The issue of voltage instability is becoming a matter of concern throughout the world. It is of
absolute importance to maintain the stability of the power system or it would lead to a condition of total
collapse of the system and ultimately blackout of the whole network. This paper analyses the performance of
line voltage stability indices, Fast Voltage Stability index (FVSI), Line index (LQP), Reactive Power Index
(VQI) and line Stability Index (LMN). These indices are used to identify the most critical line and bus of the
system. Under a condition of single line outage a TCSC is installed at the most critical line and its effect has
been observed. An IEEE 14 bus system is used for simulation purpose.
Efficacy of Facts in Power Oscillation Damping and Renewable IntegrationIOSRJEEE
This document summarizes research on using flexible AC transmission system (FACTS) devices to improve power oscillation damping and facilitate renewable energy integration. It discusses how power oscillations can lead to instability if not controlled and how FACTS devices like STATCOM and SVC can enhance stability. It presents simulations of the IEEE 14-bus system that demonstrate improved damping from these controllers. Eigenvalue analysis shows STATCOM shifts modes further into the stable region than SVC. Both STATCOM and SVC integration helps renewable sources by mitigating power quality issues to allow more distributed generation on the grid.
This document summarizes research into improving transient stability in power transmission systems using a Static VAR Compensator (SVC) with a hybrid PI-Fuzzy Logic controller. It begins with an introduction to Flexible AC Transmission Systems (FACTS) and the role of SVC devices in voltage control and reactive power compensation. It then describes modeling an SVC and the operating principles of conventional PI control. The limitations of PI control for nonlinear systems are discussed. The document proposes a hybrid PI-Fuzzy Logic controller to combine the advantages of both. Simulation results using MATLAB on a 2-machine 3-bus test system show the hybrid controller improves performance during disturbances over PI or Fuzzy Logic control alone.
This paper presents a method to improve transient stability and damping of low frequency oscillations in a multi-machine power system using adaptive neuro-fuzzy control of FACTS devices. A Simulink model of a three generator power system equipped with a UPFC is developed. Simulation results show that a UPFC controlled using an adaptive neuro-fuzzy inference system controller more effectively improves transient stability and damps power oscillations compared to using SSSC. The neuro-fuzzy controller is trained using a hybrid learning algorithm to tune its parameters online based on generator speed deviation and acceleration as inputs.
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.
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.
Power Flow Control in Power System Using FACT Device Thyristor Controlled Ser...IOSR Journals
This document summarizes a study on using Flexible AC Transmission System (FACTS) devices for power flow control in a power system. Specifically, it models and simulates the use of Thyristor Controlled Series Capacitor (TCSC) and Static VAR Compensator (SVC) in a two-area, four-machine 11-bus test system using MATLAB/Simulink. TCSC is installed between buses 9 and 10 to reduce line reactance and improve power flow. SVC is installed at bus 9 for voltage control. Simulation results show that TCSC and SVC effectively control active and reactive power flows and bus voltages in the system.
Transient stability in power system is vital to be addressed due to large disturbances that could damage the system such as load changes and voltage increases. This paper presents a multi-machine transient stability using the Static Synchronous Series Compensator (SSSC). SSSC is a device that is connected in series with the power transmission line and produces controllable voltage which contribute to a better performance in the power system stability. As a result, this research has observed a comparison of the synchronization of a three-phase system during single-phase faults before and after installing the SSSC device. In addition, this research investigates the ability of three different types of controllers i.e. Proportional Integral (PI), Proportional Integral Derivation (PID), and Generic controllers to be added to the SSSC improve the transient stability as it cannot operate by itself. This is because the improvement is too small and not able to achieve the desired output. The task presented is to improve the synchronization of the system and time taken for the voltage to stabilize due to the fault. The simulation result shows that the SSSC with an additional controller can improve the stability of a multi-machine power system in a single phase fault.
1) The document compares the effectiveness of TCSC (Thyristor Controlled Series Capacitor) and SSSC (Static Synchronous Series Compensator) in damping sub-synchronous oscillations in power systems.
2) It describes the control structures of TCSC and SSSC, which include a PI controller and supplementary sub-synchronous damping controller (SSDC) that takes the rotor speed deviation as input.
3) Simulation results on the IEEE second benchmark model show that SSSC has superior ability to damp sub-synchronous oscillations compared to TCSC when subjected to disturbances like a change in input mechanical power or disconnection of a transmission line.
Efficacy of Facts in Power Oscillation Damping and Renewable IntegrationIOSRJEEE
This document summarizes research on using flexible AC transmission system (FACTS) devices to improve power oscillation damping and facilitate renewable energy integration. It discusses how power oscillations can lead to instability if not controlled and how FACTS devices like STATCOM and SVC can enhance stability. It presents simulations of the IEEE 14-bus system that demonstrate improved damping from these controllers. Eigenvalue analysis shows STATCOM shifts modes further into the stable region than SVC. Both STATCOM and SVC integration helps renewable sources by mitigating power quality issues to allow more distributed generation on the grid.
This document summarizes research into improving transient stability in power transmission systems using a Static VAR Compensator (SVC) with a hybrid PI-Fuzzy Logic controller. It begins with an introduction to Flexible AC Transmission Systems (FACTS) and the role of SVC devices in voltage control and reactive power compensation. It then describes modeling an SVC and the operating principles of conventional PI control. The limitations of PI control for nonlinear systems are discussed. The document proposes a hybrid PI-Fuzzy Logic controller to combine the advantages of both. Simulation results using MATLAB on a 2-machine 3-bus test system show the hybrid controller improves performance during disturbances over PI or Fuzzy Logic control alone.
This paper presents a method to improve transient stability and damping of low frequency oscillations in a multi-machine power system using adaptive neuro-fuzzy control of FACTS devices. A Simulink model of a three generator power system equipped with a UPFC is developed. Simulation results show that a UPFC controlled using an adaptive neuro-fuzzy inference system controller more effectively improves transient stability and damps power oscillations compared to using SSSC. The neuro-fuzzy controller is trained using a hybrid learning algorithm to tune its parameters online based on generator speed deviation and acceleration as inputs.
