This document provides an overview of circuit breakers, including their operating principles, components, and classifications. Circuit breakers are mechanical switching devices that open and close electrical circuits under normal and abnormal conditions. They contain fixed and moving contacts to carry current when closed. When a fault occurs, the contacts separate, creating an arc that must be extinguished quickly. Circuit breakers use various insulating fluids or methods to cool the arc and reduce its conduction in order to interrupt the current. Common types include oil, air, sulfur hexafluoride, and vacuum circuit breakers.
Every power supply depends upon a reliable infeed of electricity. Air circuit breakers reliably protect electrical installations against damage or fire as a result of short circuits, ground faults, or overload faults.
Every power supply depends upon a reliable infeed of electricity. Air circuit breakers reliably protect electrical installations against damage or fire as a result of short circuits, ground faults, or overload faults.
he apparatus used for switching, controlling and protecting the electrical circuits and equipment is known as switchgear. Switches, fuse, circuit breaker, relay, isolator this are some essential switchgear used in domestic and industrial application.
Circuit BreakersA 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.
Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-w
An electrical circuit breaker is a switching device which can be operated manually and automatically for controlling and protection of electrical power system respectively. As the modern power system deals with huge currents, the special attention should be given during designing of circuit breaker for safe interruption of arc produced during the operation of circuit breaker.
The modern power system deals with huge power network and huge numbers of associated electrical equipments. During short circuit fault or any other types of electrical fault these equipment as well as the power network suffer a high stress of fault current in them which may damage the equipment and networks permanently.
For saving these equipment and the power networks the fault current should be cleared from the system as quickly as possible. Again after the fault is cleared, the system must come to its normal working condition as soon as possible for supplying reliable quality power to the receiving ends. In addition to that for proper controlling of power system, different switching operations are required to be performed.
So for timely disconnecting and reconnecting different parts of power system network for protection and control, there must be some special type of switching devices which can be operated safely under huge current carrying condition. During interruption of huge current, there would be large arcing in between switching contacts, so care should be taken to quench these arcs in circuit breaker in safe manner. The circuit breaker is the special device which does all the required switching operations during current carrying condition.
he apparatus used for switching, controlling and protecting the electrical circuits and equipment is known as switchgear. Switches, fuse, circuit breaker, relay, isolator this are some essential switchgear used in domestic and industrial application.
Circuit BreakersA 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.
Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-writing modes. As stated in Writing from A to Z, edited by Kirk Polking, description is more than the amassing of details; it is bringing something to life by carefully choosing and arranging words and phrases to produce the desired effect (Polking 1990, p. 106). The most appropriate and effective techniques for presenting description are a matter of ongoing discussion among writers and writing coaches.Fiction is a form of narrative, one of the four rhetorical modes of discourse. Fiction-writing also has modes for fiction-writing: action, exposition, description, dialogue, summary, and transition (Morrell 2006, p. 127). Author Peter Selgin refers to methods, including action, dialogue, thoughts, summary, scene, and description (Selgin 2007, p. 38). Currently, there is no consensus within the writing community regarding the number and composition of fiction-writing modes and their uses.
Description is the fiction-writing mode for transmitting a mental image of the particulars of a story. Together with dialogue, narration, exposition, and summarization, description is one of the most widely recognized of the fiction-w
An electrical circuit breaker is a switching device which can be operated manually and automatically for controlling and protection of electrical power system respectively. As the modern power system deals with huge currents, the special attention should be given during designing of circuit breaker for safe interruption of arc produced during the operation of circuit breaker.
The modern power system deals with huge power network and huge numbers of associated electrical equipments. During short circuit fault or any other types of electrical fault these equipment as well as the power network suffer a high stress of fault current in them which may damage the equipment and networks permanently.
For saving these equipment and the power networks the fault current should be cleared from the system as quickly as possible. Again after the fault is cleared, the system must come to its normal working condition as soon as possible for supplying reliable quality power to the receiving ends. In addition to that for proper controlling of power system, different switching operations are required to be performed.
So for timely disconnecting and reconnecting different parts of power system network for protection and control, there must be some special type of switching devices which can be operated safely under huge current carrying condition. During interruption of huge current, there would be large arcing in between switching contacts, so care should be taken to quench these arcs in circuit breaker in safe manner. The circuit breaker is the special device which does all the required switching operations during current carrying condition.
A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit.
Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow.
