The document proposes a differential power-based technique to detect symmetrical faults during power swings. It uses an auto-regression method to predict voltage and current samples during swings. The difference between predicted and actual samples is used to calculate differential power, which is high for faults and low for swings. The method was tested on different systems and fault scenarios and could accurately identify faults during slow and fast swings.
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
Fuzzy-Logic-Controller-Based Fault Isolation in PWM VSI for Vector Controlled...iosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
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
Fuzzy-Logic-Controller-Based Fault Isolation in PWM VSI for Vector Controlled...iosrjce
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Closed Loop Non Linear Control of Shunt Hybrid Power Filter for Harmonics Mit...IAES-IJPEDS
In recent years, the amount of non-linear loads has increased considerably since there were improvements in power electronic equipment (such as adjustable speed drives or converter ac-dc, ac-ac, dc-ac and dc-dc) in industrial sectors which cause deterioration of the quality of the electric power supply through distortion of supply voltage and supply current. This has led to improvement of many stringent needs regarding generation of harmonic current, which are found in IEEE519 and IEC61000 standards. This paper proposes a non-linear function based closed loop control strategy (without load current extraction) for three-phase Shunt Active Power Line Conditioner and LC passive filter to compensate harmonics, power factor improvement and enhance the dynamic performance of Shunt Hybrid Power Filter (SHPF). By using a PI controller the DC bus voltage of the Shunt Active Power Filter is maintained constant. Results obtained from simulation shows the performance of expected hybrid filter in transient and steady state operation . This indicates that the controller is able to compensate even under severe load current imbalances.
Extra high voltage long ac transmission linesShivagee Raj
From economical point of view designing of transmission line system is very important in the electricity supply system. Extra High Voltage Transmission Lines are best suited for transmission of bulk power.
Concurrent Detection and Classification of Faults in Matrix Converter using T...IAES-IJPEDS
This paper presents a fault diagnostic algorithm for detecting and locating open-circuit and short-circiut faults in switching components of matrix converters (MCs) which can be effectively used to drive a permanent magnet synchronous motor for research in critical applications. The proposed method is based on monitoring the voltages and currents of the switches. These measurements are used to evaluate the forward trans-conductance of each transistor for different values of switch voltages. These trans-conductance values are then compared to the nominal values. Under healthy conditions, the values obtained for the fault signal is less than the tolerable value. Under the open/short-circuit conditions, the fault signal exceeds the threshold, hence enables the matrix converter drive to detect and exactly identify the location of the faulty IGBT. The main advantages of this diagnostic method include fast detection and locating of the faulty IGBT, easiness of implementation and independency of the modulation strategy of the converter.
Matlab Simulink in Three-Phase Fault Analysis on Transmission linepamu17
When different types of fault occurs in power system then in the process of transmission line fault analysis, determination of bus
voltage and the rms line current are possible. While consulting with the power system the terms bus voltage and rms current of line are very important. In case of three phase power system mainly two faults occurs, three phase balance fault and unbalance fault on transmission line of power system, such as line to ground fault, double line to ground fault and double line fault. The transmission line fault analysis helps to select and develop a better for protection purpose[1]. For the protection of transmission line we place the circuit breakers and its rating is depends on triple line fault. The reason behind is that the triple line fault current is very high as compare to other fault current.
simulation in computer, the analysis of transmission line fault can be easily carried out. The main purpose of this paper is to study the general fault type which is Unbalance faults of transmission line in the power system. Also to perform the analysis and obtain the Result of various parameters (voltage, current, power etc.) from simulation on those types of fault Using MATLAB. A new
modeling framework for analysis and simulation of unbalance fault
in power system on IEEE 14 bus system is Procedure includes the frequency information in dynamical models and produces approximate nonlinear Models that are well adopted for analysis and simulation. The transformer model includes Saturation. The parameters have been obtained from practical or experimental measurement.
Conclusion:-
The aforementioned benefits are typically seen to increase transmission lines capacity. Benefits of TCSC are not subject only to newly built TCSC installation but they can also be achieved by upgrading existing series compensation on the thyristors controlled series compensation or only its part, thus considerably extended its influence and usefulness.
