Relays sense abnormal voltage and current conditions and send signals to circuit breakers to isolate faulty parts of a power system. Electromagnetic induction relays use eddy currents produced in a disc to generate torque. There are different types of overcurrent and directional relays. Distance relays use impedance, reactance, or mho principles. Transformer and feeder protection uses overcurrent, distance, or pilot wire schemes. Circuit breakers use oil, air, sulfur hexafluoride, or vacuum to extinguish arcs and open faulty circuits. Instrument transformers reduce high voltages and currents to safer, measurable levels for meters and relays.
The document discusses different types of switchgears used in power systems, including their definitions, examples, and working principles. It focuses on circuit breakers, describing four main types - oil circuit breakers, air-blast circuit breakers, SF6 circuit breakers, and vacuum circuit breakers. For each type, it provides details on the arc quenching medium used, construction, working, advantages and disadvantages. Key terms like arc voltage, restriking voltage and recovery voltage related to circuit breakers are also explained.
Switchgear is electrical equipment used to control, protect, and isolate electrical systems. It includes components like fuses, switches, relays, and circuit breakers. There are three main types - low voltage, medium voltage, and high voltage. Circuit breakers use various mediums like air, sulfur hexafluoride gas, or oil to detect faults and quickly interrupt current to isolate issues and protect equipment. SF6 gas is commonly used due to its excellent insulating and arc quenching properties. Air blast circuit breakers use compressed air to extinguish arcs by forcing high velocity air jets onto the arc through nozzles.
A circuit breaker is a device used to protect electrical circuits from damage caused by short circuits or overloads. It functions by automatically opening a circuit when excess current is detected. When a fault occurs, the circuit breaker detects it and uses stored mechanical energy to separate its contacts, interrupting the current. This creates an electric arc that must be contained and extinguished in a controlled way before the contacts can be re-closed to restore power. Common circuit breaker components detect faults, open contacts, extinguish arcs through techniques like lengthening or splitting it, and reclose contacts once faults have cleared.
Switchgear and protection engineering Lecture 03.pptxLoitaFredy
The document discusses circuit breakers and power system protection. It begins with an introduction to circuit breakers, explaining their operating principle and how they interrupt current during faults. It describes the arc phenomenon that occurs when contacts open and various methods to extinguish the arc. It also covers circuit breaker classification, ratings, testing and maintenance. The key types discussed are oil, air-blast and sulfur hexafluoride circuit breakers.
Circuit breakers are switching devices that can make, carry, and break electric currents under both normal and abnormal circuit conditions. They contain fixed and moving contacts that remain closed during normal operation but open automatically during faults to interrupt the fault current. When contacts open under fault conditions, an arc is produced that must be quickly extinguished. Different circuit breakers use various mediums like oil, air, vacuum, or SF6 gas to rapidly quench the arc through cooling and increasing dielectric strength between contacts. Common types of circuit breakers include oil, vacuum, air blast, and SF6 breakers that vary based on voltage level, switching speed, maintenance needs, and arc quenching method.
Air Blast & SF6 Circuit Breaker Design and Construction anuphowlader1
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 interrupt current flow.
Relays sense abnormal voltage and current conditions and send signals to circuit breakers to isolate faulty parts of a power system. Electromagnetic induction relays use eddy currents produced in a disc to generate torque. There are different types of overcurrent and directional relays. Distance relays use impedance, reactance, or mho principles. Transformer and feeder protection uses overcurrent, distance, or pilot wire schemes. Circuit breakers use oil, air, sulfur hexafluoride, or vacuum to extinguish arcs and open faulty circuits. Instrument transformers reduce high voltages and currents to safer, measurable levels for meters and relays.
The document discusses different types of switchgears used in power systems, including their definitions, examples, and working principles. It focuses on circuit breakers, describing four main types - oil circuit breakers, air-blast circuit breakers, SF6 circuit breakers, and vacuum circuit breakers. For each type, it provides details on the arc quenching medium used, construction, working, advantages and disadvantages. Key terms like arc voltage, restriking voltage and recovery voltage related to circuit breakers are also explained.
Switchgear is electrical equipment used to control, protect, and isolate electrical systems. It includes components like fuses, switches, relays, and circuit breakers. There are three main types - low voltage, medium voltage, and high voltage. Circuit breakers use various mediums like air, sulfur hexafluoride gas, or oil to detect faults and quickly interrupt current to isolate issues and protect equipment. SF6 gas is commonly used due to its excellent insulating and arc quenching properties. Air blast circuit breakers use compressed air to extinguish arcs by forcing high velocity air jets onto the arc through nozzles.
A circuit breaker is a device used to protect electrical circuits from damage caused by short circuits or overloads. It functions by automatically opening a circuit when excess current is detected. When a fault occurs, the circuit breaker detects it and uses stored mechanical energy to separate its contacts, interrupting the current. This creates an electric arc that must be contained and extinguished in a controlled way before the contacts can be re-closed to restore power. Common circuit breaker components detect faults, open contacts, extinguish arcs through techniques like lengthening or splitting it, and reclose contacts once faults have cleared.
