Generation of High D.C. Voltage (HVDC generation)RP6997
Generation of high dc voltage using different methods like half wave and full wave rectifier, voltage doubler circuits, voltage multiplier circuits, cockcroft-walton circuits and van de graaff generators.
After going through this presentation one can understand the effects undergoing on Transmission Line
Following are some effects...
1. Skin effect
2. Proximity effect
3. Ferranti effect
Generation of High D.C. Voltage (HVDC generation)RP6997
Generation of high dc voltage using different methods like half wave and full wave rectifier, voltage doubler circuits, voltage multiplier circuits, cockcroft-walton circuits and van de graaff generators.
After going through this presentation one can understand the effects undergoing on Transmission Line
Following are some effects...
1. Skin effect
2. Proximity effect
3. Ferranti effect
Townsend ’s theory
Introduction
Ionization by collision
Townsend’s current growth equation
Current Growth in the Presence of Secondary Processes
Townsend’s secondary ionization coefficient
Townsend’s Criterion for Breakdown
Breakdown in Electronegative Gases
HVDC (high-voltage direct current) is a highly efficient alternative for transmitting large amounts of electricity over long distances and for special purpose applications.
As we have discussed that out of various triggering methods to turn the SCR, gate triggering is the most efficient and reliable method. Most of the control applications use this type of triggering because the desired instant of SCR turning is possible with gate triggering method.
Distribution System Voltage Drop and Power Loss CalculationAmeen San
Distribution System Voltage Drop and Power Loss
Calculation
Comparison of Overhead Versus Underground System
Power Loss Calculation,Voltage Drop Calculation
Townsend ’s theory
Introduction
Ionization by collision
Townsend’s current growth equation
Current Growth in the Presence of Secondary Processes
Townsend’s secondary ionization coefficient
Townsend’s Criterion for Breakdown
Breakdown in Electronegative Gases
HVDC (high-voltage direct current) is a highly efficient alternative for transmitting large amounts of electricity over long distances and for special purpose applications.
As we have discussed that out of various triggering methods to turn the SCR, gate triggering is the most efficient and reliable method. Most of the control applications use this type of triggering because the desired instant of SCR turning is possible with gate triggering method.
Distribution System Voltage Drop and Power Loss CalculationAmeen San
Distribution System Voltage Drop and Power Loss
Calculation
Comparison of Overhead Versus Underground System
Power Loss Calculation,Voltage Drop Calculation
Disadvantages of corona, radio interference, inductive interference between p...vishalgohel12195
Disadvantages of corona, radio interference, inductive interference between power and communication lines
Introduction
Disadvantages of corona.
Radio interference.
Inductive interference between power and communication lines
The Presentation represents one of the electromagnatic effect on transmission line (The skin effect), other being the proximity effect.
The Following topics are covered :
1.Defination
2,Cause
3.Formula
4.Skin Depth
5.Mitigation Techniques.
This fun and visually appealing presentation about the core concept of diodes formation and application is thoroughly researched and concise. It contains fun tit-bits of info that make the concept of depletion layer easy to understand. It has a vibrant color scheme to make a perfect first impression for any project...
Bundle conductors in transmission line chandan kumar
Bundled Conductors are used in transmission lines where the voltage exceeds 230 kV.
At such high voltages, ordinary conductors will result in excessive corona and noise which may affect communication lines.
The increased corona will result in significant power loss. Bundle conductors consist of three or four conductors for each phase.
The conductors are separated from each other by means of spacers at regular intervals. Thus, they do not touch each other.
Similar to Skin effect, proximity effect, ferranti effect, corona discharge (20)
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.
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.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
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Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
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
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Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
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2. SKIN EFFECT
• The non-uniform distribution of electric current over the surface or
skin of the conductor carrying a.c. is called the skin effect.
• The concentration of charge is more near the surface as compared to
the core of the conductor.
• The effective resistance of the conductor is increased due to the
concentration of current on the surface of the conductor.
• Skin effect increases with the increase in frequency. At low frequency,
such as 50Hz, there is a small increase in the current density near the
surface of the conductor. At high frequencies, such as radio
frequency, practically the whole of the currents flows on the surface
of the conductor.
• If d.c. current (frequency=0) is passed in a conductor, the current is
uniformly distributed over the cross-section of the conductors.
3.
4. Why skin effect occurs?
• Let us consider the conductor is made up of a number of concentric
cylinders. When a.c is passed in a conductor, the magnetic flux induces in
it. The magnetic flux linking a cylindrical element near the center is greater
than that linking another cylindrical element near the surface of the
conductor. This is due to the fact that the center cylindrical element is
surrounded by both the internal as well as the external flux, while the
external cylindrical element is surrounded by the external flux only.
• The self-inductance in the inner cylindrical element is more and, therefore,
will offer a greater inductive reactance than the outer cylindrical element.
This difference in the inductive reactance gives a tendency to the current to
concentrate towards the surface or skin of the conductor.
• The current density is maximum at the surface of the conductor and
minimum at the center of the conductor. The effect is equivalent to a
reduction of the cross-section area of the conductor and, therefore the
effective resistance of the conductor is increased.
5. Factors affecting Skin effect
• Frequency – Skin effect increases with the increase in frequency.
• Diameter – It increases with the increase in diameter of the
conductor.
• The shape of the conductor – Skin effect is more in the solid
conductor and less in the stranded conductor because the surface
area of the solid conductor is more.
