How Power Transformers work ? | Epic 3D Animation #transformers
Summary
TLDRThis video explores the workings of power transformers, key devices in electrical energy transmission and distribution. It explains the basic principles of transformers, including electromagnetic induction, mutual induction, and the difference between step-up and step-down transformers. The video also covers transformer components such as windings, laminated cores, and bushings, and discusses efficiency improvements like minimizing eddy currents. Additionally, the video explains transformer types, the importance of transformer oil, and the role of tap changers in adjusting voltage levels during variable loads.
Takeaways
- ⚡ Transformers revolutionized the field of electrical energy transmission and distribution by enabling constant voltage AC supply systems.
- 🔌 Transformers work on the principle of electromagnetic induction, which occurs when a changing magnetic flux induces voltage in a nearby coil.
- 🔄 Transformers are static machines that increase or decrease voltage levels of an AC supply with a corresponding change in current.
- 💡 The primary winding of a transformer is connected to the supply, while the secondary winding delivers the output voltage.
- 🛠️ Transformers use ferromagnetic cores to improve efficiency by providing a low reluctance path for magnetic flux and minimizing leakage flux.
- 🔥 Laminated cores are employed in transformers to reduce energy losses caused by eddy currents, improving overall efficiency.
- 🔋 Step-up transformers increase voltage while lowering current, whereas step-down transformers decrease voltage and raise current.
- 🌐 Transformers do not change the frequency of the AC supply; the input and output frequency remain the same.
- ⚙️ On-load tap changers allow transformers to adjust voltage ratios to maintain stable output under varying load conditions.
- 🌡️ Transformers are filled with insulating oil for cooling and insulation, and a conservator tank is used to store excess oil.
Q & A
What is the primary function of a transformer?
-A transformer is used for increasing or decreasing the voltage levels of an AC supply with a corresponding change in current. It transfers electrical energy from one circuit to another through mutual induction.
Why do transformers not incur frictional or windage losses?
-Transformers do not have any moving parts, except for the on-load tap changer (OLTC) and motor drive unit, which minimizes frictional or windage losses. This makes them one of the most efficient electrical machines.
What principle does a transformer operate on?
-A transformer operates on the principle of mutual induction. When an alternating current (AC) flows through the primary coil, it produces a varying magnetic field that induces a voltage in the secondary coil.
Why doesn't electromagnetic induction work with a DC supply in transformers?
-Electromagnetic induction requires a change in magnetic flux to induce voltage. Since a DC supply generates a constant magnetic field without flux changes, no voltage is induced in the secondary coil.
What is the purpose of the transformer core?
-The transformer core provides a low reluctance path for the magnetic flux between the primary and secondary windings, making the transfer of electrical energy more efficient.
What are eddy currents and how are they minimized in a transformer?
-Eddy currents are loops of electric current induced in the transformer core due to the changing magnetic flux. They cause energy loss in the form of heat. To minimize them, laminated cores made of thin, insulated sheets are used.
What is the difference between a step-up and step-down transformer?
-A step-up transformer increases the voltage from the primary to the secondary winding, while a step-down transformer decreases the voltage from the primary to the secondary winding.
What role do tappings play in a transformer?
-Tappings are connection points along the winding that allow access to different portions of the coil, enabling voltage adjustments. They are used to fine-tune the transformer’s output voltage.
Why are power transformers designed with a laminated core?
-Power transformers use a laminated core to reduce eddy current losses. The insulation between the thin sheets of ferromagnetic material blocks the flow of eddy currents, enhancing efficiency.
What is the difference between single-phase and three-phase transformers?
-Single-phase transformers operate on single-phase AC supply and are typically used for low power applications like home electricity. Three-phase transformers operate on a three-phase AC supply and are used for high power applications like industrial power distribution.
Outlines
🔌 The Evolution of Transformers in Electrical Systems
The invention of transformers at the end of the 19th century revolutionized the way electrical energy is transmitted and distributed, making it possible for power stations to be located far from homes. Transformers operate at high voltages and handle large electrical loads. They increase or decrease AC voltage levels, with corresponding changes in current, and are highly efficient because they have no moving parts (except for the On Load Tap Changer). The working principle of transformers is based on electromagnetic induction, which occurs when a changing magnetic flux links with a coil, inducing voltage. This principle is at the core of transformer operation.