The Need for Enhanced Power System Modelling Techniques & Simulation Tools Power System Operation
The Need for Enhanced Power System Modelling Techniques & Simulation Tools The Need for Enhanced Power System Modelling Techniques The Need for Enhanced Power System Modelling Techniques & Simulation Tools The Need for Enhanced Power System Modelling Techniques & Simulation Tools & Simulation Tools
Power Quality Disturbaces Clasification And Automatic Detection Using Wavelet...IJERDJOURNAL
Abstract— In this paper a development method to detect and classify the several power quality problems using the discrete wavelet transformation and artificial neural networks combined. There are several other methods in use to detect the same problem like Hilbert transform, Gabor transform, Gabor-Wigner transform, S transform, and Hilbert-Haung transform. The method of using wavelet and ANN includes the development of voltage waveforms of sampling rate and number of cycles, and also large number of power quality events with help of MATLAB software. The wavelet transformation and ANN tools used to get required coefficients. The obtained events of power quality monitored in each step to classify the particular event. These steps of the paper lead towards the automatic real time monitoring, detection and classification of power signals
A High-Performance SPWM Controller for Three-Phase UPS Systems Operating Unde...ijiert bestjournal
The increased use of rectifiers in critical loads employed by the information technologies,and medical and military equipment mandate the design of uninterruptible power supplies (UPS) with high- quality outputs. The highly nonlinear currents drawn especially by high-power single-phase rectifier loads greatly distort the uninterruptible power supplies (UPS) outputs. The distorted uninterruptible power supplies (UPS) voltages cause generation of low dc voltage at the output of the rectifier loads,which causes high current flow,increased power losses,and possibly the malfunction of the critical load or the uninterruptible power supplies (UPS). As a result,different harmonics mitigating techniques have gained a lot of attention. The main objective of this project is to develop simulation of a high-performance Pulse Width Modulation (PWM) technique based AC-DC converter system operating under highly nonlinear loads using MATLAB/SIMULINK. Here,controlled Insulated-gate bipolar transistor (IGBT) based AC-DC converter is used to supply the load instead of Diode or Thyristor Bridge. The pulse width modulation method is quite effective in controlling the root mean square (RMS) magnitude of the AC-DC converter output voltages and shape of input current. This enables automatic harmonic compensation by Rectifier itself.
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.
Open-Switch Fault-Tolerant Control of a Grid-Side Converter in a Wind Power G...IJPEDS-IAES
A fault-tolerant technique of a grid-side converter (GSC) is a very important
task because the unbalanced grid power endangers the overall system. Since
the GSC is very sensitive to grid disturbance, the complete system needs to
be stopped suddenly once an open-switch fault occurs. To improve the
reliability of system, the continuous operation should be guaranteed. In this
paper, a redundant topology based fault-tolerant algorithm is proposed for a
GSC in a wind power generation system. The proposed scheme consists of
the fault detection and fault-tolerant algorithms. The fault detection
algorithm employs the durations of positive and negaitive cycles of threephase
grid currents as well as normalized root mean square (RMS) currents.
Once a fault is detected, the corresponding faulty phase is identified and
isolated to enable the fault-tolerant operation. The faulty phase is replaced by
redundant one rapidly to recover the original shape of the grid currents,
which ensures the continuity in operation. In contrast with the conventional
methods, the proposed fault detection and fault-tolerant algorithms work
effectively even in the presence of the open faults in multiple switches in the
GSC. Simulation results verify the effectiveness of the proposed fault
diagnosis and fault-tolerant control algorithms.
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.
