The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
In the past few years we have experienced big disturbances in
the power system which caused complete blackout and million
of users including industry have suffered big economical
losses. These disturbances cause big oscillations in active and
reactive power, low voltage, voltage instability and phase or
angular instability between the generated and consumed power
which results in loss of generation and load which effected both
the power generation and the end customers.
During the steady state condition, power systems operate on
the nominal frequency (50Hz or 60Hz). The complete synchronism
of nominal frequency and voltage at the sending and
receiving ends cause complete balance of active and reactive
power between generated and consumed active and reactive
powers. In steady state operating condition Frequency=
Nominal frequency (50 or 60 Hz) +/– 0.02 Hz and
Voltage=Nominal voltage +/– 5% [1].
Power system faults, line switching, generator disconnection,
and the loss or application of large blocks of load result in
sudden changes to electrical power, which is due to the causes
shown
Need for protection
Nature and causes of faults
Types of faults
Fault current calculation using symmetrical components
Zones of protection
Primary and back up protection
Essential qualities of protection
Typical protection schemes.
Main equipment in the power plant is Generator. It's cost is much higher than any other equipment so we will have to protect the generator from all the possible faults and errors.
In the past few years we have experienced big disturbances in
the power system which caused complete blackout and million
of users including industry have suffered big economical
losses. These disturbances cause big oscillations in active and
reactive power, low voltage, voltage instability and phase or
angular instability between the generated and consumed power
which results in loss of generation and load which effected both
the power generation and the end customers.
During the steady state condition, power systems operate on
the nominal frequency (50Hz or 60Hz). The complete synchronism
of nominal frequency and voltage at the sending and
receiving ends cause complete balance of active and reactive
power between generated and consumed active and reactive
powers. In steady state operating condition Frequency=
Nominal frequency (50 or 60 Hz) +/– 0.02 Hz and
Voltage=Nominal voltage +/– 5% [1].
Power system faults, line switching, generator disconnection,
and the loss or application of large blocks of load result in
sudden changes to electrical power, which is due to the causes
shown
Need for protection
Nature and causes of faults
Types of faults
Fault current calculation using symmetrical components
Zones of protection
Primary and back up protection
Essential qualities of protection
Typical protection schemes.
Main equipment in the power plant is Generator. It's cost is much higher than any other equipment so we will have to protect the generator from all the possible faults and errors.
Protection of lines
Overcurrent Protection schemes
PSM, TMS
Numerical examples
Carrier current and three-zone distance relay using impedance relays
Protection of bus bars by using Differential protection
To sense/detect the fault occurrence and other abnormal conditions at the protected equipment/area/section.
To operate the correct circuit breakers so as to disconnect only the faulty equipment/area/section as quickly as possible, thus minimizing the damage caused by the faults.
To operate the correct circuit breakers to isolate the faulty equipment/area/section from the healthy system in the case of abnormalities like overloads, unbalance, undervoltage, etc.
To clear the fault before the system becomes unstable.
To identify distinctly where the fault has occurred.