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.
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.
Power Flow Control in Power System Using FACT Device Thyristor Controlled Ser...IOSR Journals
This document summarizes a study on using Flexible AC Transmission System (FACTS) devices for power flow control in a power system. Specifically, it models and simulates the use of Thyristor Controlled Series Capacitor (TCSC) and Static VAR Compensator (SVC) in a two-area, four-machine 11-bus test system using MATLAB/Simulink. TCSC is installed between buses 9 and 10 to reduce line reactance and improve power flow. SVC is installed at bus 9 for voltage control. Simulation results show that TCSC and SVC effectively control active and reactive power flows and bus voltages in the system.
Transient stability in power system is vital to be addressed due to large disturbances that could damage the system such as load changes and voltage increases. This paper presents a multi-machine transient stability using the Static Synchronous Series Compensator (SSSC). SSSC is a device that is connected in series with the power transmission line and produces controllable voltage which contribute to a better performance in the power system stability. As a result, this research has observed a comparison of the synchronization of a three-phase system during single-phase faults before and after installing the SSSC device. In addition, this research investigates the ability of three different types of controllers i.e. Proportional Integral (PI), Proportional Integral Derivation (PID), and Generic controllers to be added to the SSSC improve the transient stability as it cannot operate by itself. This is because the improvement is too small and not able to achieve the desired output. The task presented is to improve the synchronization of the system and time taken for the voltage to stabilize due to the fault. The simulation result shows that the SSSC with an additional controller can improve the stability of a multi-machine power system in a single phase fault.
1) The document compares the effectiveness of TCSC (Thyristor Controlled Series Capacitor) and SSSC (Static Synchronous Series Compensator) in damping sub-synchronous oscillations in power systems.
2) It describes the control structures of TCSC and SSSC, which include a PI controller and supplementary sub-synchronous damping controller (SSDC) that takes the rotor speed deviation as input.
3) Simulation results on the IEEE second benchmark model show that SSSC has superior ability to damp sub-synchronous oscillations compared to TCSC when subjected to disturbances like a change in input mechanical power or disconnection of a transmission line.
The document provides information on power system stability and transient stability studies. It introduces key concepts such as stability, transient stability studies, rotor dynamics, the swing equation, and the power-angle equation. The swing equation describes the acceleration of a generator's rotor and relates the mechanical input power to the electrical output power. The power-angle equation models the relationship between generator output power and the power angle during transient stability studies.
Transient Stability Assessment and Enhancement in Power SystemIJMER
This document discusses transient stability assessment and enhancement in power systems. It first introduces transient stability and its importance. It then describes using PSAT software to analyze the IEEE 39-bus test system and calculate critical clearing times (CCTs) for different faults to assess stability. An artificial neural network is trained to predict CCTs at different operating points. Finally, particle swarm optimization is used to find the optimal placement of a thyristor controlled series capacitor to enhance stability by minimizing real power losses, increasing several CCTs above 0.1 seconds.
This document discusses various topics related to power system stability including:
1. It defines power system stability as the ability of a system to regain equilibrium after a disturbance. It classifies stability into rotor angle stability, voltage stability, and frequency stability.
2. Rotor angle stability depends on the balance between electromagnetic and mechanical torque on generators. Voltage stability refers to maintaining steady voltages after a disturbance.
3. It derives and explains the swing equation, which describes the relative motion of a generator rotor during disturbances. It provides the swing equation both with and without damper torque.
4. It discusses single machine infinite bus systems and provides the equivalent circuit diagram. Small-signal angle stability refers to the ability of a system
Evolve the Controller for Static Synchronous Series Compensator Based on Cont...IJPEDS-IAES
Real and Reactive power flow in an alternating current transmission line can be independently controlled by connecting, to the transmission line, a series- compensating voltage, which is variable in magnitude and phase angle. The Static Synchronous Series Compensator (SSSC), a solid-state voltage source inverter (VSC) coupled with a transformer, is connected in series with a transmission line. An SSSC injects an almost sinusoidal voltage, of variable magnitude, in series with a transmission line. This injected voltage is almost in quadrature with the line current, thereby emulating an inductive or a capacitive reactance in series with the transmission line. This emulated variable reactance, inserted by the injected voltage source, influences the electric power flow in the transmission line. In this report, an attempt is made to evolve the model of SSSC and VSC with preliminary studies for the controller design.
The Impact of Line Resistance on the Performance of Controllable Series Compe...Editor Jacotech
In recent years controllable FACTS devices are increasingly
integrated into the transmission system. FACTS devices that
provide series control such as Controllable Series Compensator
(CSC) has significant effect on the voltage stability of Electric
Power system. In this work impact of line resistance on the
performance of CSC in a single-load infinitive-bus (SLIB)
model is investigated. The proposed framework is applied to
SLIB model and obtained results demonstrates that line
resistance has considerable effect on voltage stability limits and
performance of CSC.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
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.
This paper proposes using a genetic algorithm to determine the optimal location of a thyristor controlled series capacitor (TCSC) device to enhance available transfer capability (ATC) between source and sink areas in a deregulated power system. The paper simulates placing a TCSC in the IEEE 14-bus test system and uses repeated power flow calculations to compute the ATC with and without the TCSC to determine how much it can enhance transmission capacity.