Closed Loop Non Linear Control of Shunt Hybrid Power Filter for Harmonics Mit...IAES-IJPEDS
In recent years, the amount of non-linear loads has increased considerably since there were improvements in power electronic equipment (such as adjustable speed drives or converter ac-dc, ac-ac, dc-ac and dc-dc) in industrial sectors which cause deterioration of the quality of the electric power supply through distortion of supply voltage and supply current. This has led to improvement of many stringent needs regarding generation of harmonic current, which are found in IEEE519 and IEC61000 standards. This paper proposes a non-linear function based closed loop control strategy (without load current extraction) for three-phase Shunt Active Power Line Conditioner and LC passive filter to compensate harmonics, power factor improvement and enhance the dynamic performance of Shunt Hybrid Power Filter (SHPF). By using a PI controller the DC bus voltage of the Shunt Active Power Filter is maintained constant. Results obtained from simulation shows the performance of expected hybrid filter in transient and steady state operation . This indicates that the controller is able to compensate even under severe load current imbalances.
Extra high voltage long ac transmission linesShivagee Raj
From economical point of view designing of transmission line system is very important in the electricity supply system. Extra High Voltage Transmission Lines are best suited for transmission of bulk power.
Concurrent Detection and Classification of Faults in Matrix Converter using T...IAES-IJPEDS
This paper presents a fault diagnostic algorithm for detecting and locating open-circuit and short-circiut faults in switching components of matrix converters (MCs) which can be effectively used to drive a permanent magnet synchronous motor for research in critical applications. The proposed method is based on monitoring the voltages and currents of the switches. These measurements are used to evaluate the forward trans-conductance of each transistor for different values of switch voltages. These trans-conductance values are then compared to the nominal values. Under healthy conditions, the values obtained for the fault signal is less than the tolerable value. Under the open/short-circuit conditions, the fault signal exceeds the threshold, hence enables the matrix converter drive to detect and exactly identify the location of the faulty IGBT. The main advantages of this diagnostic method include fast detection and locating of the faulty IGBT, easiness of implementation and independency of the modulation strategy of the converter.
Matlab Simulink in Three-Phase Fault Analysis on Transmission linepamu17
When different types of fault occurs in power system then in the process of transmission line fault analysis, determination of bus
voltage and the rms line current are possible. While consulting with the power system the terms bus voltage and rms current of line are very important. In case of three phase power system mainly two faults occurs, three phase balance fault and unbalance fault on transmission line of power system, such as line to ground fault, double line to ground fault and double line fault. The transmission line fault analysis helps to select and develop a better for protection purpose[1]. For the protection of transmission line we place the circuit breakers and its rating is depends on triple line fault. The reason behind is that the triple line fault current is very high as compare to other fault current.
simulation in computer, the analysis of transmission line fault can be easily carried out. The main purpose of this paper is to study the general fault type which is Unbalance faults of transmission line in the power system. Also to perform the analysis and obtain the Result of various parameters (voltage, current, power etc.) from simulation on those types of fault Using MATLAB. A new
modeling framework for analysis and simulation of unbalance fault
in power system on IEEE 14 bus system is Procedure includes the frequency information in dynamical models and produces approximate nonlinear Models that are well adopted for analysis and simulation. The transformer model includes Saturation. The parameters have been obtained from practical or experimental measurement.
Conclusion:-
The aforementioned benefits are typically seen to increase transmission lines capacity. Benefits of TCSC are not subject only to newly built TCSC installation but they can also be achieved by upgrading existing series compensation on the thyristors controlled series compensation or only its part, thus considerably extended its influence and usefulness.
