Download Introduction HV

Books
This one we will
follow in the class
Books
This one we will
follow in the class
Books
This lineman is safely
supported by
polypropylene chains
for placement on live
400kV conductor.
This one is written by a lawyer
who invented a noble technique
of dropping a human being on a
live high tension line.
Books
Another good book
Books
This one is written by
my professor and his
professor, useful for
advanced learners.
Books
Another book for
advanced learners.
What is high voltage

A mobile phone is operated from a 4V
battery. It may be destroyed if anyone
attempts to operate it from a 12V car
battery.
Therefore 12V is quite a high voltage for a
mobile phone.
What is high voltage
230kV
230kV
High voltage is specially
referred
to
Step up
230kV
transformer is
electrical power system.
used to rise the
Step
 down
transformer is
used to reduce
the voltage to
33kV
Long transmission line used to
carry the power to Dhaka
33kV
Step down
transformer is
used to reduce
the voltage to
11kV
voltage to 132kV
or 230kV
At Kaptai we
generate at 11kV
or 21kV
11kV
11kV
Another Step down transformer
is used to reduce the voltage
further to 400V suitable for end
user.
400V
230V
Domestic users get electricity at
230Volt.
What is high voltage
Below 11kV : Low voltage
 11kV – 100kV : HV (high Voltage)
 100kV – 400kV : VHV (Very high voltage)
 400kV and above : EHV ( Extra high voltage)
 UHV : Ultra high voltage

Loss
NewinLoss in
transmission
transmission
2R,
line = Iline
2R=4I2R lines to be
is the
resistance
Basically it is requiredRfor
transmission
(2I)
of the line.
able to transmit more power
over the same line.
Kaptai
Why high voltage
Dhaka
I2I
Therefore we conclude that it is not
Equation for
I
I
wise to increase the line current
tois
power
transmit more power over a line,
P= V I Cos 
keeping the voltage same.
Loss in
transmission
line = I2R,
is the
resistance
Basically it is requiredRfor
transmission
lines to be
of the line.
able to transmit more power
over the same line.
Kaptai
Why high voltage
Dhaka
I
I
2V
Therefore we see that if the transmission
Equation for
Transformer
line voltage is increased it is power
capable
is of
transmitting
more power without
V
P= V I Cos 
increasing the power loss in the line.
I
I
Generator
Trends in voltage growth
Ac voltage
Unfortunately it is
a very old data.
Students
In our country
theare
highest requested
operating to
voltage isupdate
230kV.it.
We may realize our
position related to
the global trend.
Trends in voltage growth
dc voltage
Unfortunately
In our country we
HVDC transmission
not have
has been do
proven
to any
HVDC
be less attractive
to
the power transmission
system
system so far.
engineers.
Fields of applications of HV
•
•
•
•
Power system engineering
Research laboratories
IndustriesInterested
Nuclear research, particle
students
may
find
accelerators
new areas
of
• Electrostatic
precipitators
application
of coils
HV
• Automobile
ignition
• Medical applications like X-ray
machine
What we learn in
High Voltage
Engineering
• Testing of HV equipments like
power transformers, bushings,
CB, insulators, cables etc.
• Usually tests are done at a
voltage much higher than the
operating voltage.
• Generation, measurement and
control of different types of HV.
What we learn in
High Voltage
Engineering
• Failure mechanism of HV equipments
caused by HV stress.
• Breakdown mechanism of different types
of insulating materials ( solid, liquid, gas,
vacuum) under different types of voltages
(ac, dc, li, si).
• Computer simulation of HV systems so as
to (i) forecast before causing actual
breakdown (ii) Provide guideline towards
improved design.
• Provide technical assistance toward
designing HV equipments to be operated at
further higher voltages.
Few future prospects
of HV
• For cosmopolitan cities overhead
distributionInterested
lines are not allowed any
more. HV
underground
cables of
students
may add
compact size is the solution.
new
names fix-and-forget
to this
• Compact
all-in-one
type
GIS substations
are required in near
list.
future.
• HV has some residential and industrial
applications like water treatment plant,
insect killer/repeller, exhaust air
purifier etc.
ac High Voltage
?
Suppose it is said that the
voltage is 100kV.
Then this peak value is
=100 X 103 X 2 volt
Voltage
In
kV
?
10 ms
 140kV
In high voltage engineering,
we should always be careful
100kV
about the peak value power
of the
ac
frequency
voltage
voltage, because this isacthe
maximum voltage in the
system and may be responsible
Time
for initiating breakdown or
In
ms
failure.
dc High Voltage100kV
Voltage
In
kV
?
100kV
dc voltage
Time
In
ms
Lightning Impulse
Voltage
In 90%
kV
500kV
li
50%
10%
t0
t1
Is there any
Bangladesh
t2standard
Wave front
=1.25(t2-t1)
?
?
500k
V
American
standard is
1.5/40 µS
Standard li
1/50 µS
AsTime
per BSS &
In
μs ISS
t3
Wave tail
=t3-t0
Switching Impulse
?
500k
V
Voltage
In 90%
kV
500kV
li
50%
Standard si
250/2500,
Time
120/1000
µS
10%
t0
t1
t2
Wave front
=1.25(t2-t1)
t3
In
μs
Wave tail
=t3-t0
Course outline
Course No. EEE 471
Course Title : High Voltage Engineering
High Voltage dc : Rectifier circuits, Voltage multipliers, Van-de-graff
generator.
High Voltage ac : Cascaded transformers and Tesla coils.
Impulse Voltage : Shapes, mathematical analysis, codes and
standards, single and multistage impulse generators, tripping and
control of impulse generators.
Breakdown in gas, liquid and solid dielectric materials.
Corona.
High Voltage measurement and testing.
Over voltage phenomena and insulation co-ordination.
Lightning and switching surges, basic insulation level,
surge diverters and arresters.