• Type of material – Skin effect increase with the increase in the
permeability of the material (Permeability is the ability of material to
support the formation of the magnetic field).
6. Proximity Effect
The term proximity effect refers to the influence of alternating current
in conductor on the current distribution in another, nearby conductor.
When two or more conductors are placed near to each other, then
their electromagnetic fields interact with each other. Due to this
interaction, the current in each of them is redistributed.
If the conductors carry the current in the same direction, then the
magnetic field of the halves of the conductors which are close to each
other is cancelling each other and hence no current flow through that
halves portion of the conductor. The current is crowded in the remote
half portion of the conductor.
7. When the conductors carry the current in the opposite direction, then
the close part of the conductor carries, the more current and the
magnetic field of the far off half of the conductor cancel each other.
Thus, the current is zero in the remote half of the conductor and
crowded at the nearer part of the conductor
8. If DC flows on the surface of the conductor, then the current are
uniformly distributed around the cross section area of the conductor.
Hence, no proximity effect occurs on the surface of the conductor.
9. Factors affecting Proximity Effect?
• This effect increases with increase in frequency.
• More the diameter of conductor, the more will be this effect.
• This effect also depends on the material of conductor.
• Proximity effect is more in case of solid conductor. This is the reason,
stranded or ACSR conductors are used to reduce this effect.
10. Ferranti Effect
• The Ferranti effect is a phenomenon that describes the increase in
voltage at the receiving end of a long transmission line relative to the
voltage at the sending end when the lines are either lightly loaded or
open circuit.
• Ferranti effect is due to the charging current of the line. When an
alternating voltage is applied, the current that flows into the capacitor
is called charging current. A charging current is also known as
capacitive current.
11. Why Ferranti effect occurs?
• The capacitance (and charging current) is negligible in short line but
significant in medium line and appreciable in long line. Therefore this
phenomenon occurs in medium and long lines.
• The capacitor charging current leads to a voltage drop across the line
inductor of the transmission system which is in phase with the
sending end voltages. This voltage drop keeps on increasing additively
as we move towards the load end of the line and subsequently, the
receiving end voltage tends to get larger than applied voltage.
12. How to reduce Ferranti effect
Electrical devices are designed to work at some particular voltage. If
the voltages are high at the user ends their equipment get damaged,
and their windings burn because of high voltage. Ferranti effect on long
transmission lines at low load or no load increases the receiving end
voltage. This voltage can be controlled by placing the shunt reactors at
the receiving end of the lines.
Shunt reactor is an inductive current element connected between line
and neutral to compensate the capacitive current from transmission
lines. When this effect occurs in long transmission lines, shunt reactors
compensate the capacitive VAr of the lines and therefore the voltage is
regulated within the prescribed limits.
13. Corona Discharge
The phenomenon of violet glow, hissing noise and production of ozone gas in an
overhead transmission line is called as corona.
Corona Discharge (also known as the Corona Effect) is an electrical discharge
caused by the ionization of a fluid such as air surrounding a conductor that is
electrically charged. The corona effect will occur in high voltage systems unless
sufficient care is taken to limit the strength of the surrounding electric field.
Corona discharge can cause an audible hissing or cracking noise as it ionizes the air
around the conductors. This is common in high voltage electric power transmission
lines. The corona effect can also produce a violet glow, production of ozone gas
around the conductor, radio interference, and electrical power loss.
The corona effect occurs naturally due to the fact that air is not a perfect insulator –
containing many free electrons and ions under normal conditions. When an electric
field is established in the air between two conductors, the free ions and electrons
in the air will experience a force. Due to this effect, the ions and free electrons get
accelerated and moved in the opposite direction.
14. The charged particles during their motion collide with one another and
also with slow-moving uncharged molecules. Thus the number of
charged particles increases rapidly. If the electric field is strong enough,
a dielectric breakdown of air will occur and an arc will form between
the conductors.
Minimizing these energy losses has been a major challenge for power
engineers. Corona discharge can significantly reduce the efficiency of
EHV (Extra High Voltage) lines in power systems.
Two factors are important for corona discharge to occur:
1. Alternating electrical potential difference must be supplied across
the line.
2. The spacing of the conductors, must be large enough compared to
the line diameter.
15. Factors Affecting Corona Loss
The main factors affecting corona discharge are:
• Atmosphere
• Conductor size
• Spacing between conductors
• Line voltage
16. Advantages
• Virtual increase in conductor diameter.
• Effects of transients produced by lighting and other causes are
reduced.
17. Disadvantages
• Loss of power.
• There is non sinusoidal voltage drop due to non sinusoidal corona
current.
• Corrosion on the conductor due to chemical action takes place.
18. Critical Disruptive Voltage
The voltage at which corona is just initiated is called critical disruptive
voltage.
At Critical disruptive voltage corona is not visible but noise can be
heard.
Critical visual voltage
The voltage at which corona is visible with violet colour is called
critical visual voltage.
19. Q-1. Find the critical disruptive voltage and the critical voltages for local and general corona on a 3
phase overhead transmission line, consisting of three stranded copper conductors spaced 2.5 m
apart at the corners of an equilateral triangle. Air temperature and pressure are 21°C and 73.6 cm
Hg respectively. The conductor dia, irregularity factor and surface factors are 10.4 mm, 0.85, 0.7 and
0.8 respectively.