⚙️ The Role of Ferromagnetic Cores in Transformers
To improve the efficiency of energy transfer, transformer coils are wrapped around a ferromagnetic core, made of materials like iron or steel. These cores help link the magnetic flux between the primary and secondary windings. However, alternating magnetic flux also generates eddy currents in the core, causing heat loss. To reduce this, transformers use laminated cores, composed of insulated iron or steel sheets, which minimize eddy currents and energy loss. The transformer efficiently transfers electrical energy between voltage levels without converting it to another form.
⚡ Step-Up and Step-Down Transformers
Transformers adjust the input and output voltages according to their transformation ratio. If the secondary winding has more turns than the primary, it’s a step-up transformer, increasing voltage and lowering current. If the primary has more turns, it’s a step-down transformer, lowering voltage and increasing current. Importantly, transformers do not change the frequency of the AC supply. They also have tapping points along the windings to adjust the voltage ratio, enabling different output voltages.
🔄 Differences Between Core-Type and Shell-Type Transformers
While core-type transformers have windings around the core, shell-type transformers place windings within a laminated core. Both operate on the same principle of electromagnetic induction but differ in their structural design. Single-phase transformers are used for residential power, stepping down voltage from high transmission levels to household use. In contrast, three-phase transformers handle larger power loads and are preferred for high-power applications due to their efficiency in distributing power.
🔋 The Core: Heart of the Transformer
The transformer core, composed of laminated sheets, minimizes energy loss and noise caused by vibration. Windings are carefully insulated and placed to avoid damage from the core’s sharp edges. For large power transformers, the windings are separated by axial and radial spacers, which allow oil to flow for cooling and improve insulation. High-conductivity copper windings, often rectangular in shape, are used due to their stability and efficiency.
🔧 Helical and Continuous Disc Windings in Power Transformers
Low-voltage windings in power transformers often use helical winding for high-current applications, while high-voltage windings use continuous disc windings for uniform voltage distribution. Copper conductors are coated with insulation, and multiple strands of conductors are used to prevent eddy current losses. Transformers can use either star or delta configurations for windings, depending on their design.
⚙️ Adjusting Transformer Voltage: Tappings and On-Load Tap Changers
Transformers use tappings on the high-voltage winding to adjust the voltage ratio for efficient operation under varying loads. On-load tap changers allow switching between different tappings without interrupting the supply. These changers are operated mechanically, usually by a motor drive unit, and include a diverter switch and tap selector.
🏠 Bushings and Insulation in Transformers
Transformer bushings, both low-voltage and high-voltage, allow the safe transfer of current through the transformer tank. Low-voltage bushings are typically porcelain, while high-voltage bushings use more complex designs with oil-impregnated or resin-impregnated insulation. These bushings are vital for preventing electrical and mechanical stresses.
💡 The Role of Transformer Oil and Conservators
Transformer oil serves a dual purpose: providing electrical insulation and cooling the transformer windings. A conservator tank stores excess oil, ensuring that the transformer tank remains filled. This oil is crucial for the safe and efficient operation of power transformers, as a shortage could lead to transformer failure.
Mindmap
Keywords
💡Transformer
💡Electromagnetic Induction
💡Primary and Secondary Windings
💡Ferromagnetic Core
💡Eddy Currents
💡Step-up Transformer
💡Step-down Transformer
💡Leakage Flux
💡On-load Tap Changer
💡Insulating Oil
Highlights
Transformers revolutionized electrical energy transmission, enabling the development of modern AC supply systems.
Transformers operate at high voltages and can handle millions of watts of electrical load.
A transformer increases or decreases AC voltage levels with a corresponding inverse change in current.
Transformers have no moving parts, except for the On Load Tap Changer (OLTC), making them highly efficient.
The principle of electromagnetic induction is key to transformer operation: a changing magnetic flux induces voltage in coils.
AC supply creates alternating magnetic fields, enabling voltage induction through mutual induction between coils.
Ferromagnetic cores improve energy transfer efficiency by providing a low-reluctance path for magnetic flux.
Eddy currents cause energy loss in transformer cores; laminated cores minimize this by reducing eddy current formation.
Step-up transformers increase voltage with a decrease in current, while step-down transformers do the opposite.
Transformer tappings adjust the voltage ratio between primary and secondary windings, providing different output voltages.
Shell-type and core-type transformers have different structural designs but work on the same principle of electromagnetic induction.
Three-phase transformers are used for high-power applications due to their efficiency in transmitting large amounts of power.
Power transformers use a laminated core, insulation materials, and specialized windings to minimize losses and ensure safe operation.
Helical windings are used in low-voltage windings to handle high current in power transformers efficiently.
High-voltage bushings and oil-insulated transformers enhance voltage handling capacity and provide cooling for reliable operation.