Differential Protection of Power Transformer in Substationijtsrd
Protection scheme required for the protection of power system components against abnormal conditions such as faults etc., and that essentially consists of protective relaying and circuit breaker. Protective relay senses the fault and determines the location of fault. Then, protective relay sends the tripping command to the circuit breaker. Therefore, proper care should be taken in designing and selecting an appropriate relay which is reliable, efficient and fast in operation. The voltage transformer and current transformer continuously measure the voltage and current of an electrical system and are responsible to give feedback signals to the relays to enable then to detect abnormal conditions. This paper describes differential protection for power transformer, especially the rating of purposed system is 100 MVA, 230 kV 33 kV at substation. Thida Win | Hnin Nandar Maung | Ye Min Hein "Differential Protection of Power Transformer in Substation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27995.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27995/differential-protection-of-power-transformer-in-substation/thida-win
It is based on current transformer description
It's working and applications are present in it ,it also includes videos of it's windings and it's inrush ability of transformer, and also about instrument transformer and it's working with applications.Current transformers are used-in measuring high currents and connected with it in parallel to it
Design of a generating substation with the description of designing a transformer. Here we show some basic components of a substation. and we also show the parameters and calculation to design a transformer of a specific ratings.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
Characteristics Analysis of Voltage Sag in Distribution System using RMS Volt...IDES Editor
Voltage sags caused by the short-circuit faults in
transmission and distribution lines have become one of the
most important power quality problems facing industrial
customers and utilities. Voltage sags are normally described
by characteristics of both magnitude and duration, but phaseangle
jump should be taken into account in identifying sag
phenomena and finding their solutions. In this paper, voltage
sags due to power system faults such as three-phase-to-ground,
single phase-to-ground, phase-to-phase, and two-phase-toground
faults are characterized by using symmetrical
component analysis and their effect on the magnitude
variation and phase-angle jumps for each phase are examined.
A simple and practical method is proposed for voltage sag
detection, by calculating RMS voltage over a window of one
cycle and one-half cycle. The industrial distribution system
at Bajaj hospital is taken as a case study. Simulation studies
have been performed by suing MATLAB/SIMULINK and the
results are presented at various magnitudes, duration and
phase-angle jumps.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Protection of lines
Overcurrent Protection schemes
PSM, TMS
Numerical examples
Carrier current and three-zone distance relay using impedance relays
Protection of bus bars by using Differential protection
To sense/detect the fault occurrence and other abnormal conditions at the protected equipment/area/section.
To operate the correct circuit breakers so as to disconnect only the faulty equipment/area/section as quickly as possible, thus minimizing the damage caused by the faults.
To operate the correct circuit breakers to isolate the faulty equipment/area/section from the healthy system in the case of abnormalities like overloads, unbalance, undervoltage, etc.
To clear the fault before the system becomes unstable.
To identify distinctly where the fault has occurred.
Differential Protection of Power Transformer in Substationijtsrd
Protection scheme required for the protection of power system components against abnormal conditions such as faults etc., and that essentially consists of protective relaying and circuit breaker. Protective relay senses the fault and determines the location of fault. Then, protective relay sends the tripping command to the circuit breaker. Therefore, proper care should be taken in designing and selecting an appropriate relay which is reliable, efficient and fast in operation. The voltage transformer and current transformer continuously measure the voltage and current of an electrical system and are responsible to give feedback signals to the relays to enable then to detect abnormal conditions. This paper describes differential protection for power transformer, especially the rating of purposed system is 100 MVA, 230 kV 33 kV at substation. Thida Win | Hnin Nandar Maung | Ye Min Hein "Differential Protection of Power Transformer in Substation" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd27995.pdfPaper URL: https://www.ijtsrd.com/engineering/electrical-engineering/27995/differential-protection-of-power-transformer-in-substation/thida-win
It is based on current transformer description
It's working and applications are present in it ,it also includes videos of it's windings and it's inrush ability of transformer, and also about instrument transformer and it's working with applications.Current transformers are used-in measuring high currents and connected with it in parallel to it
Design of a generating substation with the description of designing a transformer. Here we show some basic components of a substation. and we also show the parameters and calculation to design a transformer of a specific ratings.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
Characteristics Analysis of Voltage Sag in Distribution System using RMS Volt...IDES Editor
Voltage sags caused by the short-circuit faults in
transmission and distribution lines have become one of the
most important power quality problems facing industrial
customers and utilities. Voltage sags are normally described
by characteristics of both magnitude and duration, but phaseangle
jump should be taken into account in identifying sag
phenomena and finding their solutions. In this paper, voltage
sags due to power system faults such as three-phase-to-ground,
single phase-to-ground, phase-to-phase, and two-phase-toground
faults are characterized by using symmetrical
component analysis and their effect on the magnitude
variation and phase-angle jumps for each phase are examined.