Switchgear and protection engineering Lecture 03.pptxLoitaFredy
The document discusses circuit breakers and power system protection. It begins with an introduction to circuit breakers, explaining their operating principle and how they interrupt current during faults. It describes the arc phenomenon that occurs when contacts open and various methods to extinguish the arc. It also covers circuit breaker classification, ratings, testing and maintenance. The key types discussed are oil, air-blast and sulfur hexafluoride circuit breakers.
Circuit breakers are switching devices that can make, carry, and break electric currents under both normal and abnormal circuit conditions. They contain fixed and moving contacts that remain closed during normal operation but open automatically during faults to interrupt the fault current. When contacts open under fault conditions, an arc is produced that must be quickly extinguished. Different circuit breakers use various mediums like oil, air, vacuum, or SF6 gas to rapidly quench the arc through cooling and increasing dielectric strength between contacts. Common types of circuit breakers include oil, vacuum, air blast, and SF6 breakers that vary based on voltage level, switching speed, maintenance needs, and arc quenching method.
Air Blast & SF6 Circuit Breaker Design and Construction anuphowlader1
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 interrupt current flow.
The document discusses different types of circuit breakers, their origins, operations, and uses. It begins by introducing circuit breakers and their basic functions of fault detection and current interruption. It then discusses the early development of circuit breakers by Thomas Edison in 1879 and the modern miniature circuit breaker patented in 1924. The remainder of the document describes the operations, components, applications, advantages, and disadvantages of various low voltage, medium voltage, high voltage, magnetic, thermal-magnetic, common trip, disconnecting, sulfur hexafluoride, vacuum, and carbon dioxide circuit breakers.
The document discusses electrical safety devices and their importance. It describes how safety features like insulators and circuit breakers help isolate faulty circuits to prevent fires from short circuits. The key safety devices discussed are fuses, circuit breakers, and earthing. Fuses and circuit breakers help protect against overcurrent while earthing protects against leakage current. The document explains how these devices work to rapidly detect faults and shut off power to protect people and equipment.
Non-destructive testing (NDT) involves analysis techniques used to evaluate materials, components, or systems without damaging them. NDT is used to determine properties like resistivity, dielectric constant, and loss factor of insulating materials. It helps ensure materials maintain their insulating properties during operation. Two common methods for measuring dielectric loss and loss angle of insulating materials are the Schering bridge and transformer ratio arm bridge. The loss angle tan δ indicates the quality of insulation and can determine material life expectancy. Partial discharges within insulating materials are detected using NDT and indicate weaknesses.
Unit-5 discusses electrical installations including components of low voltage switchgear, types of wires and cables, earthing concepts, batteries and their characteristics, energy consumption calculations, and power factor improvement methods. The document covers switchgear classification based on voltage level, components of low voltage switchgear like SFU, MCB, MCCB and ELCB. It also discusses types of wires, cables, fuses and their applications. Earthing types include plate, pipe and rod earthing. Energy consumption is calculated based on wattage and usage hours. Methods to improve power factor are static capacitors, synchronous condensers and phase advancers. Battery types covered are primary and secondary cells, with secondary cells including Ni-Cd,
The document discusses circuit breakers, which automatically interrupt electric current to prevent overloads or short circuits from damaging wiring or equipment. It describes how early circuit breakers were developed by Thomas Edison and others, and how modern miniature circuit breakers work. The document outlines different types of circuit breakers, including low-voltage, magnetic, thermal-magnetic, common trip, medium voltage, high voltage, sulfur hexafluoride, disconnecting, and carbon dioxide circuit breakers. It discusses advantages like protection and reliability and disadvantages like initial cost.
This document discusses various switching and control devices used in electric circuits including switches, circuit breakers, and fuses. It describes different types of switches such as knife switches, disconnecting switches, air-break switches, control switches, and oil switches. It also covers types of circuit breakers such as air, air blast, oil, and magnetic blast circuit breakers. Details are provided on circuit breaker components like contacts, construction, and control. Factors that affect the application and ratings of circuit breakers like interrupting capacity, altitude, and duty cycle are also summarized.
A circuit breaker is a device that breaks an electrical circuit automatically or manually under normal, full load, or short circuit conditions. It contains two contacts that remain closed during normal operation. When a fault occurs, a trip coil is energized separating the contacts. An arc is struck during contact separation, allowing current to continue briefly. Circuit breakers must extinguish the arc quickly. Different types of circuit breakers use various methods and mediums like oil, air, vacuum, or sulfur hexafluoride gas to rapidly extinguish the arc. Circuit breakers are classified and selected based on the voltage level and intended application.
This document discusses different types of circuit breakers and their operating principles. It describes how circuit breakers interrupt current by extinguishing the arc that forms between contacts. Vacuum circuit breakers use vacuum as the arc quenching medium, allowing for quick arc extinction due to rapid condensation. Sulfur hexafluoride circuit breakers use SF6 gas, which absorbs electrons from the arc. Air-blast circuit breakers employ high pressure air to cool and sweep away the arc.
This document discusses various aspects of circuit breakers, including their design and operation. It describes how an arc is maintained between contacts during arcing periods and how factors like ionization, arc length and cross-section affect the arc resistance. It then discusses two main methods of arc extinction - the high resistance method which involves lengthening or cooling the arc, and the low resistance method which causes ionized particles to recombine. The document also covers topics like current chopping in air-blast circuit breakers, interruption of capacitive currents, classifications of circuit breakers, and the operation of different types of circuit breakers including oil, vacuum, SF6, and air blast.
