Power systems are subject to a wide range of small or large disturbances during operating conditions. Small changes in loading conditions occur continually. The power system must adjust to these changing conditions and continue to operate satisfactorily and within the desired limits of voltage and frequency. The power system should be designed to survive larger types of disturbances, such as faults, loss of a large generator, or line switching. Certain system disturbances may cause loss of synchronism between a generator and rest of the utility system, or between interconnected power systems of neighboring utilities. If such a loss of synchronism occurs, it is imperative that the generator or system areas operating asynchronously are separated immediately to avoid widespread outages and equipment damage. Here it is described to distinguish between power swing and real fault. It is also discussed recent enhancements in the design of out of step tripping and blocking protection functions that improve the security and reliability of the power system. In addition to that the behavior of distance relay element during power swing and during fault is simulated using MATLAB and SIMULINK simulations.
he main purpose of transient stability studies is to determineThe main purpose of transient stability studies is to determine
whether a system will remain in synchronism following major
disturbances such as transmission system faults, sudden load
changes, loss of generating units, or line switching.
Classification Of Power System StabilityAravind Shaji
The Slide Deals With Power System Stability. Contents Include
Power System Stability Overview
Power System Stability: A Proposed Definition
Need of Stability Classification
Classification of stability
Power System Stability Classification
Rotor Angle Stability
Voltage Stability
Frequency Stability
Rotor Angle Stability vs. Voltage Stability
References
Transient stability analysis on a multi machine system in psateSAT Journals
Abstract
Modern power system are subject to large disturbances such as three phase short circuit faults. When a fault occurs on a system
the generators rotor angle becomes unstable and thus it losses synchronism with the system and it becomes unstable. Thus
transient stability analysis can be performed on a system in order to understand the generators performance when subjected to a
short circuit fault. When the system is subjected to a fault the generator experiences transient oscillations in rotor speed and
angle which can be effectively suppressed with the incorporation of Automatic Voltage Regulator (AVR) and Power System
Stabilizer (PSS). The simulations have been performed using the MATLAB/PSAT software.
Keywords—Transient stability, Three phase fault Faults, AVR, PSS.
INTRODUCTION TO POWER SYSTEM STABILITY BY Kundur Power Systems SolutionsPower System Operation
Power System Stability denotes the ability of an electric power system, for a given initial operating condition, to regain a state of operating equilibrium after being subjected to a physical disturbance, with all system variables bounded so that the system integrity is preserved
Integrity of the system is preserved when practically the entire power system remains intact with no tripping of generators or loads, except for those disconnected by isolation of the faulted elements or intentionally tripped to preserve the continuity of operation of the rest of the system
Stability is a condition of equilibrium between opposing forces:
instability results when a disturbance leads to a sustained imbalance between the opposing forces
instability is a run-away or run-down situation
he main purpose of transient stability studies is to determineThe main purpose of transient stability studies is to determine
whether a system will remain in synchronism following major
disturbances such as transmission system faults, sudden load
changes, loss of generating units, or line switching.
Classification Of Power System StabilityAravind Shaji
The Slide Deals With Power System Stability. Contents Include
Power System Stability Overview
Power System Stability: A Proposed Definition
Need of Stability Classification
Classification of stability
Power System Stability Classification
Rotor Angle Stability
Voltage Stability
Frequency Stability
Rotor Angle Stability vs. Voltage Stability
References
Transient stability analysis on a multi machine system in psateSAT Journals
Abstract
Modern power system are subject to large disturbances such as three phase short circuit faults. When a fault occurs on a system
the generators rotor angle becomes unstable and thus it losses synchronism with the system and it becomes unstable. Thus
transient stability analysis can be performed on a system in order to understand the generators performance when subjected to a
short circuit fault. When the system is subjected to a fault the generator experiences transient oscillations in rotor speed and
angle which can be effectively suppressed with the incorporation of Automatic Voltage Regulator (AVR) and Power System
Stabilizer (PSS). The simulations have been performed using the MATLAB/PSAT software.
Keywords—Transient stability, Three phase fault Faults, AVR, PSS.
INTRODUCTION TO POWER SYSTEM STABILITY BY Kundur Power Systems SolutionsPower System Operation
Power System Stability denotes the ability of an electric power system, for a given initial operating condition, to regain a state of operating equilibrium after being subjected to a physical disturbance, with all system variables bounded so that the system integrity is preserved
Integrity of the system is preserved when practically the entire power system remains intact with no tripping of generators or loads, except for those disconnected by isolation of the faulted elements or intentionally tripped to preserve the continuity of operation of the rest of the system
Stability is a condition of equilibrium between opposing forces:
instability results when a disturbance leads to a sustained imbalance between the opposing forces
instability is a run-away or run-down situation
Small-Signal (or Small Disturbance) Stability is the ability of a power system to maintain synchronism when subjected to small disturbances
such disturbances occur continually on the system due to small variations in loads and generation
disturbance considered sufficiently small if linearization of system equations is permissible for analysis
Corresponds to Liapunov's first method of stability analysis
Small-signal analysis using powerful linear analysis techniques provides valuable information about the inherent dynamic characteristics of the power system and assists in its robust design
The ability of the power system to maintain synchronous operation when subjected to a severe transient disturbance
faults on transmission circuits, transformers, buses
loss of generation
loss of loads
Response involves large excursions of generator rotor angles: influenced by nonlinear power-angle relationship
Stability depends on both the initial operating state of the system and the severity of the disturbance
Post-disturbance steady-state operating conditions usually differ from pre-disturbance conditions
This presentation is about power system voltage stability.
What is voltage stability?
How voltage instability occurs?
How to improve voltage stability of the system?
Random events & other changes such as random variation in loads continually excite low frequency electromechanical oscillations within the power system which are continually observable in the power system measurements such as those obtained from PMUs. These oscillations also happen to characterize the Small Signal or Oscillatory Stability which is a measure of the power system’s ability to maintain synchronism under small disturbances, and is usually associated with power system’s inability to dampen such oscillations. Damping of these oscillations (typically expressed in %) is therefore a measure of the grid’s robustness to withstand small events or gradual changes in the system. For example, 10% damping implies that the oscillations will decay out in 10 oscillatory cycles while 20 % damping implies that these oscillations will die out in 5 oscillatory cycles (thus higher damping suggests greater robustness and a better ability to mitigate oscillations).