A simple and practical method is proposed for voltage sag
detection, by calculating RMS voltage over a window of one
cycle and one-half cycle. The industrial distribution system
at Bajaj hospital is taken as a case study. Simulation studies
have been performed by suing MATLAB/SIMULINK and the
results are presented at various magnitudes, duration and
phase-angle jumps.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
The use of distributed generation (DG) within distribution systems has increased for the last two decades due to worldwide increase in demand for electricity and governmental policy change from “conventional” energy to “green” energy. High levels of penetration of DG have many significant benefits but also come with many drawbacks such as voltage drop and power losses. This study presents the impact of DG at different locations in a distribution feeder in terms of the feeder voltage profile. A radial distribution system is simulated using PSCAD/EMTDC simulation software while changing the size and location of DG in the system. The obtained results are used for better understanding on the impact of DG on voltage profile in radial distribution feeder.
Impact of Thyristor Controlled Series Capacitor Insertion on Short-circuit Ca...IJAPEJOURNAL
This research paper presents a study on phase to earth fault short-circuit calculation with fault resistance on a single transmission line 400 kV in eastern Algerian transmission networks at Algerian Company of Electricity and Gas (Sonelgaz Group) compensated by series Flexible AC Transmission System (FACTS) i.e. Thyristor Controlled Series Capacitor (TCSC) installed in midline. The facts are used for controlling transmission voltage, power flow, reactive power, and damping of power system oscillations at high power transfer levels. The direct impacts of TCSC insertion on the total impedance, active power and reactive power a electrical transmission line and also parameters of short-circuit : symmetrical currents, line currents, symmetrical voltages and line voltages are carried out. More the effects of injected voltage by TCSC for three case studies are presented.
The traction inverter is a crucial power device in the electric vehicle’s powertrain, and its failure is intolerable as it would considerably compromise the system’s safety. For more reliable driving, installing a traction inverter that is sufficiently resistant to electrical failure is inherent. Due to its compact size and the small number of switches incorporated in three-phase four-switch inverter, this modular topology was used to compensate for the open switch’s failure. However, it is known to have manifold weaknesses mainly distinguished in the low-frequency region. This paper introduces a new fault-tolerant indirect control that handles the IGBT’s failure constituting the traction inverter. The fault compensator is designed first based on the Proportional Integral regulator combined with the notch filter to mitigate the current imbalance and restore the DC voltage equilibrium.Furthermore, to conceive a comprehensive fault-tolerant control, there must therefore contain an accurate fault detector. In this regard, an uncomplicated fault diagnosis method based on the current spectral analysis has been performed. The effectiveness of the submitted controller was validated by simulation using Matlab.
Power Quality Enhancement in an Isolated Power System Using Series CompensationIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Dynamic Performance of Distance Relayson Series Compensated Transmission Line...Premier Publishers
Series compensation is installed in power system networks to increase power transfer capacity, improve the system stability, reduce system losses, improve voltage regulation and for achieving flexible power flow control. Distance relays are widely used as main or backup protection of transmission lines including series-compensated transmission lines. The performance of conventional distance relays is affected by series capacitors and cause certain protection issues. This paper briefly discusses the problems like voltage inversion, current inversion, overreach and under reach during the fault conditions specific to series compensated lines. The behavior of capacitor protection techniques is discussed with simulations performed using Real Time Digital Simulator (RTDS) simulator for a typical 400 kV system having series compensation. The analysis is based on Transmission Line fault simulations, internal and external to the 400-transmission line where the Fixed Series Compensation (FSC)is installed.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Enterprise Excellence is Inclusive Excellence.pdfKaiNexus
Enterprise excellence and inclusive excellence are closely linked, and real-world challenges have shown that both are essential to the success of any organization. To achieve enterprise excellence, organizations must focus on improving their operations and processes while creating an inclusive environment that engages everyone. In this interactive session, the facilitator will highlight commonly established business practices and how they limit our ability to engage everyone every day. More importantly, though, participants will likely gain increased awareness of what we can do differently to maximize enterprise excellence through deliberate inclusion.