This document discusses power semiconductor devices and related topics over multiple pages. It covers SCR firing circuits, commutation circuits, heat sinks, snubber circuits, fuse selection, and the series and parallel operation of SCRs. It also discusses switching losses that occur in semiconductor devices when they are turned on and off. Key points covered include how SCRs are fired, the purpose of commutation and snubber circuits, heat dissipation methods, fuse types and ratings, and factors that influence power losses in semiconductor switches.
This document provides information about various types of circuit breakers presented by Dr. Rohit Babu of Lendi Institute of Engineering and Technology. It defines and classifies circuit breakers based on voltage level, location, external design, and arc quenching medium used. Specific types discussed include miniature circuit breakers, oil circuit breakers, air blast circuit breakers, SF6 circuit breakers, and vacuum circuit breakers. The document also provides details on the construction, working, advantages, and disadvantages of oil circuit breakers and air circuit breakers. It notes that air circuit breakers use compressed air to extinguish arcs and describes their operation and examples like axial blast and cross blast air circuit breakers.
Vacuum circuit breaker selection of circuit breakersshubham_bharadia
This document discusses vacuum circuit breakers and the selection of circuit breakers. It describes the construction of vacuum circuit breakers including their moving contacts, fixed contacts, and arc shields. It explains the principle of operation where an arc is produced and quickly extinguished in vacuum. It discusses the advantages of vacuum circuit breakers such as being compact, reliable, and having a long life. The document also outlines factors to consider when selecting a circuit breaker such as voltage, frequency, interrupting capacity, and continuous current rating. Finally, it provides a table comparing different circuit breaker types and their applicable voltages and breaking capacities.
The document discusses the 220KV/132KV/33KV Bodhgaya Grid Substation (GSS) in Bihar, India. It contains details about the substation's layout and components. The substation has three sections: a 220KV switchyard, 132KV switchyard, and 33KV switchyard. It uses various types of transformers, circuit breakers, capacitors, and other equipment to step down electricity from 220KV and 132KV to 33KV for distribution. The document provides information on how these components work and their purposes in the substation's power transmission system.
Circuit breakers are used to switch and interrupt load currents and fault currents. They must carry fault currents without failing. Modern high speed circuit breakers have tripping times between 3 to 8 cycles. The total clearing time is the sum of the opening time and arcing time. Circuit breakers are classified by the medium they use - oil, air, vacuum, or SF6. SF6 circuit breakers are widely used for higher voltages as SF6 is an excellent insulating and arc quenching gas. Vacuum circuit breakers can interrupt small currents without overvoltages and have long operational lifetimes. Circuit breakers use various mechanisms like hand, spring, motor, solenoid or pneumatic to quickly open and close contacts
Circuit breakers are used to break electric circuits either manually or automatically during faults. When contacts open under a fault, an arc is produced which must be quickly extinguished. There are two main methods: the high resistance method increases arc resistance over time to reduce current below the level needed to sustain the arc, such as by lengthening, cooling, or splitting the arc. The low resistance or current zero method keeps arc resistance low until current reaches zero, then rapidly deionizes the medium between contacts to prevent the arc from restarting when voltage rises again.
1. The document discusses various types of equipment and accessories used in power transmission systems including transmission lines, conductors, insulators, busbars, isolators, cross-arms, lightning arrestors, circuit breakers, and transformers.
2. It classifies transmission lines based on length and voltage into short, medium, and long lines and describes common types of line supports including wooden poles, steel poles, RCC poles, and lattice steel towers.
3. The document provides details on conductors such as ACSR and AAAC, insulator types including pin, suspension, and strain, and circuit breaker types such as oil, air blast, SF6, and vacuum.
The document summarizes the key aspects of a six-month industrial training on circuit breakers. It describes the components and operating principles of various types of circuit breakers, including oil, air blast, SF6, and vacuum circuit breakers. It explains how circuit breakers are able to detect faults and break circuits manually or automatically to protect electrical networks and connected devices.
The document discusses different types of circuit breakers, their origins, operations, and uses. It begins by introducing circuit breakers and their basic functions of fault detection and current interruption. It then discusses the early development of circuit breakers by Thomas Edison in 1879 and the modern miniature circuit breaker patented in 1924. The remainder of the document describes the operations, components, applications, advantages, and disadvantages of various low voltage, medium voltage, high voltage, magnetic, thermal-magnetic, common trip, disconnecting, sulfur hexafluoride, vacuum, and carbon dioxide circuit breakers.
The document discusses electrical safety devices and their importance. It describes how safety features like insulators and circuit breakers help isolate faulty circuits to prevent fires from short circuits. The key safety devices discussed are fuses, circuit breakers, and earthing. Fuses and circuit breakers help protect against overcurrent while earthing protects against leakage current. The document explains how these devices work to rapidly detect faults and shut off power to protect people and equipment.