DYNAMIC STABILITY ANALYSIS (Small Signal Stability) – 1
Small-Signal Stability of Multi-machine Systems
Special techniques for analysis of very large systems
Characteristics of Small-Signal Stability Problems
Local problems
Global problems
DYNAMIC STABILITY ANALYSIS – 2
Introduction
Overview of the Proposed Method
Generating Unit
Synchronous Machine
Calculation of Equilibrium State Conditions
Excitation and Governor Control Systems
Excitation System
Turbine-Governor System
Combined Model of Generating Unit
Transient Stability Assessment and Enhancement in Power SystemIJMER
Power system is subjected to sudden changes in load levels. Stability is an important concept
which determines the stable operation of power system. For the improvement of transient stability the
general methods adopted are fast acting exciters, circuit breakers and reduction in system transfer
reactance. The modern trend is to employ FACTS devices in the existing system for effective utilization
of existing transmission resources. The critical clearing time is a measure to assess transient instability.
Using PSAT, the critical clearing time (CCT) corresponding to various faults are calculated. The most
critical faults were identified using this calculation. The CCT for the critical faults were found to change
with change in operating point. The CCT values are predicted using Artificial Neural Network (ANN) to
study the training effects of ANN. TCSC is selected as the FACTS device for transient stability
enhancement. Particle Swarm Optimization method is used to find the optimal position of TCSC using
the objective function real power loss minimization. The result shows that the technique effectively
increases the transient stability of the system
Power System Stability
Power system stability is the ability of an electric power
system, for a given initial operating condition, to regain a
state of operating equilibrium after being subjected to a
physical disturbance, with most system variables bounded
so that practically the entire system remains intact.
A Performance Analysis of Statcom on Distance Protection RelayIJSRD
Legacy Transmission system protection schemes are mainly based on distance relaying. However, performance of distance relay is affected in presence of shunt Flexible AC Transmission System Devices (FACTS) like Static synchronous Compensator (STATCOM) which are mostly used to enhance the transferring capacity of transmission system. The study about the protection system like transmission protection by using Distance Relay Specially mho relay and its zone wise tripping characteristics. The detailed idea about FACTS, type of FACTS, Advantages of FACTS and application of FACTS. For various purpose like power handling capacity by injecting or absorbing reactive power. The STATCOM has adverse effect on protection like distance protection ,distance relay mal-function when STATCOM is connected to the Line, when STATCOM is in fault loop then have a great impact on relay tripping characteristics. Distance relay simulation in MATLAB plays an important role.
Small-Signal (or Small Disturbance) Stability is the ability of a power system to maintain synchronism when subjected to small disturbances
such disturbances occur continually on the system due to small variations in loads and generation
disturbance considered sufficiently small if linearization of system equations is permissible for analysis
Corresponds to Liapunov's first method of stability analysis
Small-signal analysis using powerful linear analysis techniques provides valuable information about the inherent dynamic characteristics of the power system and assists in its robust design
The ability of the power system to maintain synchronous operation when subjected to a severe transient disturbance
faults on transmission circuits, transformers, buses
loss of generation
loss of loads
Response involves large excursions of generator rotor angles: influenced by nonlinear power-angle relationship
Stability depends on both the initial operating state of the system and the severity of the disturbance
Post-disturbance steady-state operating conditions usually differ from pre-disturbance conditions
This presentation is about power system voltage stability.
What is voltage stability?
How voltage instability occurs?
How to improve voltage stability of the system?
Random events & other changes such as random variation in loads continually excite low frequency electromechanical oscillations within the power system which are continually observable in the power system measurements such as those obtained from PMUs. These oscillations also happen to characterize the Small Signal or Oscillatory Stability which is a measure of the power system’s ability to maintain synchronism under small disturbances, and is usually associated with power system’s inability to dampen such oscillations. Damping of these oscillations (typically expressed in %) is therefore a measure of the grid’s robustness to withstand small events or gradual changes in the system. For example, 10% damping implies that the oscillations will decay out in 10 oscillatory cycles while 20 % damping implies that these oscillations will die out in 5 oscillatory cycles (thus higher damping suggests greater robustness and a better ability to mitigate oscillations).
DYNAMIC STABILITY ANALYSIS (Small Signal Stability) – 1
Small-Signal Stability of Multi-machine Systems
Special techniques for analysis of very large systems
Characteristics of Small-Signal Stability Problems
Local problems
Global problems
DYNAMIC STABILITY ANALYSIS – 2
Introduction
Overview of the Proposed Method
Generating Unit
Synchronous Machine
Calculation of Equilibrium State Conditions
Excitation and Governor Control Systems
Excitation System
Turbine-Governor System
Combined Model of Generating Unit
Transient Stability Assessment and Enhancement in Power SystemIJMER
Power system is subjected to sudden changes in load levels. Stability is an important concept
which determines the stable operation of power system. For the improvement of transient stability the
general methods adopted are fast acting exciters, circuit breakers and reduction in system transfer
reactance. The modern trend is to employ FACTS devices in the existing system for effective utilization
of existing transmission resources. The critical clearing time is a measure to assess transient instability.
Using PSAT, the critical clearing time (CCT) corresponding to various faults are calculated. The most
critical faults were identified using this calculation. The CCT for the critical faults were found to change
with change in operating point. The CCT values are predicted using Artificial Neural Network (ANN) to
study the training effects of ANN. TCSC is selected as the FACTS device for transient stability
enhancement. Particle Swarm Optimization method is used to find the optimal position of TCSC using
the objective function real power loss minimization. The result shows that the technique effectively
increases the transient stability of the system
Power System Stability
Power system stability is the ability of an electric power
system, for a given initial operating condition, to regain a
state of operating equilibrium after being subjected to a
physical disturbance, with most system variables bounded
so that practically the entire system remains intact.
A Performance Analysis of Statcom on Distance Protection RelayIJSRD
Legacy Transmission system protection schemes are mainly based on distance relaying. However, performance of distance relay is affected in presence of shunt Flexible AC Transmission System Devices (FACTS) like Static synchronous Compensator (STATCOM) which are mostly used to enhance the transferring capacity of transmission system. The study about the protection system like transmission protection by using Distance Relay Specially mho relay and its zone wise tripping characteristics. The detailed idea about FACTS, type of FACTS, Advantages of FACTS and application of FACTS. For various purpose like power handling capacity by injecting or absorbing reactive power. The STATCOM has adverse effect on protection like distance protection ,distance relay mal-function when STATCOM is connected to the Line, when STATCOM is in fault loop then have a great impact on relay tripping characteristics. Distance relay simulation in MATLAB plays an important role.