It describes about the circuit breaker and components and types of high voltage circuit breaker. It also explains about the working principle of the circuit breaker.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
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Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
2. Main point will covered in this presentation
1- General
2- circuit breaker
2.1- General
2.2- Rate terms of circuit breaker
2.3- operating principle
2.4- the insulation fluids commonly used as insulation
medium during the separation of contact
3- Arc phenomena
3.1- General
3.2- initiation of an arc
3.3- Maintenance of arc
3.4- Arc voltage
4- Arc Extinction
4.1- General
4.2- Method of Arc phenomena
4.2.1- High Resistance Method
4.2.2- LOW Resistance Method
3. 5- Classification of circuit breaker
6- Main type of circuit breaker
7- scoop on some types with some details
8-Tesying of circuit breaker
4. 1. General
A switch is used for opening and
closing of an electric circuit. Every
electric circuit needs a switching
device and protective device.
SSwwiittcchhggeeaarr is a general term covering
a wide rang of equipment concerned
with switching and protection.
In a power system switchgear serves two basic purposes:
1. Switching during normal operating condition for purpose
of operation and maintenance.
2. Switching during abnormal condition such as short-circuits
and interrupting the fault current.
5. The first of above could be served by relatively simple
switches because it is relatively simple as it involves
normal current which are easy to interrupt. The second
function is however complex.
With the advancement of electrical power system the lines
and other equipment operate at very high voltage and
carry large current. Whenever a short-circuit occurs, a
heavy current flows through the equipment causing
considerable damage to the equipment and interruption
the service.
In order to avoid such damage every part of the power
system is provided with a protective relaying system and
an associated switching device. The relaying equipment is
aided in this task by circuit breaker.
6. 2. Circuit breaker
2.1 General
Circuit breaker are a mechanical
device designed to close or open the
contact members, thus closing or
opining of an electrical circuit under
normal or abnormal condition.
The automatic circuit breakers perform the following duties:
1. It carries the full-load current continuously without
overheating or damage.
2. It open and close the circuit on no load.
3. It makes and breaks the normal operating current.
4. It makes and breaks the short-circuit current of magnitude
up to which it designed for.
7. 2.2 Rate terms of circuit breaker
• Max voltage
• NO, of poles
• Frequency
• Maximum continuous current
carrying capacity
• Max interrupting capacity
• Max momentary
8. 2.3 Operating principle
A circuit breaker as a switching and
current interrupting consist of fixed and
moving contacts, which are touching
each other and carry the current under
normal condition. When the circuit
breaker is closed, the current carrying
contacts, called the electrodes, engage
each other under the pressure of a
spring.
Whenever a fault occurs on any part
of the power system, the trip coils of the
breaker get energized and the moving
contacts are pulled apart by some
mechanism, thus opening the circuit. The
separation of current carrying production
an arc. The current is thus able to
continue until the discharge ceases.
9. Therefore the main problem in circuit breaker is to
extinguish the arc within the shortest possible time so
that heats generated by it not reach a dangerous
value.
The production of arc not
only delays the current
interruption process but it
also generates enormous
heat which may cause
damage to the system or to
the breaker itself.
10. The basic construction of circuit breaker requires the
separation of the contacts in an insulating fluid which
serve two functions:
1. Extinguishes the arc drawn between the contacts when
the circuit breaker opens.
2. Provides insulation between the contact and from each
contact to earth.
The insulating fluids commonly used for this purpose
are as follows:
1. Air and atmospheric pressure.
2. Compressed air.
3. Oil producing hydrogen for arc extinction.
4. Ultra high vacuum
5. Sulphur hexa-fluoride (SF6)
11. 3. Arc phenomena
The heats generated from the
arc ionize the air molecules. So
the +ve ions attracted to the –ve
contact and the –ve ions
attracted to the +ve contact.
Thus current flow is caused due
to movement of electrons.
3.1 Initiation of an arc
Initiating electrons are thought of
produced by the following two
processes:
1. By high voltage gradient at the
cathode resulting into field emission
2. By increase of temperature resulting
into thermal emission
13. 3.2 maintenance of arc
The ionization is further by:
1. High temperature of the medium around the contacts
caused by high current densities.
2. The field strength or voltage gradient which increases
the kinetic energy of moving electrons and increases
the chances of detaching from neutral molecules.
3. An increase of mean free path-the distance through
which the electron moves freely.
All above three processes (thermal emission – ionization –
and field emission) may start either one after the other or
almost simultaneously and enable the arc to be initiated
and maintained.
14. 3.3 Arc voltage
The voltage that appears across the contact of circuit
breaker is called the arc voltage.