Transient stability analysis and enhancement of ieee 9 bus system ecij
System stability study is the important parameter of economic, reliable and secure power system planning and operation. Power system studies are important during the planning and conceptual design stages of the project as well as during the operating life of the plant periodically. This paper presents the power system stability analysis for IEEE- 9 bus test system. The fault is created on different busses and transient stability is analyzedfor different load and generation conditions. The critical clearing time (CCT) is calculated by
using time domain classical extended equal area criterion method. The system frequency and voltage variation is observed for different fault locations and CCT. The IEEE-9 bus test system is simulated and stability is analyzed on ETAP software
This document provides an overview of power system stability analysis. It defines power system stability as the ability of a system to maintain equilibrium during normal operation and regain equilibrium after disturbances. It discusses different types of stability including rotor angle stability and voltage stability. Key factors that influence stability like operating conditions, faults, and clearing times are also summarized. Methods for enhancing stability such as high-speed fault clearing and controlled load shedding are briefly mentioned. Models for analyzing stability like the swing equation and equal area criterion are defined in less than 3 sentences.
Comparison of Shunt Facts Devices for the Improvement of Transient Stability ...IJSRD
This paper presents, the performance of STATCOM placed at midpoint of the two machine power system and compared with the performance of SVC. The comparison of various results found for the different type of faults (single line, double line & three phase fault) occur in long transmission line, and their removal by using shunt FACTS devices is analysed. Computer simulation results under a severe disturbance condition (three phase fault) for different fault clearing times, and different line lengths are analyzed. Both controllers are implemented using MATLAB/SIMULINK. Simulation results shows that the STATCOM with conventional PI controller installed with two machine three bus systems provides better damping oscillation characteristics in rotor angle as compared to two machine power system installed with SVC. The transient stability of two machine system installed with STATCOM has been improved considerably and post settling time of the system after facing disturbance is also improved.
This document discusses using a static var compensator (SVC) to improve power system stability in a long transmission line system. It describes how SVCs can effectively control dynamic performance and regulate system voltage. The document presents a MATLAB model of a two-area power system with an SVC installed. Simulation results show that the SVC improves transient stability by reducing rotor angle differences and regulating real and reactive power flows. In conclusion, properly modeling SVC controllers can provide benefits for power system stability studies.
The document analyzes and compares the impact of different shunt compensation devices (shunt capacitor, synchronous phase modifier (SPM), and static VAR compensator (SVC)) on voltage stability enhancement. It identifies the most critical contingency using indices like P-V curves, L-index, and fast voltage stability index (FVSI) for the IEEE 9-bus, 30-bus, and 118-bus test systems. The optimal location and size of the shunt compensator is determined by placing a fictitious generator at the weakest bus. Simulation results show that all three devices can improve voltage stability against load variations, with SPM having slightly higher losses than the other options.
Sensitivity based optimal location of tcsc for improvement of power system se...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Transient stability refers to the ability of a power grid to maintain synchronism during severe disturbances. Methods to improve transient stability include increasing generator rotor size, reducing transmission line reactance, using dynamic braking resistors, independent pole operation of circuit breakers, single pole switching, fast excitation control, fast governor action, generator and load tripping, regulated shunt compensation using static VAR devices, HVDC transmission, and increasing the short circuit ratio. The inertia constant of generators also impacts stability but increasing it is not practical due to increased machine size and cost.
IRJET- Voltage Stability Analysis using Voltage Stability IndicesIRJET Journal
1) The document discusses using the Fast Voltage Stability Index (FVSI) to analyze voltage stability on the IEEE 30-bus test system and identify weak lines and buses.
2) FVSI was calculated for different levels of reactive power loading at three buses. Higher FVSI values indicate lines closer to instability.
3) For bus 26, line 34 was found to be most critical with an FVSI of 0.9571. For bus 30, line 38 was most critical at 0.9325. For bus 29, line 37 was most critical at 0.8421.
4) Analysis of FVSI identified bus 26 as the weakest bus, able to withstand the
Steady state stability analysis and enhancement of three machine nine bus pow...eSAT Journals
This document presents an analysis of steady state stability for the IEEE 3-machine 9-bus test power system. It first describes the mathematical modeling of the system using linearization and state space representation. Eigenvalue analysis shows the system is purely oscillatory without damping. A thyristor controlled phase shifter (TCPS) FACTS device-based controller is then modeled to enhance stability. The system is analyzed with and without the controller. Results show the controller provides damping, improving stability as seen in eigenvalue analysis and time domain simulations following a disturbance.
This document discusses the challenges that African universities face in monitoring and evaluating their performance. It notes that African universities struggle to assemble even basic data on student enrollment, staffing, expenditures, and other metrics. This lack of institutional data makes it difficult for universities to track their own progress and meet the accountability requirements of higher education frameworks. The document argues that African universities need to invest in developing monitoring and evaluation systems to align with new performance-based funding models and demonstrate their relevance and impact. It provides examples of standard performance indicators and initiatives by organizations like NEPAD to collect continental research and development data.
MAI Chem is an indexing solution that helps organizations meet challenges of indexing chemical and pharmaceutical data. It scans documents to identify chemical elements, compounds, synonyms, prefixes, suffixes and process terms. It then presents these as subject indexing terms for editorial review and selection. When used with partner software from CambridgeSoft and ACD/Labs, it allows chemical structures to be automatically generated from the terms identified.
The document discusses the causes and solutions to famine in Somalia. It explains that famine results from a "triple failure" of food production, access to food, and response. In Somalia, a severe drought caused food production to drop by 50% and killed over 90% of livestock, reducing access. The government and international donors also responded too slowly and inadequately to the crisis. To prevent future famines, more investment is needed in African agriculture, rural development to alleviate poverty, and social protections to guarantee access to food. Long-term solutions are required to build resilience against climate shocks and ensure self-sufficiency.
The document discusses an educator named Freddah Numeracy and their interests and goals. They enjoy sharing ideas and telling true stories to motivate learners. At home, they like spending time with their daughter and family. They hope that with continued support from their twin school in England, their school in South Africa will become the best in the country and their teachers the best in the world.
The document provides information on power system stability and transient stability studies. It introduces key concepts such as stability, transient stability studies, rotor dynamics, the swing equation, and the power-angle equation. The swing equation describes the acceleration of a generator's rotor and relates the mechanical input power to the electrical output power. The power-angle equation models the relationship between generator output power and the power angle during transient stability studies.