Transcripts
Transformers are game changers in the
field of electrical energy transmission
and
distribution the invention of power
Transformers towards the end of the 19th
century made possible the development of
the modern constant voltage AC Supply
systems with power stations located many
miles away from our
homes this incredible machine operates
at hundreds of thousands of volts and
can handle millions of watt of
electrical load
in this video we are going to explore
the working of this incredible piece of
engineering so without further Ado let's
start it a Transformer is used for
increasing or decreasing the voltage
levels of a AC Supply with a
corresponding increase or decrease in
current it is a static machine which
means unlike an electric motor which has
a stationary part called the stator and
a moving part known as the rotor a
Transformer does not have any moving
parts except for the oltc and motor
Drive Unit which we will discuss later
in this video due to having no moving
Parts Transformers do not incur any
frictional or windage losses making them
one of the most efficient electrical
machines before diving into the working
of a power transformer let's first take
a look at the fundamentals of a
transformer when we move a magnet near a
coil a voltage is induced in the coil
this occur due to a change in the number
of magnetic field lines passing through
the coil or alternatively we can say
there is a change in magnetic flux
linking with the coil this phenomenon is
known as electromagnetic
induction the strength of induced
voltage depends upon the number of turns
in the coil the strength of the magnetic
field and how fast we are moving the
magnet or we can say the rate of change
of flux linking with the coil
a change in magnetic flux is absolutely
necessary for electromagnetic induction
if we stop moving the magnet no matter
how strong the magnetic field of the
magnet is or how many turns are there in
the coil no voltage is induced in the
coil let's replace this bar magnet with
another coil if we connect this coil to
a DC Supply the magnetic field produced
by the coil looks very similar to the
magnetic field of the bar
magnet as the magnetic flux linking with
the first coil is not changing with time
no voltage is induced in the first coil
that's why electromagnetic induction
does not work with a DC
Supply now instead of a DC Supply if we
feed an AC Supply to this coil an
alternating magnetic field is formed
this varying magnetic field creates a
change in the magnetic flux of the first
coil and hence hence a voltage is
induced in the first coil this is called
Mutual induction and it is the working
principle of a
transformer similar to this setup a
Transformer is consists of two coils
wrapped around a ferromagnetic
core these coils are made with copper
coated with a thin layer of varnish or
insulation the thickness of this coating
depends upon the desired level of
insulation required
varnish coating serves to insulate each
turn of the coil preventing any bypasses
and ensuring uninterrupted current flow
along the entire length of the
coil when either of the two coils is fed
with an AC Supply the alternating
magnetic field produced by that coil
links with the other coil inducing a
voltage however this transfer of
electrical energy is very inefficient
because only a small part of the
magnetic field from the first coil links
with the other
coil to improve efficiency coils are
wound around a core made of
ferromagnetic materials like iron or
steel the coil connected to the supply
is called the primary winding of the
Transformer and the coil on the output
side or connected to load is called the
secondary
winding the flux produced by the primary
winding which links with the secondary
winding is called linkage flux
while the flux produced by the primary
winding but not linking with a secondary
winding is called leakage flux it's
important to note that leakage flux does
not contribute to the transfer of
electrical energy and therefore should
be minimized to improve the efficiency
of a
transformer a Transformer core acts as a
pathway for magnetic flux providing a
low reluctance path as a result most of
the magnetic flux produced by the
primary coil link with secondary coil
making the transfer of electrical energy
more
efficient as the core is also made up of
conducting material the alternating flux
passing through the core induces Loops
of current inside the core due to
electromagnetic induction these Loops of
electric current are called Edy
currents Edy currents cause energy loss
inside the core in the form of heat
which reduces the efficiency of a
transformer that's why in a Transformer
a laminated core is used instead of a
solid ferromagnetic
core a laminated core is made up of thin
sheets of iron or steel each coated with
insulation these sheets are tightly held
together to minimize the air gap between
them the insulation on the sheets blocks
the flow of Eddie currents by providing
High Resistance thus minimizing their
formation
and that's how a laminated core
minimizes Eddy currents and makes the
transfer of energy more
efficient as we know an electric motor
is used to convert electrical energy
into mechanical
energy however a Transformer is
different it does not convert electrical
energy into any other form instead it
transfer electrical energy from one
voltage level to
another the input and output voltage of
a transformer are related according to
its transformation ratio here NP and ns
are number of turns in the primary and
secondary winding respectively if the
number of turns in the secondary winding
are higher than on the primary winding
the voltage induced in the secondary
winding is higher compared to the
primary input voltage while the current
in the secondary winding is lower