The Need for Enhanced Power System Modelling Techniques & Simulation Tools Power System Operation
The Need for Enhanced Power System Modelling Techniques & Simulation Tools The Need for Enhanced Power System Modelling Techniques The Need for Enhanced Power System Modelling Techniques & Simulation Tools The Need for Enhanced Power System Modelling Techniques & Simulation Tools & Simulation Tools
Power Quality Disturbaces Clasification And Automatic Detection Using Wavelet...IJERDJOURNAL
Abstract— In this paper a development method to detect and classify the several power quality problems using the discrete wavelet transformation and artificial neural networks combined. There are several other methods in use to detect the same problem like Hilbert transform, Gabor transform, Gabor-Wigner transform, S transform, and Hilbert-Haung transform. The method of using wavelet and ANN includes the development of voltage waveforms of sampling rate and number of cycles, and also large number of power quality events with help of MATLAB software. The wavelet transformation and ANN tools used to get required coefficients. The obtained events of power quality monitored in each step to classify the particular event. These steps of the paper lead towards the automatic real time monitoring, detection and classification of power signals
A High-Performance SPWM Controller for Three-Phase UPS Systems Operating Unde...ijiert bestjournal
The increased use of rectifiers in critical loads employed by the information technologies,and medical and military equipment mandate the design of uninterruptible power supplies (UPS) with high- quality outputs. The highly nonlinear currents drawn especially by high-power single-phase rectifier loads greatly distort the uninterruptible power supplies (UPS) outputs. The distorted uninterruptible power supplies (UPS) voltages cause generation of low dc voltage at the output of the rectifier loads,which causes high current flow,increased power losses,and possibly the malfunction of the critical load or the uninterruptible power supplies (UPS). As a result,different harmonics mitigating techniques have gained a lot of attention. The main objective of this project is to develop simulation of a high-performance Pulse Width Modulation (PWM) technique based AC-DC converter system operating under highly nonlinear loads using MATLAB/SIMULINK. Here,controlled Insulated-gate bipolar transistor (IGBT) based AC-DC converter is used to supply the load instead of Diode or Thyristor Bridge. The pulse width modulation method is quite effective in controlling the root mean square (RMS) magnitude of the AC-DC converter output voltages and shape of input current. This enables automatic harmonic compensation by Rectifier itself.
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.
Open-Switch Fault-Tolerant Control of a Grid-Side Converter in a Wind Power G...IJPEDS-IAES
A fault-tolerant technique of a grid-side converter (GSC) is a very important
task because the unbalanced grid power endangers the overall system. Since
the GSC is very sensitive to grid disturbance, the complete system needs to
be stopped suddenly once an open-switch fault occurs. To improve the
reliability of system, the continuous operation should be guaranteed. In this
paper, a redundant topology based fault-tolerant algorithm is proposed for a
GSC in a wind power generation system. The proposed scheme consists of
the fault detection and fault-tolerant algorithms. The fault detection
algorithm employs the durations of positive and negaitive cycles of threephase
grid currents as well as normalized root mean square (RMS) currents.
Once a fault is detected, the corresponding faulty phase is identified and
isolated to enable the fault-tolerant operation. The faulty phase is replaced by
redundant one rapidly to recover the original shape of the grid currents,
which ensures the continuity in operation. In contrast with the conventional
methods, the proposed fault detection and fault-tolerant algorithms work
effectively even in the presence of the open faults in multiple switches in the
GSC. Simulation results verify the effectiveness of the proposed fault
diagnosis and fault-tolerant control algorithms.
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.
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.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
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/
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
3. ABSTRACT
• If a fault occurs during a power swing, it should be detected
and the unblocking function should be invoked to clear the
fault as soon as possible.
• Distance relays are getting blocked during power swing to
ensure reliability of the power system.
• Due to the symmetric nature of signals during the power
swing, symmetrical faults are difficult to be detected.
• In this paper, a differential power-based fault detection
technique is proposed for the detection of symmetrical faults
during power swings.
4. Cont…
• The differential power is calculated from the difference in
predicted and actual samples of voltage and current.
• The predicted voltage and current samples are obtained
using the auto regression technique.
• The proposed method is tested for different fault conditions
and the results are compared with the available method.
• The proposed method is found to identify symmetrical faults
accurately during slow and fast power swings for different
power systems.
5. Literature survey
• Power Swing which is basically caused by the large disturbances in
the power system which if not blocked could cause wrong operation
of the distance relay and can generates wrong or undesired tripping
of the transmission line circuit breaker.
• To prevent unwanted distance or other relay operation during a
Power Swing, we did fundamental studies of traditional and
advanced detection and prevention methods.