Non-destructive testing (NDT) involves analysis techniques used to evaluate materials, components, or systems without damaging them. NDT is used to determine properties like resistivity, dielectric constant, and loss factor of insulating materials. It helps ensure materials maintain their insulating properties during operation. Two common methods for measuring dielectric loss and loss angle of insulating materials are the Schering bridge and transformer ratio arm bridge. The loss angle tan δ indicates the quality of insulation and can determine material life expectancy. Partial discharges within insulating materials are detected using NDT and indicate weaknesses.
Unit-5 discusses electrical installations including components of low voltage switchgear, types of wires and cables, earthing concepts, batteries and their characteristics, energy consumption calculations, and power factor improvement methods. The document covers switchgear classification based on voltage level, components of low voltage switchgear like SFU, MCB, MCCB and ELCB. It also discusses types of wires, cables, fuses and their applications. Earthing types include plate, pipe and rod earthing. Energy consumption is calculated based on wattage and usage hours. Methods to improve power factor are static capacitors, synchronous condensers and phase advancers. Battery types covered are primary and secondary cells, with secondary cells including Ni-Cd,
The document discusses circuit breakers, which automatically interrupt electric current to prevent overloads or short circuits from damaging wiring or equipment. It describes how early circuit breakers were developed by Thomas Edison and others, and how modern miniature circuit breakers work. The document outlines different types of circuit breakers, including low-voltage, magnetic, thermal-magnetic, common trip, medium voltage, high voltage, sulfur hexafluoride, disconnecting, and carbon dioxide circuit breakers. It discusses advantages like protection and reliability and disadvantages like initial cost.
This document discusses various switching and control devices used in electric circuits including switches, circuit breakers, and fuses. It describes different types of switches such as knife switches, disconnecting switches, air-break switches, control switches, and oil switches. It also covers types of circuit breakers such as air, air blast, oil, and magnetic blast circuit breakers. Details are provided on circuit breaker components like contacts, construction, and control. Factors that affect the application and ratings of circuit breakers like interrupting capacity, altitude, and duty cycle are also summarized.
A circuit breaker is a device that breaks an electrical circuit automatically or manually under normal, full load, or short circuit conditions. It contains two contacts that remain closed during normal operation. When a fault occurs, a trip coil is energized separating the contacts. An arc is struck during contact separation, allowing current to continue briefly. Circuit breakers must extinguish the arc quickly. Different types of circuit breakers use various methods and mediums like oil, air, vacuum, or sulfur hexafluoride gas to rapidly extinguish the arc. Circuit breakers are classified and selected based on the voltage level and intended application.
This document discusses different types of circuit breakers and their operating principles. It describes how circuit breakers interrupt current by extinguishing the arc that forms between contacts. Vacuum circuit breakers use vacuum as the arc quenching medium, allowing for quick arc extinction due to rapid condensation. Sulfur hexafluoride circuit breakers use SF6 gas, which absorbs electrons from the arc. Air-blast circuit breakers employ high pressure air to cool and sweep away the arc.
This document discusses various aspects of circuit breakers, including their design and operation. It describes how an arc is maintained between contacts during arcing periods and how factors like ionization, arc length and cross-section affect the arc resistance. It then discusses two main methods of arc extinction - the high resistance method which involves lengthening or cooling the arc, and the low resistance method which causes ionized particles to recombine. The document also covers topics like current chopping in air-blast circuit breakers, interruption of capacitive currents, classifications of circuit breakers, and the operation of different types of circuit breakers including oil, vacuum, SF6, and air blast.
This document discusses power semiconductor devices and related topics over multiple pages. It covers SCR firing circuits, commutation circuits, heat sinks, snubber circuits, fuse selection, and the series and parallel operation of SCRs. It also discusses switching losses that occur in semiconductor devices when they are turned on and off. Key points covered include how SCRs are fired, the purpose of commutation and snubber circuits, heat dissipation methods, fuse types and ratings, and factors that influence power losses in semiconductor switches.
This document provides information about various types of circuit breakers presented by Dr. Rohit Babu of Lendi Institute of Engineering and Technology. It defines and classifies circuit breakers based on voltage level, location, external design, and arc quenching medium used. Specific types discussed include miniature circuit breakers, oil circuit breakers, air blast circuit breakers, SF6 circuit breakers, and vacuum circuit breakers. The document also provides details on the construction, working, advantages, and disadvantages of oil circuit breakers and air circuit breakers. It notes that air circuit breakers use compressed air to extinguish arcs and describes their operation and examples like axial blast and cross blast air circuit breakers.
Vacuum circuit breaker selection of circuit breakersshubham_bharadia
This document discusses vacuum circuit breakers and the selection of circuit breakers. It describes the construction of vacuum circuit breakers including their moving contacts, fixed contacts, and arc shields. It explains the principle of operation where an arc is produced and quickly extinguished in vacuum. It discusses the advantages of vacuum circuit breakers such as being compact, reliable, and having a long life. The document also outlines factors to consider when selecting a circuit breaker such as voltage, frequency, interrupting capacity, and continuous current rating. Finally, it provides a table comparing different circuit breaker types and their applicable voltages and breaking capacities.
The document discusses the 220KV/132KV/33KV Bodhgaya Grid Substation (GSS) in Bihar, India. It contains details about the substation's layout and components. The substation has three sections: a 220KV switchyard, 132KV switchyard, and 33KV switchyard. It uses various types of transformers, circuit breakers, capacitors, and other equipment to step down electricity from 220KV and 132KV to 33KV for distribution. The document provides information on how these components work and their purposes in the substation's power transmission system.