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
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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.
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
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.
IRJET-Review on Power Quality Enhancement in weak Power Grids by Integration ...IRJET Journal
Prathmesh Mayekar, Mahesh Wagh, Nilkanth Shinde "Review on Power Quality Enhancement in weak Power Grids by Integration of Renewable Energy Technologies", International Research Journal of Engineering and Technology (IRJET), Volume2,issue-01 April 2015.e-ISSN:2395-0056, p-ISSN:2395-0072. www.irjet.net
Abstract
During Last decade power quality problems has become more complex at all level of power system. With the increased use of sophisticated electronics, high efficiency variable speed drive, power electronic controllers and also more & more non-linear loads, Power Quality has become an increasing concern to utilities and customers. The modern sensitive, Non-linear and sophisticated load affects the power quality. This paper deals with the issues of low power quality in weak power grids. Initially the various power quality issues are discussed with their definition or occurrence and then finally the solution to mitigate this power quality issues are discussed. The innovative solutions like integration of renewable energy systems along with energy storage to enhance power quality by interfacing with custom power devices are explained in detail. Nearly all sorts of solution for mitigating power quality issue require some sort of DC source for providing active power, which can be supplied by renewable energy source. Also the various energy storage systems are studied.
A Review on Suppression of Secondary Arc Current Trough Single-Phase Auto-Rec...paperpublications3
Abstract: When single-phase to ground fault occurs in high voltage transmission line, secondary arc current and recovery voltage must be suppressed in order to ensure that single-phase auto-reclosing operates reliably and successfully.
This work adopts the suppression measure of secondary arc current using shunt reactor with neutral small reactor-which is applied widely in India, and then uses MATLAB Simulink software to simulate suppression effect about different fault point locations toward an example of 735kv double-ended sources high-voltage transmission line. According to the simulation results, suppression effects about different locations are distinct. Moreover, this measure can suppress secondary arc current effectively, ensure success of single phase auto-reclosing operation and finally achieve security and stability of power system.
Due to availability of internet and evolution of embedded devices, Internet of things can be useful to contribute in energy domain. The Internet of Things (IoT) will deliver a smarter grid to enable more information and connectivity throughout the infrastructure and to homes. Through the IoT, consumers, manufacturers and utility providers will come across new ways to manage devices and ultimately conserve resources and save money by using smart meters, home gateways, smart plugs and connected appliances. The future smart home, various devices will be able to measure and share their energy consumption, and actively participate in house-wide or building wide energy management systems. This paper discusses the different approaches being taken worldwide to connect the smart grid. Full system solutions can be developed by combining hardware and software to address some of the challenges in building a smarter and more connected smart grid.
A Survey Report on : Security & Challenges in Internet of Thingsijsrd.com
In the era of computing technology, Internet of Things (IoT) devices are now popular in each and every domains like e-governance, e-Health, e-Home, e-Commerce, and e-Trafficking etc. Iot is spreading from small to large applications in all fields like Smart Cities, Smart Grids, Smart Transportation. As on one side IoT provide facilities and services for the society. On the other hand, IoT security is also a crucial issues.IoT security is an area which totally concerned for giving security to connected devices and networks in the IoT .As, IoT is vast area with usability, performance, security, and reliability as a major challenges in it. The growth of the IoT is exponentially increases as driven by market pressures, which proportionally increases the security threats involved in IoT The relationship between the security and billions of devices connecting to the Internet cannot be described with existing mathematical methods. In this paper, we explore the opportunities possible in the IoT with security threats and challenges associated with it.
In today’s emerging world of Internet, each and every thing is supposed to be in connected mode with the help of billions of smart devices. By connecting all the devises used in our day to day life, make our life trouble less and easy. We are incorporated in a world where we are used to have smart phones, smart cars, smart gadgets, smart homes and smart cities. Different institutes and researchers are working for creating a smart world for us but real question which we need to emphasis on is how to make dumb devises talk with uncommon hardware and communication technology. For the same what kind of mechanism to use with various protocols and less human interaction. The purpose is to provide the key area for application of IoT and a platform on which various devices having different mechanism and protocols can communicate with an integrated architecture.
Study on Issues in Managing and Protecting Data of IOTijsrd.com
This paper discusses variety of issues for preserving and managing data produced by IoT. Every second large amount of data are added or updated in the IoT databases across the heterogeneous environment. While managing the data each phase of data processing for IoT data is exigent like storing data, querying, indexing, transaction management and failure handling. We also refer to the problem of data integration and protection as data requires to be fit in single layout and travel securely as they arrive in the pool from diversified sources in different structure. Finally, we confer a standardized pathway to manage and to defend data in consistent manner.
Interactive Technologies for Improving Quality of Education to Build Collabor...ijsrd.com
Today with advancement in Information Communication Technology (ICT) the way the education is being delivered is seeing a paradigm shift from boring classroom lectures to interactive applications such as 2-D and 3-D learning content, animations, live videos, response systems, interactive panels, education games, virtual laboratories and collaborative research (data gathering and analysis) etc. Engineering is emerging with more innovative solutions in the field of education and bringing out their innovative products to improve education delivery. The academic institutes which were once hesitant to use such technology are now looking forward to such innovations. They are adopting the new ways as they are realizing the vast benefits of using such methods and technology. The benefits are better comprehensibility, improved learning efficiency of students, and access to vast knowledge resources, geographical reach, quick feedback, accountability and quality research. This paper focuses on how engineering can leverage the latest technology and build a collaborative learning environment which can then be integrated with the national e-learning grid.
Internet of Things - Paradigm Shift of Future Internet Application for Specia...ijsrd.com
In the world more than 15% people are living with disability that also include children below age of 10 years. Due to lack of independent support services specially abled (handicap) people overly rely on other people for their basic needs, that excludes them from being financially and socially active. The Internet of Things (IoT) can give support system and a better quality of life as well as participation in routine and day to day life. For this purpose, the future solutions for current problems has been introduced in this paper. Daunting challenges have been considered as future research and glimpse of the IoT for specially abled person is given in the paper.