• However, many studies have shown that undesirable zone 3
distance relay operations have initiated tripping which lead to
cascading events and finally wide-area voltage collapse (Jonsson
and Daadler, 2003; Kim et al, 2005; Jin and Sindhu, 2008 ; Lim et al,
2008).
6. Cont…
• To improve reliability of relay operation, adaptive scheme for
distance protection has been introduced by many researches
(Horowitz, Phadke and Thorpe, 1988, Thorpe et al, 1988: Jonsson
and Daadler, 2003; Kim, Heo and Aggarwal, 2005; Lim et al, 2008).
• In adaptive distance protection relaying, an important aspect to be
considered is developing an indicator that can differentiate between
faults and power swings.
• The objective is to permit the trip signals during faults and block the
trip signals during other events.
• My enhancement to the topic is to clear or rectify the condition using
The Fault Mitigation Technique.
7. LITERATURE REVIEW PAPERS
Detection of Symmetrical Faults by Distance Relays During Power
Swings.
(IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 25, NO. 1, JANUARY 2010)
• To maintain security of distance relays, power swing blocking is
necessary to prevent unintended operation under power swings.
• This paper presents a new method for detecting a symmetrical fault during
a power swing, based on extracting components of the current waveform
using the Prony method.
• The merit of the proposed method was demonstrated by simulating
various cases including solid faults and arc fault on a typical power
system.
• The ease of implementation as well as accuracy and high speed of fault
detection are important advantages of the proposed method.
8. A Novel Approach to Detect Symmetrical
Faults Occurring During Power Swings by
Using Frequency Components of Instantaneous
Three-Phase Active Power
(IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 3, JULY 2012)
• Based on the damping frequency component of 50 (or 60) Hz created on
instantaneous three-phase active power profile after inception of a
symmetrical fault, the proposed method will be able to detect the fault in
less than one power cycle.
• This detection method can be readily implemented, and is immune to the
power swing slip frequency, fault inception time, and fault location.
• The proposed method has several advantages that are superior to the
existing methods. First, since it requires only three-phase active power,
which can be simply calculated by production of instantaneous voltage
and current, and FFT, which is coded in all digital relays, the new method
can be readily implemented. Second, the new method is very fast.
9. Fast Distance Relay Scheme for Detecting
Symmetrical Fault During Power Swing
(IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 25, NO. 4, OCTOBER 2010)
• The paper provides a fast detection scheme for symmetrical fault during
power swing for distance relay, which is based on extracting the high-
frequency component energy of forward and backward traveling waves
induced by faults.
• The multi resolution analysis based on wavelet transform has the ability to
decompose the analyzed signals into different frequency bands. The
selection of mother wavelet and the number of levels of wavelet transform
are carefully studied.
• The fault can be identified by feature extracting from the d1 component of
Daubechies-8 (Db8) wavelet transform.
• This proposed method can be used for distance relay operation blocking
or monitoring.
10. A Classification Approach Using Support Vector
Machines to Prevent Distance Relay Mal-operation
Under Power Swing and Voltage Instability
(IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 3, JULY 2012)
• Distance relays, in the power transmission systems, are susceptible to the mal-
operation under certain system events, such as power swings and voltage
instability
• The proposed scheme segregates the power system events into faults, power
swings, and voltage instability.
• This paper also proposes a new index, called the relay ranking index, for
identifying the relays most vulnerable to the mal-operation due to power
swings and voltage instability.
• The scheme effectively discriminates the dynamic encroachment events and
differentiates the system events into power swings and voltage instability by
utilizing the transmission- line reactive power loss as a key indicator for the
voltage-unstable situation.
11. Mitigating the Impacts of CCVT Subsidence
Transients on the Distance Relay
(IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 2, APRIL 2012)
• The paper presents a comprehensive time-domain model of the
coupling capacitor voltage transformer (CCVT) to investigate the effect
of CCVT subsidence transients on the distance relay.
• The studies show that voltage-zero subsidence transients can
adversely impact the performance of the distance relay and result in
the overreach problem.
• The method is based on improving the degree of accuracy of the
voltage Phasor estimation during the CCVT subsidence transients.