Transient Stability Assessment and Enhancement in Power SystemIJMER
This document discusses transient stability assessment and enhancement in power systems. It first introduces transient stability and its importance. It then describes using PSAT software to analyze the IEEE 39-bus test system and calculate critical clearing times (CCTs) for different faults to assess stability. An artificial neural network is trained to predict CCTs at different operating points. Finally, particle swarm optimization is used to find the optimal placement of a thyristor controlled series capacitor to enhance stability by minimizing real power losses, increasing several CCTs above 0.1 seconds.
This document discusses various topics related to power system stability including:
1. It defines power system stability as the ability of a system to regain equilibrium after a disturbance. It classifies stability into rotor angle stability, voltage stability, and frequency stability.
2. Rotor angle stability depends on the balance between electromagnetic and mechanical torque on generators. Voltage stability refers to maintaining steady voltages after a disturbance.
3. It derives and explains the swing equation, which describes the relative motion of a generator rotor during disturbances. It provides the swing equation both with and without damper torque.
4. It discusses single machine infinite bus systems and provides the equivalent circuit diagram. Small-signal angle stability refers to the ability of a system
Evolve the Controller for Static Synchronous Series Compensator Based on Cont...IJPEDS-IAES
Real and Reactive power flow in an alternating current transmission line can be independently controlled by connecting, to the transmission line, a series- compensating voltage, which is variable in magnitude and phase angle. The Static Synchronous Series Compensator (SSSC), a solid-state voltage source inverter (VSC) coupled with a transformer, is connected in series with a transmission line. An SSSC injects an almost sinusoidal voltage, of variable magnitude, in series with a transmission line. This injected voltage is almost in quadrature with the line current, thereby emulating an inductive or a capacitive reactance in series with the transmission line. This emulated variable reactance, inserted by the injected voltage source, influences the electric power flow in the transmission line. In this report, an attempt is made to evolve the model of SSSC and VSC with preliminary studies for the controller design.
The Impact of Line Resistance on the Performance of Controllable Series Compe...Editor Jacotech
In recent years controllable FACTS devices are increasingly
integrated into the transmission system. FACTS devices that
provide series control such as Controllable Series Compensator
(CSC) has significant effect on the voltage stability of Electric
Power system. In this work impact of line resistance on the
performance of CSC in a single-load infinitive-bus (SLIB)
model is investigated. The proposed framework is applied to
SLIB model and obtained results demonstrates that line
resistance has considerable effect on voltage stability limits and
performance of CSC.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
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.
This paper proposes using a genetic algorithm to determine the optimal location of a thyristor controlled series capacitor (TCSC) device to enhance available transfer capability (ATC) between source and sink areas in a deregulated power system. The paper simulates placing a TCSC in the IEEE 14-bus test system and uses repeated power flow calculations to compute the ATC with and without the TCSC to determine how much it can enhance transmission capacity.
Transient stability analysis and enhancement of ieee 9 bus system ecij
System stability study is the important parameter of economic, reliable and secure power system planning and operation. Power system studies are important during the planning and conceptual design stages of the project as well as during the operating life of the plant periodically. This paper presents the power system stability analysis for IEEE- 9 bus test system. The fault is created on different busses and transient stability is analyzedfor different load and generation conditions. The critical clearing time (CCT) is calculated by
using time domain classical extended equal area criterion method. The system frequency and voltage variation is observed for different fault locations and CCT. The IEEE-9 bus test system is simulated and stability is analyzed on ETAP software
This document provides an overview of power system stability analysis. It defines power system stability as the ability of a system to maintain equilibrium during normal operation and regain equilibrium after disturbances. It discusses different types of stability including rotor angle stability and voltage stability. Key factors that influence stability like operating conditions, faults, and clearing times are also summarized. Methods for enhancing stability such as high-speed fault clearing and controlled load shedding are briefly mentioned. Models for analyzing stability like the swing equation and equal area criterion are defined in less than 3 sentences.
Comparison of Shunt Facts Devices for the Improvement of Transient Stability ...IJSRD
This paper presents, the performance of STATCOM placed at midpoint of the two machine power system and compared with the performance of SVC. The comparison of various results found for the different type of faults (single line, double line & three phase fault) occur in long transmission line, and their removal by using shunt FACTS devices is analysed. Computer simulation results under a severe disturbance condition (three phase fault) for different fault clearing times, and different line lengths are analyzed. Both controllers are implemented using MATLAB/SIMULINK. Simulation results shows that the STATCOM with conventional PI controller installed with two machine three bus systems provides better damping oscillation characteristics in rotor angle as compared to two machine power system installed with SVC. The transient stability of two machine system installed with STATCOM has been improved considerably and post settling time of the system after facing disturbance is also improved.
This document discusses using a static var compensator (SVC) to improve power system stability in a long transmission line system. It describes how SVCs can effectively control dynamic performance and regulate system voltage. The document presents a MATLAB model of a two-area power system with an SVC installed. Simulation results show that the SVC improves transient stability by reducing rotor angle differences and regulating real and reactive power flows. In conclusion, properly modeling SVC controllers can provide benefits for power system stability studies.
The document analyzes and compares the impact of different shunt compensation devices (shunt capacitor, synchronous phase modifier (SPM), and static VAR compensator (SVC)) on voltage stability enhancement. It identifies the most critical contingency using indices like P-V curves, L-index, and fast voltage stability index (FVSI) for the IEEE 9-bus, 30-bus, and 118-bus test systems. The optimal location and size of the shunt compensator is determined by placing a fictitious generator at the weakest bus. Simulation results show that all three devices can improve voltage stability against load variations, with SPM having slightly higher losses than the other options.
Sensitivity based optimal location of tcsc for improvement of power system se...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Transient stability refers to the ability of a power grid to maintain synchronism during severe disturbances. Methods to improve transient stability include increasing generator rotor size, reducing transmission line reactance, using dynamic braking resistors, independent pole operation of circuit breakers, single pole switching, fast excitation control, fast governor action, generator and load tripping, regulated shunt compensation using static VAR devices, HVDC transmission, and increasing the short circuit ratio. The inertia constant of generators also impacts stability but increasing it is not practical due to increased machine size and cost.