What is Enterprise Excellence?
Enterprise Excellence is a holistic approach that's aimed at achieving world-class performance across all aspects of the organization.
What might I learn?
A way to engage all in creating Inclusive Excellence. Lessons from the US military and their parallels to the story of Harry Potter. How belt systems and CI teams can destroy inclusive practices. How leadership language invites people to the party. There are three things leaders can do to engage everyone every day: maximizing psychological safety to create environments where folks learn, contribute, and challenge the status quo.
Who might benefit? Anyone and everyone leading folks from the shop floor to top floor.
Dr. William Harvey is a seasoned Operations Leader with extensive experience in chemical processing, manufacturing, and operations management. At Michelman, he currently oversees multiple sites, leading teams in strategic planning and coaching/practicing continuous improvement. William is set to start his eighth year of teaching at the University of Cincinnati where he teaches marketing, finance, and management. William holds various certifications in change management, quality, leadership, operational excellence, team building, and DiSC, among others.
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RMD24 | Debunking the non-endemic revenue myth Marvin Vacquier Droop | First ...BBPMedia1
Marvin neemt je in deze presentatie mee in de voordelen van non-endemic advertising op retail media netwerken. Hij brengt ook de uitdagingen in beeld die de markt op dit moment heeft op het gebied van retail media voor niet-leveranciers.
Retail media wordt gezien als het nieuwe advertising-medium en ook mediabureaus richten massaal retail media-afdelingen op. Merken die niet in de betreffende winkel liggen staan ook nog niet in de rij om op de retail media netwerken te adverteren. Marvin belicht de uitdagingen die er zijn om echt aansluiting te vinden op die markt van non-endemic advertising.
What are the main advantages of using HR recruiter services.pdfHumanResourceDimensi1
HR recruiter services offer top talents to companies according to their specific needs. They handle all recruitment tasks from job posting to onboarding and help companies concentrate on their business growth. With their expertise and years of experience, they streamline the hiring process and save time and resources for the company.
What is the TDS Return Filing Due Date for FY 2024-25.pdfseoforlegalpillers
It is crucial for the taxpayers to understand about the TDS Return Filing Due Date, so that they can fulfill your TDS obligations efficiently. Taxpayers can avoid penalties by sticking to the deadlines and by accurate filing of TDS. Timely filing of TDS will make sure about the availability of tax credits. You can also seek the professional guidance of experts like Legal Pillers for timely filing of the TDS Return.
RMD24 | Retail media: hoe zet je dit in als je geen AH of Unilever bent? Heid...BBPMedia1
Grote partijen zijn al een tijdje onderweg met retail media. Ondertussen worden in dit domein ook de kansen zichtbaar voor andere spelers in de markt. Maar met die kansen ontstaan ook vragen: Zelf retail media worden of erop adverteren? In welke fase van de funnel past het en hoe integreer je het in een mediaplan? Wat is nu precies het verschil met marketplaces en Programmatic ads? In dit half uur beslechten we de dilemma's en krijg je antwoorden op wanneer het voor jou tijd is om de volgende stap te zetten.
Discover the innovative and creative projects that highlight my journey throu...dylandmeas
Discover the innovative and creative projects that highlight my journey through Full Sail University. Below, you’ll find a collection of my work showcasing my skills and expertise in digital marketing, event planning, and media production.
Putting the SPARK into Virtual Training.pptxCynthia Clay
This 60-minute webinar, sponsored by Adobe, was delivered for the Training Mag Network. It explored the five elements of SPARK: Storytelling, Purpose, Action, Relationships, and Kudos. Knowing how to tell a well-structured story is key to building long-term memory. Stating a clear purpose that doesn't take away from the discovery learning process is critical. Ensuring that people move from theory to practical application is imperative. Creating strong social learning is the key to commitment and engagement. Validating and affirming participants' comments is the way to create a positive learning environment.