For moderated values of current and voltage the arc
characteristic can be expressed by Ayrton's equation
Ea = A + B/ia
:Where
The constant A and B vary
linearly With the arc length l
A=a+g l
B= b+δ l
Average values of a,g,b,δ
for arcs In air between copper electrodes are as following:
a=30v ,g=10v/cm ,b=10VA ,δ=30VA/cm
16. 4. Arc extinction
The conductance of the arc is proportional to
1. The number of electrons per cubic centimeter
produced by ionization
2. The square of the diameter of the arc
3. Reciprocal of the length
The arc extinction can, therefore, be facilitated by
deionizing the arc path. This may be achieved by cooling
the arc or bodily removing the ionized particles from the
space between the circuit breaker contacts.
17. 4.1 Method of arc extinction
High Resistance Method 4.1.1
In this case the arc is controlled in such a way that its effective
resistance increases with the time so that the current is
reduced to such a value that heat produced by it is not
sufficient to maintain the arc and the current is interrupted or
the arc is extinguished.
The resistance of the arc can be increased by:
1. Cooling of arc
2. Increasing the length of arc
3. Reducing the cross-section of arc
4. Splitting of arc
18.
19. 4.1.2 Low resistance OR Current zero interruption
This method is applicable only
in ac circuit interruption
because there is natural zero
current 100 times in a second
for 50Hz supply system.
In this method the arc resistance is kept low until the current is
zero where the arc extinguishes naturally and is prevented
from restriking after it has gone out at current zero.
This method of arc extinction is employed in all modern
high power ac circuit.
20. 5. Duties of circuit breakers
1. Interruption of small inductive current
2. Switching of unloaded transmission lines and unloaded
cables
3. Switching of capacitor banks
4. Interruption of terminal faults
5. Interruption of short-line faults (kilometric fault)
6. Asynchronous switching
21. 6. Resistance switching
It is a deliberate connection of a
resistance in parallel with the
contact space (or arc).
On occurrence of fault, the contacts
of the circuit breaker open and an
arc is struck . between the contacts
With the shunted by resistance R a part of arc current
is diverted through this resistance. This result in the
decrease of arc current and increase in the rate of
deionization of the arc path.
22. 7. Classification of circuit breaker
1. Oil circuit breakers
2. Water type circuit breaker
3. Air-Break circuit breaker
4. Air blast circuit breaker
5. Sulphur Hexafluoride (SF6 ) circuit breaker
6. Vacuum circuit breaker
23. Oil circuit breakers 7.1
· Bulk oil circuit breaker :
using a large quantity of oil, also
called the dead tank type
because the tank is held at
ground potential
· Low oil circuit breaker: which
operate with a min amount of oil,
also sometimes called the live tank circuit breaker because
the oil tank is insulated from the ground.
24. Advantage:
1. Arc energy is absorbed in decomposing of oil.
2. The gas formed which mainly hydrogen is provided good
cooling properties.
3. The oil has a high dielectric insulating between the
contacts after the arc extinguished.
4. The very good insulation medium allows smaller clearance
between line conductors and earth components
25. Disadvantage
1. Oil is inflammable and may cause fire hazards.
2. There is a risk of formation of explosive mixture with air.
3. Due to decomposition of oil in the arc, the oil becomes
pouted by carbon particles, which reduce its dielectric
strength.
26. Maintenance of oil circuit breaker
1. All current carrying parts be checked and arcing
contacts be attended if necessary.
2. Dielectric strength condition and level of oil should be
checked.
3. Inspect the insulation for possible damage. Clean the
surface and remove deposits of carbon
4. Check closing, tripping and interlock mechanism
5. Check indicating devices and lamps
27. Automatic resisting soled state type (PTC)
A polymer PTC (for positive temperature coefficient) is a special
type of circuit breaker called thermistor ( thermal resistor). PTC
resistor increase resistance as its temperature in increase, PTC’s
are made of conductive polymer , are solid state device , which
means they have no moving parts.
28. Polymer PTC construction and operation
In its normal state the material in the polymer PTC is in the form of
a dense crystal with many carbon particles packet together. The
carbon particles provide conductive pathways for current flow.
This resistance is low. When the material is heated from excessive
current the polymer expands, pulling the carbon chains apart, in
this expanded ” tripped ” state there are few pathways for current.
When current floe exceeds the trip threshold, the device remain in
the “open circuit” state as long as voltage is remain applied to the
circuit. It reset only when the voltage is removed and the polymer
is cools.