IRJET- Voltage Stability Analysis using Voltage Stability IndicesIRJET Journal
1) The document discusses using the Fast Voltage Stability Index (FVSI) to analyze voltage stability on the IEEE 30-bus test system and identify weak lines and buses.
2) FVSI was calculated for different levels of reactive power loading at three buses. Higher FVSI values indicate lines closer to instability.
3) For bus 26, line 34 was found to be most critical with an FVSI of 0.9571. For bus 30, line 38 was most critical at 0.9325. For bus 29, line 37 was most critical at 0.8421.
4) Analysis of FVSI identified bus 26 as the weakest bus, able to withstand the
Steady state stability analysis and enhancement of three machine nine bus pow...eSAT Journals
This document presents an analysis of steady state stability for the IEEE 3-machine 9-bus test power system. It first describes the mathematical modeling of the system using linearization and state space representation. Eigenvalue analysis shows the system is purely oscillatory without damping. A thyristor controlled phase shifter (TCPS) FACTS device-based controller is then modeled to enhance stability. The system is analyzed with and without the controller. Results show the controller provides damping, improving stability as seen in eigenvalue analysis and time domain simulations following a disturbance.
This document discusses the challenges that African universities face in monitoring and evaluating their performance. It notes that African universities struggle to assemble even basic data on student enrollment, staffing, expenditures, and other metrics. This lack of institutional data makes it difficult for universities to track their own progress and meet the accountability requirements of higher education frameworks. The document argues that African universities need to invest in developing monitoring and evaluation systems to align with new performance-based funding models and demonstrate their relevance and impact. It provides examples of standard performance indicators and initiatives by organizations like NEPAD to collect continental research and development data.
MAI Chem is an indexing solution that helps organizations meet challenges of indexing chemical and pharmaceutical data. It scans documents to identify chemical elements, compounds, synonyms, prefixes, suffixes and process terms. It then presents these as subject indexing terms for editorial review and selection. When used with partner software from CambridgeSoft and ACD/Labs, it allows chemical structures to be automatically generated from the terms identified.
The document discusses the causes and solutions to famine in Somalia. It explains that famine results from a "triple failure" of food production, access to food, and response. In Somalia, a severe drought caused food production to drop by 50% and killed over 90% of livestock, reducing access. The government and international donors also responded too slowly and inadequately to the crisis. To prevent future famines, more investment is needed in African agriculture, rural development to alleviate poverty, and social protections to guarantee access to food. Long-term solutions are required to build resilience against climate shocks and ensure self-sufficiency.
The document discusses an educator named Freddah Numeracy and their interests and goals. They enjoy sharing ideas and telling true stories to motivate learners. At home, they like spending time with their daughter and family. They hope that with continued support from their twin school in England, their school in South Africa will become the best in the country and their teachers the best in the world.
This document outlines eTrøndelag's strategy for digital development in the region. It has four core priorities: digital infrastructure, digital municipality, digital innovation, and digital skills. eTrøndelag aims to make all aspects of digital development understood, explored, and utilized in the region in an appropriate way. Some key initiatives outlined are improving broadband access, coordinating digitalization projects between municipalities, providing advisory resources for innovative digital projects, and enhancing digital skills through programs like "Telecom for municipalities" and "eForum". The overall goal is for eTrøndelag to play a leading role in digital development across the region.
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Building 3D Morphable Models from 2D ImagesShanglin Yang
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Thyristor Controlled Series Capacitor with Automatic Controlijiert bestjournal
An increasingly competitive market where economic a nd environmental pressures limit their scope to expand transmission facilities.The optimiz ation of transmission corridors for power transfer has become a great importance. In this sce nario,the FACTS technology is an attractive option for increasing system operation flexibility [1],New developments in high-current,high- power electronics are making it possible to control electronically the power flows on the high voltage side of the network during both steady stat e and transient operation. In this paper a series controller from the Flexible AC Transmission System (FACTS) family called as �Thyristor Controlled Series Capacitor� (TCSC) is designed using PIC microcontroller. Thyristor controlled series compensator (TCSC),is the first generation of FACTS controller,can govern line impedance through introduction of a thy ristor controlled capacitor in series with the transmission line. A grid of transmission lines ope rating at high voltages is required to transmit power from generating stations to load. In addition to transmission lines that carry power from source to load,modern power systems are highly int erconnected for economic reasons.
Introduction System stability analysis represents one of the common.pdfbkbk37
This document discusses system stability analysis in electrical systems and the role of Flexible AC Transmission System (FACTS) devices in enhancing stability. It provides an overview of different FACTS devices like STATCOM, TCSC, TCPST, SVC, and UPFC. Mathematical models for some key FACTS devices are presented, including the UPFC model using a back-to-back voltage source representation. The controllable power flow regions for TCSC, TCPST and UPFC are compared, showing the UPFC has the largest control region. Transient stability is also discussed, noting some FACTS devices can damp power oscillations and improve transient stability following disturbances.
This document provides an overview of system stability analysis and flexible AC transmission systems (FACTS) devices. It discusses how FACTS devices like STATCOM, SVC, TCSC, and UPFC can improve power system stability, voltage stability, and transient stability through reactive power compensation and active power flow control. Mathematical models of various FACTS devices are also presented to analyze their control capabilities and impact on power flow.
This document discusses modeling and analysis of a Thyristor Controlled Series Capacitor (TCSC) in a power system. It begins with background on TCSC and its benefits for power flow control. It then describes modeling a TCSC circuit using MATLAB Simulink. The model includes components like voltage sources, RLC branches, meters, and a thyristor block. Waveforms are analyzed for the TCSC in capacitive and inductive modes by varying the firing pulse delay. The response stabilizes after a few seconds. Fourier analysis shows the fundamental frequency reaching a new steady-state value with a change in firing angle. In conclusion, the modeling provides insights into the transient behavior and operation of a TCSC.