• The proposed method is not affected by harmonics and high-
frequency transient distortions of the voltage, and prevents the relay
overreach problem.
12. Review of existing methods
• In a power system disturbance-like faults, generator
disconnection and change in the large block of
loads are the main reasons for power swing.
• Large variations in voltage and current causes
undesired tripping of distance relay which may lead
to subsequent line outages.
• The power swing blocking (PSB) function is used to
prevent mis-operation of distance relays during
swing.
13. • If a fault occurs during the power swing, it should
be detected and suppressed.
• Conventional fault detection techniques may fail to
distinguish fault during the power swing.
• Symmetric nature of phase voltages and currents
during the swing makes this task tedious.
14. PROPOSED METHOD
• Full-cycle sample points of voltage and current
are predicted using auto regression technique
for any phase.
• It models the nth value of a variable as a
function of previous values, where k is the order
of the model.
• The accuracy of the prediction technique
improves with a higher value of k.
15. PHASE 1 - CASE STUDY
• The method is tested for various fault conditions
during the power swing for a 400-kV double-
circuit transmission system (i)
• A 230-kV WSCC 3-machine, a nine-bus system
(ii)
• Simulation and analysis are going to be done
through PSCAD/EMTDC
17. ANALYSIS WITH AUTO REGRESSION
PROGRAMME
• Auto regression is a special technique for
regression analysis.
• The technique models nth values of the system
as a function of K previous values.
• Higher values of K improves the system
prediction accuracy.
18. Cont…
• The expression for the Kth order auto regression model
is
• where a1,a2….aK are the auto regression coefficients
and i’s are the samples of the variable.
• The calculation of coefficients are done by considering
the P available samples of the system.
19. Cont…
• matrix form of the system can be written as
• It can be further written as
• The future sample points are calculated using
available samples and [A]
20. Cont…
• The expression for obtaining future samples
(next q samples) is
• The accuracy of prediction decreases with
length of q.
• The accuracy of the technique depends on the
selection of k, p, q.
21. Cont…
• The coefficients of the auto regression technique are
calculated using previous samples of a variable and
these samples gives a clear picture of the future
disturbances and system oscillations.
• The difference between the predicted and actual values
of the variable is found to be negligible when there is no
external disturbance with the selected system.
22. Cont…
• The differential components of voltage and
current at any sampling instant of time are
calculated as follows:
23. Cont…
• The rms values of differential voltage and
current are calculated over a period of one cycle
Where N is the number of samples per cycle
25. RESULTS FOR THE DOUBLE-CIRCUIT LINE
• The system is simulated using PSCAD/EMTDC
software with a distributed transmission-line model.
• A three-phase fault is created in Line-2 at point F at
0.5 s, which is cleared after 0.1 s by the opening of
breakers B3 and B4. As a result, the distance relay R1
in line-1 experiences a power swing.
• Any fault in line-1 during the swing has to be detected
by relay R1.
30. Inference
• The difference in the actual and predicted samples of the
voltage and current during the power swing followed by a
three-phase fault at 3.65 s are shown.
• The wave forms obtained are clearly showing the
predicted and actual samples of voltage, current and
power during the swing and fault.
• Difference in predicted and actual samples of voltage
and current is less during the power swing and high for
the fault period.
31. • The differential power can be obtained directly from the
current – voltage waveforms.
• The magnitude of ΔP is negligible for the power swing
and high for the fault period.
• The algorithm identifies the fault if the magnitude
exceeds the threshold value of ΔP.
• The selection of threshold value is much important to get
a more accurate fault detection.
• The threshold value should be greater than the
maximum differential power during the swing condition.
32. CONCLUSION
• Detection of symmetrical fault during power swing is actually a
threat to power system protection.
• The base paper is hereby proposing an auto-regression based
study of symmetrical fault components during the swing period.
• But mitigating a fault is much beneficial than making a tripping with
the CBs.
• The thesis is thus proposing a fault mitigation scheme to assure an
improved reliability with the power system.