to bury a line
between Baltimore and Washington, D.C., but moved it above ground when this
system proved faulty. Today, underground distribution lines are increasingly used
as an alternative to utility poles in residential neighborhoods, due to poles'
perceived ugliness.
Fig:-6

8. Conductor:-
In physics and electrical engineering, a conductor is an object or type of material
that allows the flow of an electrical current in one or more directions. Materials
made of metal are common electrical conductors. Electrical current is generated by
the flow of negatively charged electrons, positively charged holes, and positive or
negative ions in some cases.
In order for current to flow, it is not necessary for one charged particle to travel
from the machine producing the current to that consuming it. Instead, the charged
particle simply needs to nudge its neighbor a finite amount who will nudge its
neighbor and on and on until a particle is nudged into the consumer, thus powering
the machine. Essentially what is occurring here is a long chain of momentum
transfer between mobile charge carriers; the Drude model of conduction describes
this process more rigorously. This momentum transfer model makes metal an ideal
choice for a conductor as metals, characteristically, possess a delocalized sea of
electrons which gives the electrons enough mobility to collide and thus effect a
momentum transfer.
As discussed above, electrons are the primary mover in metals; however, other
devices such as the cationic electrolyte(s) of a battery, or the mobile protons of
the proton conductor of a fuel cell rely on positive charge carriers. Insulators are
non-conducting materials with few mobile charges that support only
insignificant electric currents.
Fig:-7

9. Step down transformer:-
A Transformer is a static apparatus, with no moving parts, which transforms
electrical power from one circuit to another with changes in voltage and current
and no change in frequency. There are two types of transformers classified by their
function: Step up Transformer and Step down Transformer.
A Step up Transformer is a device which converts the low primary voltage to a
high secondary voltage i.e. it steps up the input voltage. A Step down Transformer
on the other hand, steps down the input voltage i.e. the secondary voltage is less
than the primary voltage.
The following images shows a simple demonstration of the use of Transformers
(both Step up and Step down Transformers) in a typical Transmission System.
Fig:-8
Principle of Working of a Transformer
An electrical transformer works on the principle of Mutual Induction, which states
that a uniform change in current in a coil will induce an E.M.F in the other coil
which is inductively coupled to the first coil.

10. In its basic form, a transformer consists of two coils with high mutual inductance
that are electrically separated but have common magnetic circuit. The following
image shows the basic construction of a Transformer.
How TransformerWorks?
The first set of the coil, which is called as the Primary Coil or Primary Winding, is
connected to an alternating voltage sourcecalled Primary Voltage.
The other coil, which is called as Secondary Coil or Secondary Winding, is
connected to the load and the load draws the resulting alternating voltage (stepped
up or stepped downvoltage).
The alternating voltage at the input excites the Primary Winding, an alternating
current circulates the winding. The alternating current will result in an alternating
magnetic flux, which passes through the iron magnetic core and completes its path.
Since the secondary winding is also linked to the alternating magnetic flux,
according to Faraday’s Law, an E.M.F is induced in the secondary winding. The

11. strength of the voltage at the secondary winding is dependent on the number of
windings through which the flux gets passed through.
Thus, without making an electrical contact, the alternating voltage in the primary
winding is transferred to the secondary winding.