A Study of the Adverse Effects of IoT on Student's Lifeijsrd.com
Internet of things (IoT) is the most powerful invention and if used in the positive direction, internet can prove to be very productive. But, now a days, due to the social networking sites such as Face book, WhatsApp, twitter, hike etc. internet is producing adverse effects on the student life, especially those students studying at college Level. As it is rightly said, something which has some positive effects also has some of the negative effects on the other hand. In this article, we are discussing some adverse effects of IoT on student’s life.
Pedagogy for Effective use of ICT in English Language Learningijsrd.com
The use of information and communications technology (ICT) in education is a relatively new phenomenon and it has been the educational researchers' focus of attention for more than two decades. Educators and researchers examine the challenges of using ICT and think of new ways to integrate ICT into the curriculum. However, there are some barriers for the teachers that prevent them to use ICT in the classroom and develop supporting materials through ICT. The purpose of this study is to examine the high school English teachers’ perceptions of the factors discouraging teachers to use ICT in the classroom.
In recent years usage of private vehicles create urban traffic more and more crowded. As result traffic becomes one of the important problems in big cities in all over the world. Some of the traffic concerns are traffic jam and accidents which have caused a huge waste of time, more fuel consumption and more pollution. Time is very important parameter in routine life. The main problem faced by the people is real time routing. Our solution Virtual Eye will provide the current updates as in the real time scenario of the specific route. This research paper presents smart traffic navigation system, based on Internet of Things, which is featured by low cost, high compatibility, easy to upgrade, to replace traditional traffic management system and the proposed system can improve road traffic tremendously.
Ontological Model of Educational Programs in Computer Science (Bachelor and M...ijsrd.com
In this work there is illustrated an ontological model of educational programs in computer science for bachelor and master degrees in Computer science and for master educational program “Computer science as second competence†by Tempus project PROMIS.
Understanding IoT Management for Smart Refrigeratorijsrd.com
Lately the concept of Internet of Things (IoT) is being more elaborated and devices and databases are proposed thereby to meet the need of an Internet of Things scenario. IoT is being considered to be an integral part of smart house where devices will be connected to each other and also react upon certain environmental input. This will eventually include the home refrigerator, air conditioner, lights, heater and such other home appliances. Therefore, we focus our research on the database part for such an IoT’ fridge which we called as smart Fridge. We describe the potentials achievable through a database for an IoT refrigerator to manage the refrigerator food and also aid the creation of a monthly budget of the house for a family. The paper aims at the data management issue based on a proposed design for an intelligent refrigerator leveraging the sensor technology and the wireless communication technology. The refrigerator which identifies products by reading the barcodes or RFID tags is proposed to order the required products by connecting to the Internet. Thus the goal of this paper is to minimize human interaction to maintain the daily life events.
DESIGN AND ANALYSIS OF DOUBLE WISHBONE SUSPENSION SYSTEM USING FINITE ELEMENT...ijsrd.com
Double wishbone designs allow the engineer to carefully control the motion of the wheel throughout suspension travel. 3-D model of the Lower Wishbone Arm is prepared by using CAD software for modal and stress analysis. The forces and moments are used as the boundary conditions for finite element model of the wishbone arm. By using these boundary conditions static analysis is carried out. Then making the load as a function of time; quasi-static analysis of the wishbone arm is carried out. A finite element based optimization is used to optimize the design of lower wishbone arm. Topology optimization and material optimization techniques are used to optimize lower wishbone arm design.
A Review: Microwave Energy for materials processingijsrd.com
Microwave energy is a latest largest growing technique for material processing. This paper presents a review of microwave technologies used for material processing and its use for industrial applications. Advantages in using microwave energy for processing material include rapid heating, high heating efficiency, heating uniformity and clean energy. The microwave heating has various characteristics and due to which it has been become popular for heating low temperature applications to high temperature applications. In recent years this novel technique has been successfully utilized for the processing of metallic materials. Many researchers have reported microwave energy for sintering, joining and cladding of metallic materials. The aim of this paper is to show the use of microwave energy not only for non-metallic materials but also the metallic materials. The ability to process metals with microwave could assist in the manufacturing of high performance metal parts desired in many industries, for example in automotive and aeronautical industries.
Web Usage Mining: A Survey on User's Navigation Pattern from Web Logsijsrd.com
With an expontial growth of World Wide Web, there are so many information overloaded and it became hard to find out data according to need. Web usage mining is a part of web mining, which deal with automatic discovery of user navigation pattern from web log. This paper presents an overview of web mining and also provide navigation pattern from classification and clustering algorithm for web usage mining. Web usage mining contain three important task namely data preprocessing, pattern discovery and pattern analysis based on discovered pattern. And also contain the comparative study of web mining techniques.
APPLICATION OF STATCOM to IMPROVED DYNAMIC PERFORMANCE OF POWER SYSTEMijsrd.com
Application of FACTS controller called Static Synchronous Compensator STATCOM to improve the performance of power grid with Wind Farms is investigated .The essential feature of the STATCOM is that it has the ability to absorb or inject fastly the reactive power with power grid . Therefore the voltage regulation of the power grid with STATCOM FACTS device is achieved. Moreover restoring the stability of the power system having wind farm after occurring severe disturbance such as faults or wind farm mechanical power variation is obtained with STATCOM controller . The dynamic model of the power system having wind farm controlled by proposed STATCOM is developed . To validate the powerful of the STATCOM FACTS controller, the studied power system is simulated and subjected to different severe disturbances. The results prove the effectiveness of the proposed STATCOM controller in terms of fast damping the power system oscillations and restoring the power system stability.
Making model of dual axis solar tracking with Maximum Power Point Trackingijsrd.com
Now a days solar harvesting is more popular. As the popularity become higher the material quality and solar tracking methods are more improved. There are several factors affecting the solar system. Major influence on solar cell, intensity of source radiation and storage techniques The materials used in solar cell manufacturing limit the efficiency of solar cell. This makes it particularly difficult to make considerable improvements in the performance of the cell, and hence restricts the efficiency of the overall collection process. Therefore, the most attainable maximum power point tracking method of improving the performance of solar power collection is to increase the mean intensity of radiation received from the source used. The purposed of tracking system controls elevation and orientation angles of solar panels such that the panels always maintain perpendicular to the sunlight. The measured variables of our automatic system were compared with those of a fixed angle PV system. As a result of the experiment, the voltage generated by the proposed tracking system has an overall of about 28.11% more than the fixed angle PV system. There are three major approaches for maximizing power extraction in medium and large scale systems. They are sun tracking, maximum power point (MPP) tracking or both.