International Journal of Engineering Research and DevelopmentIJERD Editor
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Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
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Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
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.
Enhancement of Power Quality by an Application FACTS DevicesIAES-IJPEDS
1) The document discusses the use of Flexible AC Transmission Systems (FACTS) devices like Thyristor Controlled Series Capacitor (TCSC) and Thyristor Controlled Reactor (TCR)-based Static VAR Compensator (SVC) to enhance power quality and transmission capability.
2) It presents simulation models of TCSC and TCR-SVC developed using MATLAB/Simulink. The simulations show that these FACTS devices can effectively reduce voltage drops, electrical losses in long transmission lines, and improve stability.
3) Student feedback indicates the models are easy to use and effective for learning about controlled reactor compensators, series capacitor compensators, and reactive power/voltage
Voltage stability using Series FACTS devicesSAI SREE
This document discusses various FACTS devices and their use in enhancing voltage stability. It first defines voltage stability and FACTS devices. FACTS devices are classified as either series or shunt devices depending on their connection type. Series compensation devices like TCSC and SSSC inject voltage in quadrature with line current to control active power flow and reduce line losses. TCSC allows rapid changes to transmission line impedance. SSSC can control both active and reactive power with capacitive and inductive modes of operation. The document concludes that FACTS devices like TCSC and SSSC can improve voltage stability through controlling parameters like voltage, reactance, and power flow in transmission lines.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Implementation of FC-TCR for Reactive Power ControlIOSR Journals
This document discusses the implementation of a Fixed Capacitor Thyristor Controlled Reactor (FC-TCR) system for reactive power control. FC-TCR is a type of Static VAR Compensator (SVC) that can inject or absorb reactive power to control voltage. It consists of a fixed capacitor in parallel with a thyristor controlled reactor. The reactor current is controlled by varying the firing angle of thyristors, allowing both lagging and leading reactive power. MATLAB simulation results show that reactive power output from the FC-TCR increases as the reactor inductance increases while keeping the capacitor constant, demonstrating effective reactive power control.
Hybrid T-I-D and Fuzzy Logic Based SVC Controller for Transient Stability Enh...IJERA Editor
This paper presents a new approach to solve the transient stability problem. The conventional PI based SVC controller has simple functioning and is economical in operation but has sluggish performance with non-linear characteristics. so, in order to circumvent this problem, fuzzy based T-I-D controller has been designed to improve the transient stability of 2 machine 3 bus power system using MATLAB/SIMULINK software.
Impact of hybrid FACTS devices on the stability of the Kenyan power system IJECEIAES
Flexible alternating current transmission system (FACTS) devices are deployed for improving power system’s stability either singly or as a combination. This research investigates hybrid FACTS devices and studies their impact on voltage, small-signal and transient stability simultaneously under various system disturbances. The simulations were done using five FACTS devices-static var compensator (SVC), static synchronous compensator (STATCOM), static synchronous series compensators (SSSC), thyristor controlled series compensator (TCSC) and unified power flow controller (UPFC) in MATLAB’s power system analysis toolbox (PSAT). These five devices were grouped into ten pairs and tested on Kenya’s transmission network under specific contingencies: the loss of a major generating machine and/or transmission line. The UPFC-STATCOM pair performed the best in all the three aspects under study. The settling times were 3 seconds and 3.05 seconds respectively for voltage and rotor angle improvement on the loss of a major generator at normal operation. The same pair gave settling times of 2.11 seconds and 3.12 seconds for voltage and rotor angle stability improvement respectively on the loss of a major transmission line at 140% system loading. From the study, two novel techniques were developed: A performance-based ranking system and classification for FACTS devices.
Improvement the voltage stability margin of Iraqi power system using the opti...IJECEIAES
The detection of potential voltage collapse in power systems is essential to maintain the voltage stability in heavy load demand. This paper proposes a method to detect weak buses in power systems using two stability indices: the voltage stability margin factor (dS/dY) and the voltage collapse prediction index (VCPI). Hence, the paper aims to improve the voltage stability of Iraqi transmission grid by allocating FACTS devices in the optimal locations and optimal sizes. Two types of FACTS are used in this paper which are Thyristor controlled series compensator (TCSC) and static var compensator (SVC). The objective function of the problem is fitted using particle swarm optimization (PSO). The proposed method is verified using simulation test on Diyala-132 kV network which is a part of the Iraqi power system. The results observed that improvement the voltage stability margin, the voltage profile of Diyala-132 kV is increased and the power losses is decreased.
This document discusses reactive power compensation techniques using FACTS (Flexible AC Transmission System) devices. It provides an overview of reactive power and why compensation is needed to regulate voltages and improve stability. Several FACTS devices for reactive power compensation are described, including STATCOM, SVC, TCSC, and UPFC. The document compares these devices based on their ability to control load flow, voltage, and stability. UPFC is found to be most effective for higher load flow control and voltage regulation, while STATCOM is suitable for smaller distribution systems. Reactive power compensation using FACTS devices can enhance power transfer capability and stability.
In any power system, unexpected outages of lines or transformers occur due to faults or other disturbances. These events, referred to as contingencies, may cause significant overloading of transmission lines or transformers. Flexible AC Transmission System (FACTS) controllers provide a new facilities, both in steady state power flow control and dynamic stability control. Thyrister Controlled Series Capacitor (TSCS) based FACTS device for minimize the losses and power flow in long distance transmission line. The problem of determining the optimal TCSC parameters is formulated as an optimization problem and a N-R method based approach is applied to solve the Optimal Power Flow (OPF) problem. Programme is done on 3 bus system by N-R method.