3.0 Project 2_ Developing My Brand Identity Kit.pptxtanyjahb
A personal brand exploration presentation summarizes an individual's unique qualities and goals, covering strengths, values, passions, and target audience. It helps individuals understand what makes them stand out, their desired image, and how they aim to achieve it.
Unveiling the Secrets How Does Generative AI Work.pdfSam H
At its core, generative artificial intelligence relies on the concept of generative models, which serve as engines that churn out entirely new data resembling their training data. It is like a sculptor who has studied so many forms found in nature and then uses this knowledge to create sculptures from his imagination that have never been seen before anywhere else. If taken to cyberspace, gans work almost the same way.
As a business owner in Delaware, staying on top of your tax obligations is paramount, especially with the annual deadline for Delaware Franchise Tax looming on March 1. One such obligation is the annual Delaware Franchise Tax, which serves as a crucial requirement for maintaining your company’s legal standing within the state. While the prospect of handling tax matters may seem daunting, rest assured that the process can be straightforward with the right guidance. In this comprehensive guide, we’ll walk you through the steps of filing your Delaware Franchise Tax and provide insights to help you navigate the process effectively.
Memorandum Of Association Constitution of Company.pptseri bangash
www.seribangash.com
A Memorandum of Association (MOA) is a legal document that outlines the fundamental principles and objectives upon which a company operates. It serves as the company's charter or constitution and defines the scope of its activities. Here's a detailed note on the MOA:
Contents of Memorandum of Association:
Name Clause: This clause states the name of the company, which should end with words like "Limited" or "Ltd." for a public limited company and "Private Limited" or "Pvt. Ltd." for a private limited company.
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Registered Office Clause: It specifies the location where the company's registered office is situated. This office is where all official communications and notices are sent.
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C0212014018
1. The International Journal Of Engineering And Science (IJES)
|| Volume || 2 || Issue || 12 || Pages || 14-18 || 2013 ||
ISSN (e): 2319 – 1813 ISSN (p): 2319 – 1805
The Restricted Earth Fault Relay Operation: Impact of Current
Transformer Knee Point Voltages
Udoh, Benjamin E.
Department of Electrical/Electronic Engineering Federal Polytechnic Mubi Adamawa State, Nigeria
-------------------------------------------------------ABSTRACT--------------------------------------------------In this paper, the characteristic of current transformer (CT) magnetization curves are used to determine the
performance of restricted earth fault (REF) relays. This study was carried out at the150MVA 330/132/33kV
Gombe transmission substation. This is based on the field data obtained for the neutral current transformers
(NCTs) servicing the 150 MVA 330/132/33kV and 15MVA 132/33kV power transformers at the substation. From
the study, the knee-point voltages from the CT magnetization curves justify the voltage settings of the restricted
earth fault relays.
Keywords: Magnetization curve, Neutral current transformer, Restricted earth fault
--------------------------------------------------------------------------------------------------------------------------Date of Submission: 30 November 2013
Date of Acceptance: 28 December 13
--------------------------------------------------------------------------------------------------------------------------I.
INTRODUCTION
The magnetization currents of current transformers usually affect the overall setting of a protection
system. The effect may not be significant in the case of over current relays, but the effect can be seen in earth
fault relays and unit protection systems where large number of current transformers are connected together.
Because of the low setting of the restricted earth fault (REF) scheme the effect of current transformer (CT)
magnetization current is easily pronounced in the operation of its relays [1]. It is a well known fact that CT core
saturation is brought about by CT magnetization current on application of a voltage, when such voltage exceeds
its knee point value. Hence when considering the performance to be expected from a given CT, the exciting
current can be measured at various values of EMF. For this reason it is usually more convenient to apply a
varying voltage to the secondary winding, the primary winding being open circuited. Fig. 1 shows a typical
relationship. The point K on the curve is called the ‘Knee Point’, and is defined as the point in which an increase
of 10% in the exciting voltage of rated frequency produces an increase of 50% in the exciting current [2]. From
the curve in Fig. 1 point ‘A’ is known as the Ankle Point and the linear portion of the curve is between points
‘A’ and ‘K’.