Circuit breakers are used to switch and interrupt load currents and fault currents. They must carry fault currents without failing. Modern high speed circuit breakers have tripping times between 3 to 8 cycles. The total clearing time is the sum of the opening time and arcing time. Circuit breakers are classified by the medium they use - oil, air, vacuum, or SF6. SF6 circuit breakers are widely used for higher voltages as SF6 is an excellent insulating and arc quenching gas. Vacuum circuit breakers can interrupt small currents without overvoltages and have long operational lifetimes. Circuit breakers use various mechanisms like hand, spring, motor, solenoid or pneumatic to quickly open and close contacts
Circuit breakers are used to break electric circuits either manually or automatically during faults. When contacts open under a fault, an arc is produced which must be quickly extinguished. There are two main methods: the high resistance method increases arc resistance over time to reduce current below the level needed to sustain the arc, such as by lengthening, cooling, or splitting the arc. The low resistance or current zero method keeps arc resistance low until current reaches zero, then rapidly deionizes the medium between contacts to prevent the arc from restarting when voltage rises again.
1. The document discusses various types of equipment and accessories used in power transmission systems including transmission lines, conductors, insulators, busbars, isolators, cross-arms, lightning arrestors, circuit breakers, and transformers.
2. It classifies transmission lines based on length and voltage into short, medium, and long lines and describes common types of line supports including wooden poles, steel poles, RCC poles, and lattice steel towers.
3. The document provides details on conductors such as ACSR and AAAC, insulator types including pin, suspension, and strain, and circuit breaker types such as oil, air blast, SF6, and vacuum.
The document summarizes the key aspects of a six-month industrial training on circuit breakers. It describes the components and operating principles of various types of circuit breakers, including oil, air blast, SF6, and vacuum circuit breakers. It explains how circuit breakers are able to detect faults and break circuits manually or automatically to protect electrical networks and connected devices.
Similar to Circuit Breaker arc phenomenon.pdf engineering (20)
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Accident detection system project report.pdfKamal Acharya
The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
This study Examines the Effectiveness of Talent Procurement through the Imple...DharmaBanothu
In the world with high technology and fast
forward mindset recruiters are walking/showing interest
towards E-Recruitment. Present most of the HRs of
many companies are choosing E-Recruitment as the best
choice for recruitment. E-Recruitment is being done
through many online platforms like Linkedin, Naukri,
Instagram , Facebook etc. Now with high technology E-
Recruitment has gone through next level by using
Artificial Intelligence too.
Key Words : Talent Management, Talent Acquisition , E-
Recruitment , Artificial Intelligence Introduction
Effectiveness of Talent Acquisition through E-
Recruitment in this topic we will discuss about 4important
and interlinked topics which are
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
Supermarket Management System Project Report.pdfKamal Acharya
Supermarket management is a stand-alone J2EE using Eclipse Juno program.
This project contains all the necessary required information about maintaining
the supermarket billing system.
The core idea of this project to minimize the paper work and centralize the
data. Here all the communication is taken in secure manner. That is, in this
application the information will be stored in client itself. For further security the
data base is stored in the back-end oracle and so no intruders can access it.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
2. Circuit Breaker
• A circuit breaker is an equipment which is
designed to protect an electric circuits from
damage caused by short circuit or overload.
– Make or break a circuit either manually or by
– Make or break a circuit either manually or by
remote control under normal conditions.
– Break a circuit automatically under fault
conditions
– Make a circuit either manually or by remote
control under fault conditions.
3. Operating Principles
• A circuit breaker essentially consists of fixed and
moving contacts, called electrodes.
• Under normal operating conditions, these contacts
remain closed and will not open automatically until
and unless the system becomes faulty.
and unless the system becomes faulty.
• The contacts can be opened manually or by remote
control whenever desired.
• When fault occurs on any part of the system, the trip
coils of the circuit breaker get energized and the
moving contacts are pulled apart by some mechanism,
thus opening the circuit.
4. Operating Principles cont….
• When the contacts of a circuit breaker are separated
under fault conditions, an arc is struck between them.
The current is thus able to continue until the discharge
ceases.
• The production of arc not only delays the current
• 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
circuit breaker itself.
• The main problem in a circuit breaker is to extinguish
the arc within the shortest possible time so that heat
generated by it may not reach a dangerous value.