This document discusses power flow management through an Interline Power Flow Controller (IPFC). It begins with an abstract that introduces IPFC as a FACTS controller that can provide balance of reactive and active power between two lines from the same substation through voltage source converters connected in series with the lines and a common DC link. It then provides background on reactive power compensation, FACTS devices, and the operating principles of IPFC. The document establishes equations to model the active and reactive power flows that can be controlled by IPFC. It presents a case study applying the IPFC model to a five bus system and shows that IPFC is effective at controlling power flows between lines.
The document discusses improving power system performance using Flexible AC Transmission System (FACTS) devices. It describes three types of FACTS devices: Static Var Compensator (SVC), Thyristor Controlled Series Compensator (TCSC), and Unified Power Flow Controller (UPFC). The SVC and TCSC are able to control voltage and improve the voltage profile. Simulations showed adding FACTS devices decreased power losses and improved the voltage level. The UPFC can simultaneously control parameters like line impedance, voltage, and phase angle to regulate power flow.
Locating Facts Devices in Optimized manner in Power System by Means of Sensit...IJERA Editor
This document summarizes a research paper that presents a new method for optimally locating Flexible AC Transmission System (FACTS) devices like Static Var Compensators (SVCs) and Thyristor Controlled Series Capacitors (TCSCs) in a power system network. The method uses sensitivity analysis to determine the optimal location and sizing of FACTS devices. It calculates voltage-reactive power sensitivity indices for each bus and line to determine which buses and lines are most sensitive to changes in reactive power. FACTS devices are then optimally located at the bus or line with the highest positive or negative sensitivity index, depending on whether a SVC or TCSC is being placed. The method is tested on the IEEE
The electricity supply industry is undergoing a profound transformation worldwide. Market forces, scarcer natural resources, and an ever-increasing demand for electricity are some of the drivers responsible for such unprecedented change. Against this background of rapid evolution, the expansion programs of many utilities are being thwarted by a variety of well-founded, environment, land-use, and regulatory pressures that prevent the licensing and building of new transmission lines and electricity generating plants.
Locating Facts Devices in Optimized manner in Power System by Means of Sensit...IJERA Editor
This paper presents a new method to find the optimal location of facts devices by analyzing sensitivity . The optimal location and capability of Static Var Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC) in transmission line is investigated for enchasing the power transfer capability and stability of the system. The method firstly put all the buses in the order by voltage reactive power sensitivity and then chooses the optimal location and appropriate capability of the facts devices. It is simple in computation and suitable for large scale interconnection power grid. The results obtained are satisfying and will be useful for enhancing the power system reliability
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“An Assessment of Voltage Stability based on Line Voltage Stability Indices and its Enhancement Using TCSC”
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 10, Issue 6 Ver. I (Nov – Dec. 2015), PP 81-88
www.iosrjournals.org
DOI: 10.9790/1676-10618188 www.iosrjournals.org 81 | Page
“An Assessment of Voltage Stability based on Line Voltage
Stability Indices and its Enhancement Using TCSC”
Merlyn Mathew1
, Sudeshna Ghosh2
, D.Suresh Babu3
, Dr. A.A. Ansari4
1
(M.Tech Scholar, Department of Electrical & Electronics, LNCTE Bhopal (M.P))
2
(Assistant Professor, Department of Electrical & Electronics, LNCTE Bhopal (M.P))
3
(Assistant Professor, Department of Electrical & Electronics, Sree Vidyanikethan Engineering College,
Tirupati (A.P))
4
(Professor & Head, Department of Electrical & Electronics, LNCTE Bhopal (M.P))
Abstract: The issue of voltage instability is becoming a matter of concern throughout the world. It is of
absolute importance to maintain the stability of the power system or it would lead to a condition of total
collapse of the system and ultimately blackout of the whole network. This paper analyses the performance of
line voltage stability indices, Fast Voltage Stability index (FVSI), Line index (LQP), Reactive Power Index
(VQI) and line Stability Index (LMN). These indices are used to identify the most critical line and bus of the
system. Under a condition of single line outage a TCSC is installed at the most critical line and its effect has
been observed. An IEEE 14 bus system is used for simulation purpose.
Keywords: TCSC, FVSI, LQP, VQI, LMN
I. Introduction
The enlarged power demand has desired the attention of the power researchers worldwide, and has
caused the power system to be operated closer to its stability limits. Any situation of power system instability if
not responded to instantaneously can cause a scenario of voltage collapse in the system accompanied by a total
blackout.
A power system is said to have a situation of voltage instability when a disturbance causes a
progressive and uncontrollable decrease in voltage level. Power system stability is the ability of the system to
maintain acceptable levels of voltage at all the buses of the system following a disturbance [1]. Several methods
have been used to analyse the performance of the system stability like the PV Curves, QV Curves, Sensitivity
Analysis, Modal Analysis [2]. An accurate knowledge of how close the actual system’s operating point is from
the voltage stability limit is essential to operators. Therefore, voltage stability index was developed for voltage
stability studies. These indices provide reliable information about proximity of voltage instability in a power
system. Usually, an index value varies between 0 and 1. Line voltage stability indices (LVSI) thus provide
information about the system stability by determining the most severe line in the system [3]. Literatures on the
indices show that several voltage stability indices have been developed for stability analysis studies [5], [6]-[9].
The value of these indices indicate the closeness of the system towards instability, if the index value is closer to
1 it shows that the system is on the verge of instability, if index value is greater than 1, the system has crossed
its stability limit leading to a condition of voltage collapse which can ultimately cause blackout of the system.
Flexible AC Transmission System (FACTS) can be used to enhance the system stability [4] thereby
reducing the seriousness of the system. FACT devices should be installed at the most appropriate location i.e. on
the most critical line as determined by the indices. The advantage of using FACT controllers be it series or shunt
is that the power flow through the line is enhanced and the voltage profile of the system is also improved [10],
[11]. A TCSC is a series FACT controller which provides series compensation in the transmission line in which
it is installed by modifying the value of line reactance, the advantage of using TCSC is that it can be operated in
both inductive and capacitive modes by suitable selection of firing angle [12] ,[13]. Optimal location of TCSC
helps in enhancing the voltages of the buses between which it is placed. This paper proposes to analyse and
enhance the stability of the system using line voltage stability indices thereby reducing the severity of the
system by installing a Thyristor Controlled Series Capacitor (TCSC) in the most critical transmission line.