V
Figure 1: Typical CT Magnetization Curve
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2. The Restricted Earth Fault Relay Operation: Impact of Current Transformer Knee Point Voltages
The restricted earth fault (REF) protection scheme refers to the differential protection of transformers
against ground (earth) fault. It is called “restricted” because its zone of protection is limited only to the windings
of the transformer. The restricted earth fault protection scheme is designed to take care of internal earth fault on
transformer windings, which if omitted could cause the windings of such transformer to be damaged in the event
of such fault. Since power transformers are one of the most important and most expensive components of
transmission and distribution networks, it is very essential to prevent a scenario where this piece of equipment is
being put out of service. If such an event occurs, the implication will be long period of power outage which
according to [3] will generate unpleasant situations such as property loss and business disruption leading to loss
orders, damaged to perishable goods and inventories for businesses. Since the issue of lack of adequate
restricted earth fault for power transformer protection cannot be compromised, the REF relay must be made to
operate satisfactorily by ensuring adequate setting of the relay voltage. The relay voltage must be made to fall
within the linear portion of the CT magnetization curves for proper operation of the relays. In this regard, [4]
pointed out that to ensure satisfactory operation of the restricted earth fault relay under internal fault conditions,
the CT knee point voltage should not be less than twice the relay voltage setting. The relay will never operate
with the required speed if the knee point voltage is just in excess of the relay voltage setting and not double the
value at least [5]. The CT will normally transform the fault current of the electrical power system for operation
of the protection relays connected to the secondary of that CT. If the core of the CT becomes saturated at a
lower value of primary current, as in the case of metering CTs, the system fault will not reflect properly to the
secondary terminals, which may cause the relays to remain inoperative even when the fault level of the power
system is large enough. That is why the core of the protection CT is made in such a way that the saturation level
of that core must be high enough, but still with a limit that is not too high otherwise, total transformation of
primary current during huge fault may badly damage the protection relays.
The restricted earth fault (REF) protection schemes are particularly noted for their high speed of
operation; hence they are readily applied in the protection of high voltage systems where fast fault clearing is a
premium. This is made possible by the use of an instantaneous attracted armature type of relay. An internal earth
fault within a transformer could cause serious damage to the system and this has to be cleared instantaneously
[6]. Also high speed fault clearing is particularly beneficial for faults near large concentrations of generation and
long intertie lines to remote sources of generation. This is so because fault causes strong angular acceleration to
nearby generators, which in turn causes a reduction in plant output due to voltage suppression during fault [7].
Hence the knee point voltages of CTs servicing the REF relays protecting high voltage power transformers
should be of higher values, which must be multiples of the relay voltage setting and must be carefully chosen so
that the relay could function adequately in clearing its fault speedily. With high speed protection, it is desirable
that the transformer should not saturate when carrying maximum current caused by a fault at the critical point of
measurement. Where this is not possible, saturation would cause a reduction in the secondary current and
therefore reduces the reach of the instantaneous relay [8].
II.
RESEARCH METHOD AND ANALYSIS
The magnetization data for this study were obtained from the record of injection tests of the neutral
current transformers (NCTs) servicing the two 150MVA 330/132/33kV and the two 15MVA 132/33kV power
transformer at the substation under study. The data are presented in Tables (1) to (4). They were analyzed using
an engineering software programme known as Micro cal – Origin 5.0 adapted for power system simulation.
2.1 Data Analysis
The principle of the high impedance (REF) scheme is applied, and to do so the following assumptions are made.
1. One current transformer (or set of it) completely saturates and ceases to transform any part of the
primary fault current since its excitation impedance is negligible.
2. The whole of the primary fault current is perfectly transformed by the remaining current transformers.
3. The resistance of the secondary winding of the saturated current transformer together with the leads
connecting it constitutes the only burden in parallel with the relay.