5. Circuit Breaker
• In addition to these making and breaking
capabilities, circuit breaker are required to do
so under the following typical conditions:
– Short-circuit interruption
– Short-circuit interruption
– Interruption of small inductive currents
– Capacitor switching
– Interruption of short-line fault
6. Circuit breaker
• According to the operating mechanism of
circuit breaker they can be divided as:
• Solenoid………… up to 132 kV
• Spring Charged …….. up to 765 kV
• Spring Charged …….. up to 765 kV
• Hydraulic ….. up to 245 kV
• Pneumatic ….. used up to 400 kV
7. Circuit breaker
• According to the voltage level of installation
types of circuit breaker are referred as:
– High voltage circuit breaker (> 72 kV)
– Medium voltage circuit breaker (1-72 kV)
– Medium voltage circuit breaker (1-72 kV)
– Low voltage circuit breaker (< 1 kV)
8. Short summary for breakers
• Plain-break air breakers - used in low voltage and
medium voltage up to 15 kV
• For low and medium voltages fuses can be also used,
but the main disadvantage is that they must be
replaced after fault clearing
• In medium voltage systems - minimum oil, SF6 and
• In medium voltage systems - minimum oil, SF6 and
vacuum breakers used
• For high voltages - minimum oil, SF6 and air blast
breakers used
• The maximum voltage per interrupter is 100 kV for air-
blast and SF6 breakers, 170 kV for minimum oil
breakers
9. Circuit Breaker
• According to their arc quenching (rapid
cooling) media the circuit breaker can be
divided as:
– Air circuit breaker
– Air circuit breaker
– Oil circuit breaker
– Vacuum circuit breaker
– SF6 circuit breaker
10. Types of circuit breaker
• Air circuit breakers (ACB) : The circuit breaker
which operates in air at atmospheric pressure.
• Air-blast break: A blast of compressed air is
directed into the arc path to cool the ionized gas
and remove it from the gap between the
and remove it from the gap between the
contacts.
• Oil circuit breakers (OCB):
• Vacuum circuit breakers (VCB):
• Sulfur-hexafluoride (SF6) circuit breakers: Sulfur-
hexafluoride (SF6) is an excellent gaseous
dielectric for high voltage power applications.
15. Circuit breaker
• According to their services the circuit breaker
can be divided as:
– Outdoor circuit breaker
– Indoor circuit breaker
– Indoor circuit breaker
16.
17. Arc Phenomena
• When a short-circuit occurs, a heavy current flows through the
contacts of the circuit breaker before they are opened by the
protective system.
• At the instant when the contacts begin to separate, the contact area
decreases rapidly and large fault current causes increased current
density and hence rise in temperature.
• The heat produced in the medium between contacts is sufficient to
ionize the air or vaporize and ionize the oil.
ionize the air or vaporize and ionize the oil.
• The ionized air or vapour acts as conductor and an arc is struck
between the contacts. The p.d. between the contacts is quite small
and is just sufficient to maintain the arc.
• The arc provides a low resistance path and consequently the
current in the circuit remains uninterrupted so long as the arc
persists.
• During the arcing period, the current flowing between the contacts
depends upon the arc resistance. The greater the arc resistance, the
smaller the current that flows between the contacts.
18. The arc resistance depends upon
• Degree of ionization— the arc resistance increases
with the decrease in the number of ionized particles
between the contacts.
• Length of the arc— the arc resistance increases with
Length of the arc— the arc resistance increases with
the length of the arc i.e., separation of contacts.
• Cross-section of arc— the arc resistance increases
with the decrease in area of X-section of the arc.
19. Factors responsible for maintaining ARC
• P.D. between the contacts
• Ionized particles between contacts
– P.D. between the contacts:
• When the contacts have a small separation, the p.d.
• When the contacts have a small separation, the p.d.
between them is sufficient to maintain the arc.
• One way to extinguish the arc is to separate the contacts to
such a distance that p.d. becomes inadequate to maintain
the arc.
• However, this method is impracticable in high voltage system
where a separation of many meters may be required.
20. Factors responsible for maintaining ARC
– Ionized particles between contacts:
• The ionized particles between the contacts tend to
maintain the arc.
• If the arc path is deionized, the arc extinction will be
facilitated.
facilitated.
• This may be achieved by cooling the arc or by bodily
removing the ionized particles from the space between
the contacts.
21. Methods of arc Extinction
• High resistance method.
• Low resistance method or current zero
method.
22. High resistance method
• In this method, arc resistance is made to
increase with time so that current is reduced
to a value insufficient to maintain the arc.
• Consequently, the current is interrupted or
• Consequently, the current is interrupted or
the arc is extinguished.
• The principle disadvantage of this method is
that enormous energy is dissipated in the arc.
• It is employed only in d.c. circuit breakers and
low-capacity a.c. circuit breakers.
23. Methods of increasing arc resistance
• Lengthening of arc.
• Cooling of arc.
• Reducing cross section area of arc.
• Splitting the arc.
• Splitting the arc.
24. Methods of increasing arc resistance cont…
• Lengthening the arc
– The resistance of the arc is directly proportional to its
length.
– The length of the arc can be increased by increasing the
gap between contacts.
gap between contacts.
• Cooling the arc
– Cooling helps in the deionization of the medium between
the contacts.
– This increases the arc resistance.
– Efficient cooling may be obtained by a gas blast directed
along the arc.
25. Methods of increasing arc resistance
• Reducing X-section of the arc
– If the area of X-section of the arc is reduced, the voltage
necessary to maintain the arc is increased.
– The cross-section of the arc can be reduced by letting
the arc pass through a narrow opening or by having
smaller area of contacts.
smaller area of contacts.
• Splitting the arc
– The resistance of the arc can be increased by splitting
the arc into a number of smaller arcs in series.
– Each one of these arcs experiences the effect of
lengthening and cooling.
– The arc may be split by introducing some conducting
plates between the contacts.