A REVIEW PAPER ON PERFORMANCE AND EMISSION TEST OF 4 STROKE DIESEL ENGINE USI...ijsrd.com
In day today's relevance, it is mandatory to device the usage of diesel in an economic way. In present scenario, the very low combustion efficiency of CI engine leads to poor performance of engine and produces emission due to incomplete combustion. Study of research papers is focused on the improvement in efficiency of the engine and reduction in emissions by adding ethanol in a diesel with different blends like 5%, 10%, 15%, 20%, 25% and 30% by volume. The performance and emission characteristics of the engine are tested observed using blended fuels and comparative assessment is done with the performance and emission characteristics of engine using pure diesel.
Study and Review on Various Current Comparatorsijsrd.com
This paper presents study and review on various current comparators. It also describes low voltage current comparator using flipped voltage follower (FVF) to obtain the single supply voltage. This circuit has short propagation delay and occupies a small chip area as compare to other current comparators. The results of this circuit has obtained using PSpice simulator for 0.18 μm CMOS technology and a comparison has been performed with its non FVF counterpart to contrast its effectiveness, simplicity, compactness and low power consumption.
Reducing Silicon Real Estate and Switching Activity Using Low Power Test Patt...ijsrd.com
Power dissipation is a challenging problem for today's system-on-chip design and test. This paper presents a novel architecture which generates the test patterns with reduced switching activities; it has the advantage of low test power and low hardware overhead. The proposed LP-TPG (test pattern generator) structure consists of modified low power linear feedback shift register (LP-LFSR), m-bit counter, gray counter, NOR-gate structure and XOR-array. The seed generated from LP-LFSR is EXCLUSIVE-OR ed with the data generated from gray code generator. The XOR result of the sequence is single input changing (SIC) sequence, in turn reduces the switching activity and so power dissipation will be very less. The proposed architecture is simulated using Modelsim and synthesized using Xilinx ISE9.2.The Xilinx chip scope tool will be used to test the logic running on FPGA.
Defending Reactive Jammers in WSN using a Trigger Identification Service.ijsrd.com
In the last decade, the greatest threat to the wireless sensor network has been Reactive Jamming Attack because it is difficult to be disclosed and defend as well as due to its mass destruction to legitimate sensor communications. As discussed above about the Reactive Jammers Nodes, a new scheme to deactivate them efficiently is by identifying all trigger nodes, where transmissions invoke the jammer nodes, which has been proposed and developed. Due to this identification mechanism, many existing reactive jamming defending schemes can be benefited. This Trigger Identification can also work as an application layer .In this paper, on one side we provide the several optimization problems to provide complete trigger identification service framework for unreliable wireless sensor networks and on the other side we also provide an improved algorithm with regard to two sophisticated jamming models, in order to enhance its robustness for various network scenarios.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
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It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
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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.
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Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
1. IJSRD - International Journal for Scientific Research & Development| Vol. 1, Issue 5, 2013 | ISSN (online): 2321-0613
All rights reserved by www.ijsrd.com 1192
Abstract— Power systems are subject to a wide range of
small or large disturbances during operating conditions.
Small changes in loading conditions occur continually. The
power system must adjust to these changing conditions and
continue to operate satisfactorily and within the desired
limits of voltage and frequency. The power system should
be designed to survive larger types of disturbances, such as
faults, loss of a large generator, or line switching. Certain
system disturbances may cause loss of synchronism between
a generator and rest of the utility system, or between
interconnected power systems of neighboring utilities. If
such a loss of synchronism occurs, it is imperative that the
generator or system areas operating asynchronously are
separated immediately to avoid widespread outages and
equipment damage. Here it is described to distinguish
between power swing and real fault. It is also discussed
recent enhancements in the design of out of step tripping
and blocking protection functions that improve the security
and reliability of the power system. In addition to that the
behavior of distance relay element during power swing and
during fault is simulated using MATLAB and SIMULINK
simulations.
Keywords: Power Swing, Out of Step, Out of step tripping,
Out of Step blocking, R-dot, Swing Center Voltage
I. INTRODUCTION
Power systems in the India have experienced a number of
large disturbances. These major system disturbances also
impacted several million customers in India. All of these
disturbances caused considerable loss of generation and
loads and had a tremendous impact on customers and the
economy in general. Typically, these disturbances happen
when the power systems are heavily loaded and a number of
multiple outages occur within a short period of time, causing
power oscillations between neighboring utility systems, low
network voltages, and consequent voltage instability or
angular instability.[1-2]
Power system faults, line switching, generator
disconnection, and the loss or application of large blocks of
load result in sudden changes to electrical power, whereas
the mechanical power input to generators remains relatively
constant. These system disturbances cause oscillations in
machine rotor angles and can result in severe power flow
swings. Depending on the severity of the disturbance and
the actions of power system controls, the system may
remain stable and return to a new equilibrium state
experiencing what is referred to as a stable power swing.
Severe system disturbances, on the other hand, could cause
large separation of generator rotor angles, large swings of
power flows, large fluctuations of voltages and currents, and
eventual loss of synchronism between groups of generators
or between neighboring utility systems. Large power
swings, stable or unstable, can cause unwanted relay
operations at different network locations, which can
aggravate further the power-system disturbance and possibly
lead to cascading outages and power blackouts.
The main reason for the system blackout is wrong operation
of some protective relays. Therefore in this paper various
power swing detection methods are simulate to study their
ability to detect power swing and distinguish stable and
unstable power swings.
II. POWER SWING DETECTION METHODS
Fast detection of power swings is of interest in distance
protection of transmission lines. In distance protection, the
main goal is to prevent high speed distance protection to
operate during stable swing. This requires the detection of a
power swing to be done within mili-seconds. The possibility
to accurately determine the swing frequency and damping
within such a short time is naturally limited.
The task of a power swing detector in a distance protection
relay is to prevent unintended operation of the relay during a
stable power swing. Ideally we would also like the detector
to trip the relay when an unstable power swung is detected.
Depending on when the unstable swing is detected we can
choose to trip before or after a pole slip occurred. Normally,
it is desirable to trip before the out of step condition occurs.
However the unstable swing is detected when the swinging
machines are close to phase opposition it might be
advantageous to trip after the pole slip has occurred. The
reason is that the wear and tear of the circuit breaker will be
reduced when it does not have to operate at its maximum
rating.