Consistent with the above assumptions, the maximum voltage across the relay is calculated using:
VR
Where:
=
If (RCT + 2RL)
If
RCT
RL
=
=
=
Maximum through fault secondary current
CT secondary winding resistance
Maximum lead resistance from CT to the relay circuit terminals
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(1)
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3. The Restricted Earth Fault Relay Operation: Impact of Current Transformer Knee Point Voltages
In order to ensure satisfactory operations of the relay under internal fault conditions the CT knee point
voltage should not be less than twice the relay voltage setting, thus:
VK
=
2VR
(2)
Where:
VR
=
Relay voltage setting
The values of the knee point voltages are shown in Table 7 under the column “Calculated Value”.
III.
RESULTS AND DISCUSSIONS
Table 7 shows the relay voltage settings for the various power transformers and their corresponding
knee point voltages based on equation (2). The Table shows the calculated and the actual values at the
substation. The actual values are the minimum allowable setting values of the relays, in which case the values
could be increased to meet the local condition to which the relays are operational. For example, the actual value
of knee point voltage of 200V for the relay voltage setting of 100V as against 40V for the relay voltage of 20V
(calculated value) with respect to the 330/132/33kV power transformers is practically chosen by the substation
under study, as a means of preventing system mal-operation when fault occur outside the protected zone. This
observation is in order because one of the benefits of the high impedance restricted earth fault relay operation, is
the ability for the system to maintain stability when the voltage setting of the relay is greater than the maximum
voltage which can appear under a given through fault condition [9, 10].
Figs. 2 to 5 give the magnetization curves for the neutral current transformers servicing the REF relays
at the substation. The curves give a true picture of the magnetization characteristics from which the knee point
voltages are estimated. From the magnetization curve of Fig. 2, the knee point voltage is about 450V as against
the calculated value of 200V in Table 7. This knee point voltage of 450V estimated from the curve is a preferred
value than the 200V calculated directly from equation (2), and gives a higher multiple of the 100V relay voltage
setting. This shows that the performance of the neutral current transformer servicing the REF relay protecting
the 150MVA 330/132/33kV power transformer is good because the 100V relay setting falls within the linear
portion of the CT magnetization curve. From this it is quite certain that the neutral current transformer (NCT)
will never get saturated in the event of any through fault condition or when there is an internal earth fault [8].
All the values of the neutral current transformers (NCTs) knee point voltages as estimated from the
magnetization curves of Figs 2 to 5 are presented in Table 7. From the Table, the knee point voltage of the NCT
servicing the REF relay protecting transformer T2A is lower than the rest. It is on record that the windings of
that particular transformer were damaged some few years ago as a result of an inadequate restricted earth fault
protection, which plunged the whole of the North East region into total darkness for a period of six (6) months.
The whole set was replaced by the end of that year. It was the transformer failure that prompted this study.
It should be noted that the estimated values of the knee point voltages from the magnetization curves
give the actual operational condition of the neutral current transformers (NCTs) at the substation. They also
provide useful guides into the efficient operation of the REF relays in terms of speed [5]. On the other hand, the
calculated values of the knee point voltages directly from the formula as presented in this paper are used as
checks to determine the reliabilities of the estimated values from the curves. They do not describe the operating
condition of the NCTs.
IV.
CONCLUSION
The operational abilities of relays are sometimes affected by the magnetization characteristics of the
CTs servicing such relays. In this study, the knee point voltages that were determined from the magnetization
characteristics of the neutral current transformers have been found to be quite adequate in guaranteeing effective
operation of the restricted earth fault relays. This is so because the neutral current transformers have favourable
linear portion in their magnetization characteristics, which is a necessary requirement in the proper operation of
the relays, especially when it has to do with high voltage power systems. From the observation made in this
study, it will be safe to recommend that NCTs with high value knee point voltages should always be used to
service REF relays protecting high voltage power systems.