26. Low Resistance or Current Zero Method
• Low resistance method is applicable only for ac circuit and it is
possible there because of presence of natural zero of current.
• In an a.c. system, current drops to zero after every half-cycle. At
every current zero, the arc extinguishes for a brief moment.
• The medium between the contacts contains ions and
electrons so that it has small dielectric strength and can be
electrons so that it has small dielectric strength and can be
easily broken down by the rising contact voltage known as
restriking voltage.
• If such a breakdown does occur, the arc will persist for another
half cycle. If immediately after current zero, the dielectric
strength of the medium between contacts is built up more
rapidly than the voltage across the contacts, the arc fails to
restrike and the current will be interrupted.
27. Theories of arc extinction phenomenon
Energy Balance Theory
• When the contact of circuit breaker are about to open,
restriking voltage is zero, hence generated heat would be
zero and when the contacts are fully opened there is
infinite resistance this again make no production of heat.
• This means the maximum generated heat is lying
• This means the maximum generated heat is lying
between these two cases.
• This theory is based on the fact that the rate of
generation of heat between the contacts of circuit
breaker is lower than the rate at which heat between the
contact is dissipated.
• Thus if it is possible to remove the generated heat by
cooling, lengthening and splitting the arc at a high rate
than the generation, arc can be extinguished.
28. Voltage Race Theory
• The arc is due to the ionization of the gap between the
contact of the circuit breaker.
• Thus the resistance is very small at the initial stage i.e.
when the contacts are closed
• The resistance starts increasing as the contacts get
Theories of arc extinction phenomenon
• The resistance starts increasing as the contacts get
separated.
• If we remove ions at the initial stage either by
recombining them into neutral molecules or inserting
insulation at a rate faster than the rate of ionization, the
arc can be interrupted.
• The ionization at zero current depends on the voltages
known as restriking voltage.
29. Low Resistance or Current Zero Method
• The rapid increase of dielectric strength
of the medium near current zero can be
achieved by :
– Causing the ionized particles in the space between
– Causing the ionized particles in the space between
contacts to recombine into neutral molecules.
– Sweeping the ionized particles away and replacing
them by un-ionized particles
30. Deionization
The Deionization of the medium can be
achieved by following methods:
– Lengthening of the gap.
– High pressure.
– High pressure.
– Cooling.
– Blast effect.
31. Cont….
• Lengthening of the gap
– The dielectric strength of the medium is proportional to
the length of the gap between contacts.
– Therefore, by opening the contacts rapidly, higher
dielectric strength of the medium can be achieved.
• High pressure
• High pressure
– If the pressure in the vicinity of the arc is increased, the
density of the particles constituting the discharge also
increases.
– The increased density of particles causes higher rate of de-
ionization and consequently the dielectric strength of the
medium between contacts is increased.
32. Cont…
• Cooling
– Natural combination of ionized particles takes place
more rapidly if they are allowed to cool.
– Therefore, dielectric strength of the medium between
the contacts can be increased by cooling the arc.
the contacts can be increased by cooling the arc.
• Blast effect
– If the ionized particles between the contacts are
swept away and replaced by unionized particles, the
dielectric strength of the medium can be increased
considerably.
– This may be achieved by a gas blast directed along the
discharge or by forcing oil into the contact space.
33. Arc Voltage, Restriking Voltage and Recovery Voltage
• The basic principle for breaker operation is
to extinguish arc which take place during opening
of circuit breaker. But it does not mean that
arcing do not take place when the breaker is
closed, rather it does.
closed, rather it does.
• The time duration for which arcing take place
when breaker is closed is known as Pre-arcing
Time which is typically around 2 ms and the
duration for which arcing persists when we open
the breaker is known as Arcing Period whose
value is around 6ms.
34. Arc Voltage
• As soon as the Breaker contacts open, an arc is formed
between the contacts of the Circuit Breaker.
• The voltage which appears across the contacts of the
Breaker during this arcing period is called the Arc
Voltage. Its value is low but when the value of arc
Voltage. Its value is low but when the value of arc
current reaches to zero, arc voltage will shoot up to its
peak value which in turn will try to maintain the arc
across the contacts.
• So here we come to a voltage which shoots up to peak
when the current crosses to its zero. Actually this is the
origination of Restriking Voltage.
35. Restriking voltage
• As the arcing current crosses zero, a high
frequency transient voltage appears across the
contacts of the Circuit Breaker. This Transient
voltage is known as Restriking Voltage.
• The power system has appreciable amount of
• The power system has appreciable amount of
inductance, thus the fault current must lag
behind the system voltage by 90°.
• Therefore, when the arcing current crosses zero,
the voltage across the contacts of Circuit Breaker
shoots up to its peak value.
36. Restriking voltage
• As the voltage reaches its peak, it restrike the arc and try to
maintain the arc. Due to this the arcing current will increase from
its zero and correspondingly the voltage must also decrease. The
combined effect of increasing current and decreasing voltage across
the contact will bring the voltage back to its normal value within
few mili seconds.
• Restriking Voltage has a very important role in the arc extinction
process. If the Restriking Voltage rises more rapidly than the
process. If the Restriking Voltage rises more rapidly than the
dielectric strength of the medium between the contacts of the
Circuit Breaker, the arc will persists for next half cycle and after next
half cycle, arcing current will again reach to its zero and we will
again get a chance. If this time the rate of rise of dielectric strength
of medium between the contacts is more than rate of rise of
Restriking Voltage then arc will extinguish.