A 4 machine 10 bus system [3-4] for testing of the power
swing detection methods is considered here. This model has
been chosen for a comparative evaluation of various
methods of power swing detection. The single line diagram
of the system is shown in the fig 1.
Fig. 1: Four machine ten bus systems
In this paper, a comparative evaluation of the various
methods of power swing detection, namely the blinder
schemes, Rdot method and the rate of change of SCV have
been carried out.
Power Swing Phenomena and Comparative Study of Its Detection
on Transmission Line
V.J.Upadhyay1
Ashit Pandya2
1
Associate. Professor 2
Head of Department
1,2
Department of Electrical Engineering
1
Government Eng. College, Dahod, Gujarat, India
2
Government Polytechnic-Rajkot, Gujarat, India
2. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1193
The system is simulated using MATLAB/Simulink. The
simulation model for synchronous machines is taken from
ref [6].
III. CONVENTIONAL RATE OF CHANGE OF
IMPEDANCE METHODS
A. Mho relay
Mho relay is the classical distance relay[5]. This relay gives
a trip signal when power swing enters the mho
characteristics. The relay is often set to a sensitivity of 120o
load angle since return to stable operation is usually
unattainable when angle further increases. As the tripping in
these relays occur before change in voltage angle to 1800
hence stability studies are not required for setting of these
relays. It has the limitations of mal operating for recoverable
swings i.e. this relay works only with OOS tripping function
and not for power swing blocking (PSB) function.
The mho relay characteristics have been modeled using
equation (3.1). Here R and X are the swing impedances as
seen by the relay. R1 and X1 are the p.u. resistance and
reactance of a line. Fig 2 explains this clearly. The swing
locus entering the circular mho characteristics initiates the
switching action.
2
1
2
12
1
2
1
22
)()(
XR
XXRR (1)
The Centre of the mho characteristics is considered
coinciding with the Centre of the line characteristics fig.3
for the sake of simplicity. Also 100% of the line length is
considered for the sake of power swing detection.
Fig. 2: Mho characteristics
A. Blinder Scheme
1) Single Blinder Scheme
A single-blinder scheme [7] uses only one set of blinder
characteristics on either side of the system impedance.
When power swing occurs, the apparent impedance travels
across the impedance plane. A trip condition exists if the
impedance locus enters the outer load blinder unit. The
locus must enter from one side and leave from the other for
tripping to occur. Single blinder scheme is shown in Fig. 3
Equation of a straight line is given by y = mx + c, where c is
the y intercept and m is the slope of the line. In this case
both the blinders are considered parallel to the line
characteristics having slope X1 /R1,. The intercept c is
considered to be +X1 and –X1 for right and left blinders
respectively. With reference to fig 3 the OOS condition is
given when (X-c)/m<R and (X+c)/m>R. Additional
condition s satisfying the trip ping criteria are R>0 AND
R<R1 AND X>=0 AND X<=X1
.
Fig. 3: Single blinder scheme
2) Double Blinder Scheme:
The two-blinder scheme [2-7] shown in Figure 4 is based
on the same principle of measuring the time needed for an
impedance vector to travel a certain delta impedance. The
time measurement starts when the impedance vector crosses
the outer blinder (RRO) and stops when the inner blinder
(RRI) is crossed. If the measured time is above the
setting for delta time, a power swing situation is
detected. If the blinders are set in parallel to the line
impedance, then they are optimized for the delta impedance
measurement because the power swing impedance vectors
will normally enter the protection zones at an angle of
nearly 90 degrees to the line angle. Depending on certain
network conditions, this may not be always correct but it can
be assumed for simplification.
The single blinder algorithm has been modified to create a
double blinder scheme. If t1 and t2 are time of crossing of
inner and outer blinders by the power swing and R1 and R2
are the swing resistance during crossing of the blinders, the
rate of change of impedance is given by (R2-R1)/(t2-
t1).Various stability studies have been carried out to get a
suitable setting for the rate of change.
Fig.4.Double Blinder scheme
If an unstable swing is detected, the mho element can be
allowed to trip immediately (not recommended) or tripping
X1
X1/2
R1R1/2
CHARACTERISTICS OF
TRTRANSMISSION LINE
MHO
CHRACTERISICS
POWER SWING
LOCUS
3. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1194
can be delayed until the swing passes through thereby
minimizing over-voltages across the opened breaker.
To find the correct settings for the blinders is not always
simple and requires a sophisticated grid analysis In these
schemes the blinders are set parallel to the line elements.
IV. ADVANCED POWER SWING DETECTION
METHOD
The advent of digital technology has given relay design
engineers the ability to develop and implement new methods
for detecting power swings. A number of the new
techniques do not require user-entered settings, thus greatly
simplifying the application of power swing detection and
protection. Others still require study. Which can sometimes
be very extensive and time consuming?
A. Rdot SCHEME
Out-of-step tripping initiation on major EHV
interconnections sometimes is required before the voltage
at the electrical center reaches a minimum value. This
prevents severe voltage dips throughout the power system
with possible uncontrolled loss of loads and loss of
synchronism within sub-areas of utility network.[8]
Fig.5. Phase – plane Diagram illustrating the concept of R-
dot principle
The OST relay was augmented with the rate of change of
apparent resistance and it was termed the Rdot scheme. The
Rdot scheme aims at early tripping for non-recoverable
swings while avoiding tripping on recoverable swings. This
is achieved by using the phase-plane between the apparent
resistance R and the rate of change of resistance Rdot. The
tripping conditions in case of Rdot scheme is given by
equation (4.1)
1. Conventional OST relay : Yl = ( R – Rl ) ≤ 0
2. R-dot relay :
0)(2 11
dt
dR
TRRY
(2)
Where Y1 and Y2 are control outputs, R is the apparent
resistance measured by the relay and R1 and T1( slop of line )
are relay-setting parameters. The above characteristic of
the R-dot relay[8] can be best visualized in the R-Rdot
phase-plane shown in Figure 5. Y1, and Y2 then become
“switching lines” in the phase-plane and the Rdot relay
develops an output when the power-swing trajectory crosses a
“switching line” in the R-Rdot plane. For a conventional
OST relay without rate of change of apparent resistance
augmentation is just a vertical line in the R-Rdot plane offset
by the R1 relay setting parameter. Switching line Y2 is a
straight line having slope T1 in the R-Rdot plane. System
separation is initiated when output Y2 becomes negative.