because energy is conserved this type of
Transformer is called a stepup
Transformer and it is used for
increasing the voltage level of an AC
Supply on the other hand if the primary
winding has more turns compared to the
secondary winding the voltage induced in
the secondary winding is lower than the
primary input voltage and the secondary
current is higher this type of
Transformer is called a stepdown
Transformer and it is used for
decreasing the voltage level of an AC
Supply
an important point to note is that a
Transformer does not affect the
frequency of the AC Supply the input and
output of the Transformer have different
voltages but the same
frequency now let's understand what are
Transformer tappings a tapping in a
Transformer is a connection point along
the winding that allow access to a
specific portion of the
coil tappings are used to adjust the
voltage ratio between the primary and
secondary windings enabling the
Transformer to provide different output
voltages based on how the primary and
secondary windings are placed around the
laminated core Transformers are
generally of two types core type
Transformers and shell type
Transformers as we have already
discussed core type Transformers let's
now focus on shell type
Transformers the working principle of a
shell type Transformer is the same as
that of a core type Transformer the only
difference is in their structure a shell
type Transformer also has primary and
secondary windings placed centrically on
a laminated ferromagnetic core in this
design the core surrounds a significant
portion of the
windings both core and shell type
Transformers can produce similar
characteristics the choice between core
and shell type construction is typically
determined by factors such as cost
insulation stress heat distribution and
weight both of these are singlephase
Transformers meaning they operate on a
singlephase AC supply singlephase
distribution Transformers are also a
integral part of power system these are
step down Transformers that reduce the
high voltage AC input from the nearest
substation to 120 or 240 volts which is
the voltage used in your
home high voltage singlephase AC input
is fed through HV bushings we will
discuss high voltage bushings in detail
later in this video it is a pole mounted
singlephase distribution transformer
meaning it is installed on electrical
poles and has a power rating of a few
100 KVA or less in contrast three-phase
Transformers are used for high power
applications a three-phase Transformer
operates on a three-phase AC Supply
which consists of three individual
phases with a phase difference of 120°
between each
phase the power ratings of three-phase
Transformers can reach hundreds of MVA
depending on the specific Transformer
and its design high power rating
Transformers typically work on a
three-phase supply instead of a
singlephase supply why because
three-phase systems are more efficient
for transmitting and distributing large
amount of power compared to a single
phase now that we've covered the basics
of Transformers let's dive into the
specifics of how a power transformer
operates let's start with the heart of a
transformer the core in any efficient
power transformer the core isn't just
important it's absolutely essential to
its operation without it nothing else
would work as it
should a power transformer core is built
from thousands of thin laminated sheets
made of ferromagnetic materials like
Silicon steel the purpose of Transformer
core is to provide a low reluctance path
for the magnetic flux that links primary
and secondary
windings the alternating flux which
links primary and secondary windings
causes vibration in the laminated sheets
generating loud unwanted noise and
leading to energy loss to minimize these
issues the laminated sheets are tightly
secured
together let's now focus on how the
windings are placed on a power
Transformers
core first an insulation sheet and an
insulation cylinder are placed to
insulate the windings from the core and
protect them from damage caused by the
core's sharp
edges this cylinder is made made from
electrical insulation
materials three pairs of low voltage and
high voltage windings are placed
centrically on each limb of the core in
a three-phase Transformer each pair of
low voltage and high voltage winding
corresponds to one phase the low voltage
winding is always placed near the core
because it has a low voltage rating
making it easier to insulate from the
core the winding arrangement of power
transformer also includes axial and
Radial
spacers axial and Radial spacers
typically made from insulating materials
like pressboard epoxy resin or other
high strength insulating
Composites they prevent winding
deformation under mechanical stress
ensuring long-term reliability and
performance these spacers provide proper
gaps or Ducks between different
conductors allowing Transformer oil to
flow and cool the windings
additionally axial and Radial spacers
ensure proper insulation and structural
Integrity Transformer windings are made
of high conductivity copper due to its
excellent mechanical properties and high
electrical conductivity making it an
ideal material for this
application for all Transformers with
ratings larger than a few KVA
rectangular section conductors are used
instead of the normal round
conductors this is because because
windings with rectangular section
conductors have a good space factor and
high mechanical
stability copper conductors are covered
with paper
insulation high power Transformers use
paper insulation instead of varnish or
enamel coating because paper insulation
can better withstand higher temperatures
without degrading provides greater
mechanical and dialectric strength
allowing it to endure high voltages
without