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4. The Restricted Earth Fault Relay Operation: Impact of Current Transformer Knee Point Voltages
Table 1: Magnetization Data for T1A 150MVA 330/132/33kV Transformer NCT
Slated
Voltage
(V)
Neutral
Current
(mA)
Neutral
REF
CT
50
100
150
200
220
240
260
1.82
3.00
4.00
5.00
5.20
5.50
6.00
Table 2: Magnetization Data for T2A 150MVA 330/132/33kV Transformer NCT
Slated Voltage
(V)
50
100
150
200
220
240
260
1.75
Neutral
REF
CT
2.50
3.25
4.25
4.50
5.00
5.50
Neutral Current (mA)
Table 3: Magnetization Data for T1 15MVA 132/33kV Transformer NCT
Slated Voltage (V)
50
100
150
200
220
233
4.00
Neutral REF CT
7.00
9.75
12.25
13.25
14.00
Neutral Current (mA)
Table 4: Magnetization Data for T2 15MVA 132/33kV Transformer NCT
Slated Voltage (V)
50
100
150
200
220
233
5.00
Neutral REF CT
9.00
12.75
16.00
17.40
18.30
Neutral Current (mA)
Table 5: 150MVA 330/132/33kV Power Transformer Data
Secondary winding resistance (RCT)
5.8 Ohms
Maximum lead resistance (RL) from CT to the relay tapping point
0.54 Ohms
Percentage reactance (X)
11.53%
Current Transformer ratio
800/1A
Type: Star/Delta/Star
Table 6: 15MVA 132/33kV Power Transformer Data
Secondary winding resistance (RCT)
2.3 Ohms
Maximum lead resistance (RL) from CT to the relay tapping point
0.4 Ohms
Percentage reactance (X)
5.17%
Current Transformer ratio
600/1A
Type: Star/Delta
Table 7: Results of NCTs Knee Point Voltages Associated with the Power Transformers
Power
Transformer
T1A
T2A
T1
T2
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Calculated Value
REF Relay
Knee Point
Voltage (V)
Voltage (V)
20
20
15
15
Actual Value
REF Relay
Knee Point
Voltage (V)
Voltage (V)
40
40
30
30
100
100
-
The IJES
200
200
-
NCT Knee
Point Voltage
From Curve (V)
450
280
400
480
Page 17
5. The Restricted Earth Fault Relay Operation: Impact of Current Transformer Knee Point Voltages
Figure 2: Magnetization curve for neutral
CT of transformer T1A
Figure 4: Magnetization curve for neutral
CT of transformer T1
Figure 3: Magnetization curve for neutral
CT of transformer T2A
Figure 5: Magnetization curve for neutral
CT of transformer T2
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[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
Udoh, B. E., Evaluation of Restricted earth fault protection scheme for power transformers at Gombe
Transmission substation, unpublished M. Eng thesis, Abubakar Tafawa Belewa university, Bauchi – Nigeria
2002.
Electricity Training Association, Power system protection, vol. 1 (Peter Peregrinus Limited, 1995).
Campbell, Richard J., Weather related power outages and electric system resiliency, Congressional research
service report for United States congress, August 2012.
GEC Measurements, High stability circulating current relay (General Electric Company Ltd, England, 1982).
Davis, T., Protection of industrial power systems (Pergamos Press Ltd, 1984).
NEPA, Protection of transformer (NEPA zonal training center, Jos – Nigeria, 1998).
Berglund, R. O. et al, One cycle fault interruption at 500kV: system benefits and breaker design, IEEE transaction
On PAS, 93(5), 1974.
Cooper, W. F. and Jones, D. A. D., Electric safety engineering (3rd ed., Newness, 1993).
Franklin, A. C. and Franklin, D. P., The J and P Transformer book (11th ed., Butterworths, 1983).
Wright, A. and Christopoulos, C., Electric power system protection (Wiley and Sons, 1993).
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