For low separation rates (small Rdot : dR/dt) the
performance of the Rdot scheme is similar to the
conventional blinder relaying schemes. However, higher
separation rates dR/dt would cause a larger negative value of
Y2 and will initiate tripping much earlier. Hence the tripping
is faster in Rdot case than in the blinder schemes. The
amount of anticipation would be determined by T1.
B. Rate of Change of Swing center voltage (SVC)
Swing-center voltage (SCV)[8] is defined as the voltage
at the location of a two-source equivalent system where
the voltage value is zero when the angles between the two
sources are 1800
apart. When a two-source system loses
stability and goes into an OOS situation after some
disturbance, the angle difference of the two sources, δ(t),
will increase as a function of time. Figure 6 illustrates the
voltage phasor diagram of a general two-source system.
Fig. 6: Voltage phasor Diagram of a Two –
Source System
We can represent the SCV by Equation (4.2), assuming an
equal source magnitude, E.
2
cos
2
sin2)(
tt
tEtSCV
(4.2)
SCV (t) is the instantaneous SCV that is to be differentiated
from the SCV that we estimate locally. Equation (3) is a
typical amplitude-modulated sinusoidal waveform. The first
sine term is the base sinusoidal wave, or the carrier, with an
average frequency of ω + (1/2)( dδ / dt ). The second term
is the cosine amplitude modulation.
Fig. 7: Swing center voltage during OOS condition
The magnitude of swing center voltage changws between
zero and one per unit of system nominal voltage. With a
4. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1195
slip frequency of 5 Hz, the voltage magnitude is forced to
zero every 0.2 sec.
One popular approximation of SVC obtained through use of
locally available quantities is as follows[8].
cos
2
cos VsVsSCV
(3)
The absolute value of the SCV is at its maximum ( or one
) when the angle between the two sources is zero, and this
value is its minimum 9 or zero ) when the angle is 180
degrees. This property has been exploited so one can detect
a power swing by looking at the rate of change of the swing
center voltage. The time derivative of SCV then becomes
dt
dVs
dt
SCVd
2
sin
2
)( (4)
Equation 4 provides the relation between the rate of change
of the SCV and the two- machine system slip frequency
dδ/dt.
Fig. 8: SCV and its Rate of Change with Unity source
voltage magnitude.
The derivative of the SCV voltage is independent from the
network impedances. It is reaches its maximum when the
angle between the two machines is 1800
. When the angle
betweenthe two machines id zero, the rate of change of
SCV is also zero. The maximum value of the SCV „s
derivative occures, when the δ is 1800.
.
V. SIMULATION AND COMPARISION
By the implementation of algorithms for various types of
power swing detection schemes, stability studies have been
carried on the 4 machine 10 bus system [3-6]. A 3 phase
fault for a different duration has been simulated on bus 5
and 6 of the system. As it is required to study the speed and
accuracy of OOS condition, there is no tripping of lines
initiated on detection of OOS.
A. Mho Relay
Fig. 9: Power swing locus for Line 1-2-3 for a
Stable swing fault duration 0.25 second on bus 5
Fig. 10: Power swing locus for Line 7 for a Stable swing
fault duration 0.25 second bus 5
Fig. 11: Line Power swing locus for Line 8-9 for a unstable
swing fault duration 0.25 sec. on bus 5
Fig. 12: Line Power swing locus for Line 8-9 for unstable
swing fault duration 0.25 sec. on bus 5
-3 -2 -1 0 1 2 3 4 5
-6
-5
-4
-3
-2
-1
0
1
-6 -5 -4 -3 -2 -1 0 1 2 3 4
-10
-8
-6
-4
-2
0
2
5. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1196
B. Observations
1. This relay gives a trip signal when power swing enters
the mho characteristics.
2 As the tripping in these relays occur before change in
voltage angle to 1800
hence stability studies are not
required for setting of these relays.
3 It has the limitations of mal operating for recoverable
swings i.e. this relay works only with OOS tripping
function and not for power swing blocking (PSB)
function
C. Advantages
1 Simplest, no stability study required.
2 Tripping before power angel 180 deg.
3 No PSB function
1) Single Blinder Scheme
Fig.13. Power swing locus for Line 1-2-3 for a Stable
swing fault duration 0.2 sec. on bus 5
Fig. 14: Power swing locus for Line 1-2-3 for Stable wing
fault duration 0.25 sec on bus 5
Fig. 15: Power swing locus for Line 8-9 for a
Stable swing fault duration 0.2 sec. on bus 5
Fig. 16: Swing locus for line 8-9 for a 0.25 sec fault on bus
5
D. Observations
1 As such, this scheme cannot be used to block phase
distance relays from tripping for unstable power
swings because the relays will have tripped prior
to the scheme declaring an unstable condition.
2 The scheme can be used to prevent automatic reclosing
for a detected unstable power swing.
3 The single-blinder scheme delays OST until the swing
is well past the 180 degree position and is returning to
an in-phase condition.
4 The basic advantage of the single blinder scheme is its
use for load encroachment.
1) Double Blinder scheme:
Fig. 17: Power swing locus for Line 1-2-3 for a Stable
swing fault duration 0.2 sec. on bus 5
Fig. 18.Power swing locus for Line 1-2-3 for a Stable swing
fault duration 0.25 second on bus 5
-0.4 -0.2 0 0. 0. 0. 0. 1 1.
-1
-0.8
-0.6
-0.4
-0.2
0
0.
0.
0.
0.
6. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1197
Fig. 19: Power swing locus for Line 8-9 for a Stable swing
fault duration 0.25 second on bus 5
2) Observations:
1 This scheme is that it can mal-operate for recoverable
swings unless very careful selection of the relay
settings is made.
2 Stability studies have been carried out to determine
the rate of slip differentiating the stable swings form
unstable swings
3) Advantage
1 Can be used independent of distance zone
characteristics.
2 Carry out PSB and OOS protection.
A. R-dot Scheme
Fig.-20: Power swing locus for Line 1-2-3 for Stable swing
fault duration 0.2 sec. on bus 5
Fig. 21: Power swing locus for Line 8-9 for a unstable
swing fault duration 0.2 second bus 5
Fig.-21: Power swing locus for Line 1-2-3 for a unstable
swing fault duration 0.25 sec. On bus 5
Fig. 22: Power swing locus for Line 8-9 for a unstable
swing fault duration 0.25 sec. on bus 5
4) Observations:
1 For low separation rates, i.e. small Rdot,
performance of the algorithm is similar to that of
blinder scheme. But for higher separation rates,
Rdot is a large negative value causing earlier
separation hence anticipating probable instability.