breakdown in a three-phase Transformer
each phase is consist of a pair of low
voltage and high voltage
windings in a low voltage winding the
number of turns are much less compared
to a high voltage winding as the name
suggests the voltage level in the LV
winding is lower than in the HV winding
and the current is very high according
to the transformation
ratio the exact voltage and current
ratings of the LV and HV winding depends
upon the specific
Transformer helical winding is mostly
used for low voltage windings in power
Transformers it's the simplest type of
winding and is ideal for low voltage
High current
applications in a helical winding the
conductor is shaped in the form of a
helix the amount of current in the LV
winding of a power transformer can be
thousands of amps which is why a very
thick conductor is used for the LV
winding however using a single solid
conductor can cause Eddie current losses
to mitigate this a continuously
transposed conductor is used in a low
voltage winding instead of a single
solid
conductor a CTC is consists of multiple
strands each insulated from the others
by varnish
Coating in a CTC the position of each
strand continuously changes along the
length of the cable
this prevents circulating currents
caused by differences in the induced
voltage of each
strand high voltage windings have a
greater number of turns compared to low
voltage windings although the conductor
cross-sectional area is significantly
smaller HV windings are typically wound
using continuous dis
windings in a continuous dis winding
conductors are wound in continuous
spirals alternating from inside to
outside and outside to inside forming
dis- like
structures these discs are connected
through inner and outer
crossovers The Continuous disk design
ensure more uniform voltage distribution
across the winding reducing the risk of
insulation
failure power transformer windings are
connected in either star or Delta
configuration depending on the design of
the
Transformer we will discuss about star
and Delta Connections in a future video
in a power transformer and support
structure made of insulating materials
like press board is used for providing
mechanical support and electrical
insulation crepe paper tubes and srbp
tubes are employed for ensuring secure
and effective
connections almost all power
Transformers require adjustment of their
voltage ratio to operate effectively
under variable load
conditions this is achieved by adjusting
their transformation ratio using
tappings tappings are placed on the high
voltage winding because high voltage
winding is more accessible as it is
positioned outside of the low voltage
winding Additionally the lower current
in the HV winding simplifies the process
of switching between different
tappings an onload tap changer is used
to switch between Taps to maintain the
output voltage of a transformer during
variable load
conditions it is consists of two main
parts a diverter switch and a tap
selector the operation of an onload tap
changer is mechanically operated by a
motor Drive Unit through a bevel gear
mechanism all of these components
including the core windings tappings and
on load tap changer are enclosed within
a sealed chamber known as the
transformer tank the terminals of the
low voltage and high voltage windings
are brought out of the transformer tank
through
bushings Transformer bushings are
essential components designed to
withstand High electrical and mechanical
stresses in a Transformer we have both
low voltage bushings and high voltage
bushings the bushings connected to the
low voltage windings are called Low volt
voltage bushings while those connected
to the high voltage windings are called
high voltage
bushings for low voltage windings simple
porcelain bushings are used a porcelain
bushing mainly consists of a central
conductor surrounded by a weather
resistant insulating structure made from
high dialectric strength ceramic
materials like
porcelain for the high voltage side oil
impregnated or resin impregnated
condenser bushings are used as they are
designed to withstand higher
voltages a condenser bushings consists
of a central conductor surrounded by a
condenser and a porcelain
insulator the condenser is made up of
layers of metal foil and insulation
paper impregnated with oil or resin this
Arrangement acts like numerous
capacitors connected in series this
configuration ensures a uniform
distribution of voltage within the
bushing these types of bushings are
filled with insulating mineral oil to
further enhance their voltage handling
capacity the top of the bushing includes
an oil expansion chamber to accommodate
the expansion and contraction of the oil
due to temperature
changes insulating oil is crucial to the
operation of a power
transformer the main tank of a power
transformer is completely filled with
insulating mineral oil known as
Transformer
oil this oil is stable and high
temperatures and possesses excellent
electrical insulating properties
providing both Cooling and insulation to
the Transformer
windings an additional smaller tank
known as the conservator is used to
store excess Transformer
oil the conservator is connected to the
transformer tank and ensures that it is
is always completely filled with oil
preventing any oil shortage inside the
transformer
tank Transformer oil is extremely
important for the insulation of a power
transformer and a shortage of oil in the
transformer tank can even lead to
Transformer
failure a power transformer is a large
and complex machine and there are still
many Concepts and devices related to it
that I haven't covered in this video If
you enjoy this type of content and found
this video helpful please subscribe to
my channel and give it a like
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