• Therefore, for arc extinction the rate of Rise of Restriking Voltage
should be less than the rate of Rise of Dielectric Strength of
Medium
38. • Let us consider a simple circuit, having a circuit breaker CB, as illustrated in
Fig. and that a short circuit occurs on the feeder close to the bus-bars. Let
L be the inductance per phase of the system up to the fault point, R be the
resistance per phase of the system up to the fault point and C be the
capacitance per phase to earth of the system.
• Consider the opening of a circuit breaker under fault conditions. Before
current interruption, the capacitance C is short circuited by the fault and
the short-circuit current through the breaker is limited by resistance R and
inductance L of the system. If R is negligible compared to L, the short-
Restriking voltage
inductance L of the system. If R is negligible compared to L, the short-
circuit current i will lag behind the system voltage v by 90°.
• With the contacts opened and the arc broken, current i is diverted through
capacitance C so that the voltage v, which has so far been effective only
across the inductance L, is suddenly applied to the inductance L and
capacitance C in series which form an oscillatory circuit, having a natural
frequency.
fn = 1 / (2ᴨ √(LC))
• The initial charging current surge tends to carry the voltage across the
capacitor, and therefore across the circuit breaker contacts to double its
equilibrium value i.e., 2 Vmax; this is the re-striking voltage transient which
tends to re-establish the arc in the circuit breaker.
39. Recovery Voltage
• It is the normal frequency (50 Hz) r.m.s. voltage that appears across
the contacts of the circuit breaker after final arc extinction.
• When contacts of circuit breaker are opened, current drops to zero
after every half cycle.
• At some current zero, the contacts are separated sufficiently apart
and dielectric strength of the medium between the contacts attains
a high value due to the removal of ionized particles.
a high value due to the removal of ionized particles.
• At such an instant, the medium between the contacts is strong
enough to prevent the breakdown by the restriking voltage.
• Consequently, the final arc extinction takes place and circuit current
is interrupted. Immediately after final current interruption, the
voltage that appears across the contacts has a transient part.
• The voltage across the contacts is of normal frequency is known as
recovery voltage.
40. Some basic formulae
• Rate of rise of restriking voltage = RRRV
• Recovery voltage V = Isc * X
– Isc = Short circuit current; X = Reactance
• Peak value of recovery voltage Vmax = √2 * V
• Max value of restriking voltage = 2Vmax
Time to reach the first peak restriking voltage, t = ᴨ √(LC)
• Time to reach the first peak restriking voltage, t = ᴨ √(LC)
• Time to attain max RRRV, t = ᴨ √(LC) /2
• Natural frequency of the circuit, fn = 1 / (2ᴨ √(LC))
• Average rate of rise of restriking voltage,
•
RRRVav = 2Vmax /(ᴨ √(LC))
• Maximum value of RRRV
RRRVmax = Vmax /√(LC)
41. Examples
• A 50 Hz, 11 kV generator is connected to a power system. The system
inductance and capacitance per phase are 10 mH and 0.02 µF respectively.
Calculate;
– a. max voltage across the contacts of the CB at an instant when it passes
through zero.
– b. frequency of transient oscillation
– c. avg rate of rise of voltage up to the first peak of oscillation, neglect
resistance.
• Solution:
a) Active recovery voltage Vmax = √2 * Vph = √2 * 11/ √3 = 8.98 kV
Max Restriking voltage = 2 * Vmax = 2*8.98 = 17.96 kV
b) fn = 1 / (2ᴨ √LC) = 1 / (2ᴨ √10x10-3 x 0.02x10-6) = 11.254 kHz
c) Av RRRV = 2Vmax /(ᴨ √LC)
= 2*8.98/(ᴨ √10x10-3 x 0.02x10-6)
= 0.404 kV/µs
42. Examples
• In a short circuit test on a circuit breaker, the following
data was obtained on a frequency transient.
(i) Time to reach the peak restriking voltage 55 µs.
(ii) The peak restriking voltage 100 kV.
Determine;
a) Natural frequency of the circuit
a) Natural frequency of the circuit
b) Avg rate of rise of restriking voltage
• Solution:
a) t = ᴨ √(LC) = 55 µs.
fn = 1 / (2ᴨ √(LC)) = 1 / (2*55*10-6) = 9091 Hz
b) Av RRRV = 2Vmax /(ᴨ √(LC)) = 100/55 = 1.82 kV/ µs
43. Examples
• In a system of 132 kV, the circuit phase to ground
capacitance is 0.02 µF and the circuit inductance is 5 H.
The circuit breaker interrupts a magnetizing current of
5 A (peak). Find;
– a) The voltage across the CB contacts after the
circuit interruption
– a) The voltage across the CB contacts after the
circuit interruption
– b) The value of resistance to be used across the
contacts to suppress restriking voltage
• Solution:
a) v = i √ (L/C) = 5* √ (5/0.02x10-6) = 79 kV
b) R = 0.5 √ (L/C) = 0.5 * √ (5/0.02x10-6) = 7.9 kΩ