Hence the tripping is faster in Rdot case than in
the blinder schemes.
B. Swing Center Voltage:
Fig. 23: SCV for all line for a Stable swing fault on bus 5
for 0.1 sec.
7. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1198
Fig. 24: SCV for all line for a Stable swing fault on bus 5
for 0.2 sec
Fig. 25: SCV for all line for a Unstable swing fault on bus 5
for 0.25 sec
5) Observations
1 Independent of network impedances hence setting of
relays not requires extensive stability studies.
2 Magnitude of SCV changes between 0 and 1 pu of the
system nominal voltage (E), regardless of system
impedance parameters
VI. RESULTS
Fault
Duration
Detection of OOS condition Stable (S) or
Unstable (US)
Mho
relay
Single
blinder
Double
Blinder
Rdot SCV
0.10 S S S S S
0.15 S S S US US
0.20 US US US US US
0.25 US US US US US
0.30 US US US US US
Table 1: Comparatives study of OOS detection for lines 1-
2-3 with fault on bus 5
Fau
lt
Dur
Swin
g
Freq.
(Hz)
Time taken to detect of OOS
condition after fault clearance (sec)
Mho
relay
Singl
e
Doub
le Rdo
t
SC
V
blinder
0.10 0.10 -- -- -- -- --
0.15 0.32 -- -- -- 0.94 1.21
0.20 0.52 -- -- -- 0.91 1.13
0.25 1.8 -- 0.85 0.85 0.87 0.95
0.30 3.55 0.43 0.49 0.49 0.49 0.54
Table 2: Comparatives study of OOS detection for lines 1-
2-3 with fault on bus 5
Table 3: Comparative study of OOS detection for lines 8-9
with fault on bus 5
Fault
Dur.
Swi
ng
Freq
.
(Hz)
Time taken to detect of OOS
condition after fault clearance (sec)
Mho
relay
Single
Doubl
e Rdo
t
S
C
Vblinder
0.10 0.10 -- -- -- -- --
0.15 0.22 -- -- -- 0.94
1.
14
0.20 0.34 -- -- -- 0.90
1.
02
0.25 0.53 -- 0.79 0.84 0.88
0.
88
0.30 3.85 0.36 0.47 0.46 0.45
0.
51
Table 4: Comparative study of OOS detection for lines 8-9
with fault on bus 5
VII. CONCLUSION
The paper draws a number of conclusions.
1 Simulation of various methods of OOS detection has
been carried on a four machine system using Matlab and
Simulink tools. A comparative evaluation of the these
different power swing detection methods has been
performed. It is observed that the response time if all
scheme is inversely proportional to the swing frequency.
So as system becomes more unstable, so response time
becomes faster. hence sever faults are detected in least
time
2 A single-blinder characteristic plus auxiliary logic can be
used for an OST function. It can be used to restrict
Fault
Dur.
Detection of OOS condition Stable (S)
or Unstable (US)
Mho
relay
Single
blinder
Doubl
e
Blinde
r
Rdot SCV
0.10 S S S US US
0.15 US US US US US
0.20 US US US US US
0.25 US US US US US
0.30 US US US US US
8. Power Swing Phenomena and Comparative Study of Its Detection on Transmission Line
(IJSRD/Vol. 1/Issue 5/2013/039)
All rights reserved by www.ijsrd.com 1199
tripping of the distance relay for loads outside of
the blinders. The single-blinder scheme cannot
distinguish between a fault and an OOS condition until
the fault has passed through the second blinder within a
given time. As such, this scheme cannot be used to block
phase distance relays from tripping for unstable power
swings because the relays will have tripped prior to
the scheme declaring an unstable condition. The
scheme can be used to prevent automatic reclosing for a
detected unstable power swing. In addition, the single-
blinder scheme delays OST until the swing is well past
the 180 degree position and is returning to an in-phase
condition. The basic advantage of the single blinder
scheme is its use for load encroachment.
3 The Rdot relays have been found to be operating in the
least time whereas the rate of change of SCV method has
operated for the most no of unstable cases.
4 The single and double blinder schemes have similar
characteristic but double blinder scheme have benefit of
selection of trip on the way in(TOWI) and trip on the
way out(TOWO),,hence preventing damage to the circuit
breakers. Limitations of this scheme are that it can mal-
operate for recoverable swings unless very careful
selection of the relay settings is made. Stability studies
have been carried out to determine the rate of slip
differentiating the stable swings form unstable swings.
5 The rate of change of SCV has a benefit that this method
is independent of system source and line impedances,
hence setting of relay becomes simpler as compare to
other method
REFERENCES
[1] E. W. Kimbark, Power System Stability, vol. 2,
John Wiley and Sons, Inc., NewYork, 1950.
[2] Demetrios Tziouvaras and Daqing Hou, "Out-
of-Step Protection Fundamentals and
Advancements", 30th Annual Western
Protective Relay Conference, October 21-23,
2003,
[3] Prabha Kundur, Power Stability and Control,
The EPRI Power System Engineering Series,
McGraw Hill Inc., 1994.
[4] K. R. Padiyar, “Power System Dynamics –
Stability and Control”, 2nd
edition, B.S.
Publications 2002.
[5] P.M. Anderson. “ Power System Protection “.
New York: IEEE Press, 1999
[6] Pradeep, K.N. Shubhanga, “Mannual fo r Multi-
machin e Transient Stability Program”, Dept of
Elect Engg, NITK Surathkal, Srinivasnagar,
Mangalore, India.
[7] J. Mooney and N. Fischer, “Application
guidelines for power swing detection on
transmission lines,” Schweitzer Engineering
Laboratories, Inc, 2005
[8] IEEE PSRC WG D6 “ power swing and out of
step considerations on transmission line “ June
2005
[9] C.W. Taylor, J.M. Haner, L.A. Hill, W.A.
Mittelstad and R.L. Cresap, “A New out of- Step
Relay with Rate of Change of Apparent Resistance
Augmentation” IEEE Transactions on Power
Apparatus and System, Vol. PAS- 102, No. 3,
March 1983