Hkdmd

1. Manmohan
Memorial
Polytechnic
Approved by Council forTechnical
education andVocationalTraining
(CTEVT)

2. Vacuum Circuit
Breaker
Submitted To:​
Diploma in Electrical Engineering
Presented By: Group 'F'
Anil Sah​
Armendra Gupta​
Bideshwar Sah​
Grishma Niraula​
Navin Yadav​
Rajshree Malla Thakuri​
Saroj Kumar Yadav
04
07
09
16
23
32
39

3. Acknowledge
Manmohan
Memorial
Polytechnic
1
Er. Binod Ghimire
2
Staff of Manmohan
Memorial
Polytechnic Campus
3

4. Table of
Contents
Introduction of Circuit Breaker
Vacuum Circuit Breaker
Main objectives ofVCB
Introduction ofVacuum Circuit Breaker
Construction of VCB
Working of VCB
Block diagram of VCB
General Parts of VCB
Advantages And Disadvantages ofVCB
Application and Use ofVCB
Comparison
Estimation and Costing of VCB
Conclusion

5. Introduction
of Circuit
Breaker
Automatically protect the Electrical
Circuit
ADS (Automatic Disconnection of
Supply
Switch ON and OFF electric circuit
on Power transmission and
Distribution networks

6. Vacuum Circuit
Breaker
 UsedVacuum as the arc extinction medium
 Fixed and moving contact is enclosed in a
permanently sealed vacuum interrupter
 Used for Medium voltage (11 kV to 33 kV)
 High insulating medium for arc extinciton
 Dielectric strength increases up to a rate of
thousands time as compared to other breakers
 More efficient, Less Bulky and Cheaper cost

7. Main
objectives
of the
project
 To quench arc during zero current
crossing by establishing high dielectric
strength in the contact.
 When failure occurs in any part of the
system, it must be quickly detected and
disconnected from the system.
 To protect an electrical circuit from
damage caused by overload or, short
circuit.

8. Introduction
of Vacuum
Circuit
Breaker
AVacuum circuit breaker is a circuit breaker
in which vacuum is used to extinct the arc.
VCB have excellent interruption and
dielectric recovery characteristics, and can
interrupt the high frequency currents which
result from arc instability, superimposed on
the line frequency current.
Used for Medium voltage (11 kV to 33 kV)
High insulating medium for arc extinction
More efficient, Less Bulky and Cheaper cost

9. Construction of VCB
The moving support is provided between the
insulator and metallic bellow.
A glass vessel or ceramic vessel is used as the
outer insulating body.
The arc shield prevents the deterioration of the
internal dielectric strength by preventing metallic
vapors falling on the inside surface of the outer
insulating cover
The fixed contact is a permanent contact
provided in the VCB between the insulator support
and pole terminal.

10. Working of VCB
•
•
•

11. Block diagram of MVCB
INPUT SUPPLY
OUTPUT
SUPPLY
FIXED CONTACT
MOVINGCONTACT
GEAR
CONTROLLER

12. General Parts of
VCB
 CurrentTransformer (CT)
 NO/NC Switch
 Indicator
 Transformer
 Capacitor
 Relay
 Bridge Rectifier
 Fiber Glass
 Resistor

13. Current
Trasformer
(CT)
 Produces the AC in the Secondary
coil proportional to the AC in the
Primary coil
 Induced secondary coil suitable for
measuring instruments
 Reduction of high-voltage current
and allows safely monitoring the
actual current

14. NO/ NC Switch
NO: NORMALLY OPEN NC: NORMALLY CLOSE

15. Indicat
or
 Complete range of maintainance
free LEDS
 Red, Green, Blue,White and Infra-
red light

16. Transformer
 Transfers energy by inductive
coupling between winding circuits
 Varying inductive current
produces varying magnetic flux in
the secondary current
 Finally induces a varying
electromotive force

17. Capacito
r
Ability to store charge in the form
of eletrical filed
Available in different forms

18. Relay Electrically operated switch
Set of input terminal for single or multiple
signals
Used where it is necessary to control current
by an independent low-power signal
Was first used in long-distance telegraph
circuit

19. Bridge
rectifi
er  AC to DC converters
 Rectifies the inputr AD to output
DC

20. Fiber
Glass
Used for insulation
Final Structure to be strong
Easily detect the fault without
opeing the case

21. Transisto
r
Semi-conducting device
Used for amplifying, controllling and
generating electrical signals
Three parts: Emitter, Collector and Base
Two types: PNP and NPN

22. Resistor
Resists the current

23. Advantages of VCB
Simple construction.
Self-contained i.e., no need of periodic refilling of gas or oil.
 Compact size.
 Low power requirement for making and breaking operations.
Pollution free
Long life
Non-explosive.
 Silent operation.
Low maintenance.
Capable of interrupting highly inductive and capacitive currents without restricting.

24. Disadvantages of MVCB
 Vacuum circuit breaker are uneconomical above 36 KV.
 No remote control.
 The cost of the breaker becomes excessive at higher voltages.
This is due to the fact that at high voltages (above 38 KV)
more than two numbers of the circuit breaker are required to
be connected in series.

25. Application and
Use of VCB
 Useful as very high speed making
switches
 Definite superiority when the voltage
is high and current is low
 Low cost for low fault interrupting
capacities
 Very suitble for the system which
requires voltage from 11 kV to 33 kV.

26. Comparison between VCB over
Traditional circuit breaker
 Replacement of tin container with the glass optical fiber can be the game
changer for the maintenance of the circuit breaker.
 The limit of the circuit breaker over the fixed value is gone. Now, this Modified
vacuum circuit breaker can easily be adjusted from 6A to 1000 A of current
flowing.
 This modified vacuum circuit breaker even beats the MCB which is restricted up
to 100A.
 This ModifiedVCB needs manuallyON the modified vacuum circuit breaker
after each breakup because this system is built up with the capacity to
automatically come into operation once the faulty is resolved.
 The extremely low permeability of vacuum make it good insulation and thus
enhances the working range.
 The use of locally available component has made it cheaper than those available
in the market.
 it is environmentally friendly.

27. Estimation And Costing of VCB

28. Conclusion
Thus, a circuit breaker is equipment that breaks a circuit either
manually or automatically under all conditions at no load, full
load or short circuit.
No fire hazards, no gas generation, low arc generation, little
maintenance
Hence, we can say that Vacuum circuit breaker is really the most
reliable one with low cost, no fire hazards, no gas generation, low
arc energy, little maintenance and low inertia. So this is the most
widely used circuit breaker used for high voltage transmission.
Vacuum circuit breaker is really the most reliable one with low
cost.

29. Thank you