II. Line Voltage Stability Indices (LVSI)
The line voltage stability indices play a vital role in determining the system stability. They help in
determining the weakest bus and the most critical line in the system so that voltage collapse and hence total
blackout of the system can be interrupted. This paper analyses the effect of some of the line indices on system
stability. These can be briefly discussed as:
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DOI: 10.9790/1676-10618188 www.iosrjournals.org 82 | Page
2.1 Fast Voltage stability index FVSI
The Fast Voltage Stability Index FVSI as proposed by Musirin et al. [5] [6] is also based on the
concept of power flow through a single line. For a typical transmission line, the stability index FVSI is
calculated by the following equation as:
FVSI =
4Z2
Qi
ViX
… … …… … … …(1)
Where,
𝑍 = line impedance
𝑋 = line reactance
𝑄𝑗 = reactive power flow at the receiving end
𝑉𝑖 = sending end voltage
When the FVSI of any line approaches unity it means that the line is approaching its stability limits.
The FVSI of all the lines must be lower than 1 to assure the stability of the power system.
2.2 Line stability factor LQP
Line stability index LQP as defined in [7] can be expressed as:
LQP = 4
X
Vi
X
Vi
2 Pi
2
+ Qj … … …… … … (2)
Where,
𝑋 = line reactance
𝑄𝑗 = reactive power flow at the receiving bus
𝑉𝑖 = voltage at the sending bus
𝑃𝑖 = active power flow at the sending bus.
The line that exhibits LQP value close to 1 implies that it is approaching the instability point. If LQP goes
beyond 1, one of the buses connected to the line experiences a sudden voltage drop leading to system collapse.
2.3 Line stability index LMN
This index also determines the stability of each line connected between two buses in an interconnected
network. As long as the stability index LMN remains (< 1), the system is stable. This voltage stability criterion is
also based on a power transmission concept in a single line [7]. In order to prevent the system from collapse
point the index value should be (< 1). The Line Stability Index LMN is given by:
LMN =
4Xij Qj
Visin θ − δ 2
… … … … … … …(3)
Where,
𝜃 = line impedance angle
δ = angle difference between the sending end and the receiving end voltage
𝑋 = line reactance
𝑄𝑗 = reactive power flow at the receiving end
𝑉𝑖 = sending end voltage
2.4 Reactive power index VQI
The reactive power index is based on the power flow concept through a single transmission line is
given as [8], [9]:
VQI =
4 Qj
Bij Vi
2 … … … …… … … (4)
Where,
𝑄𝑗 = reactive power at the receiving end
𝐵𝑖𝑗 = susceptance of line
𝑉𝑖 = the sending end voltage
The index value (> 1) indicates that the system is on the verge of instability. So as to prevent the
system collapse its value should always be (< 1).
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DOI: 10.9790/1676-10618188 www.iosrjournals.org 83 | Page
III. TCSC
The Thyristor Controlled Series Capacitor (TCSC) is one of the most effective Flexible AC
Transmission System (FACTS) devices. It offers fast-acting reactive power compensation on high-voltage
electricity transmission networks with much faster response compared to the traditional control .TCSC is one of
the most important and best known series FACTS controllers [10]. It has been in use for many years to increase
line power transfer as well as to enhance system stability. Installation of TCSC at the most appropriate location
i.e. at the most stressed line in the system reduces the value of line stability index hence the system stability is
improved. It also helps in improving the voltage profile of the system [11] [12]. The basic construction of a
TCSC is shown in Fig. 1.
Fig 1. A schematic diagram of TCSC
It consists of three components: capacitor C, bypass inductor L and bidirectional thyristors T1 and T2.
The firing angles of the thyristors are controlled to adjust the TCSC reactance in accordance with system
requirements. According to the operating principle of the TCSC, it can control the active power flow for the line
by compensating the transmission line reactance. A TCSC can provide both inductive and capacitive
compensations [13].
3.1 Inductive Mode: TCR is a variable inductive reactor XL α , tuned at firing angle, as shown in Fig. 2. The
variation of XL with respect to alpha α can be given as:
Fig 2. TCSC Inductive Mode
XL α = XL
π
π − 2α − sin2α
…… … … 5
XC =
1
2πfC
… … … (6)
For the variation of α from 0 to 90, XL α varies from actual reactance (XL) to infinity.
3.2 Capacitive Mode: The controlled reactor is connected across the series capacitor, so that the variable
capacitive reactance, as shown in Fig. 3, is possible across the TCSC which modifies the transmission line
impedance. Effective TCSC reactance XTCSC with respect to alpha α can be given as:
Fig 3. TCSC Capacitive Mode
XTCSC α = −XC + C1 2 π − α + sin 2 π − α − C2cos2
π − α ωtan ω π − α − tan π − α … . . (6)
Where,
C1 =
XC + XLC
π
…… … … … 7
C2 = 4
XLC
2
XLπ
… … … …… … . (8)
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DOI: 10.9790/1676-10618188 www.iosrjournals.org 84 | Page
XLC =
XLXC
XC − XL
… … …… … 9
ω =
XC
XL
…… … … …… … . . (10)
IV. Proposed Algorithm
Read the system data
Run the load flow without line outage contingency and use the results as base case
Connect N-1 line outage contingency between any two buses and obtain load flow results
Calculate the values of FVSI , VQI, LMN, and LQP from the equations (1) to (4)
Rank the weakest / most critical line from the base case or line outage contingency condition having highest
value of line indices
Connect TCSC at the most critical line i.e. between load buses (neglecting the generator buses).
Obtain the results with TCSC installed in the line for various capacitive modes of 20% to 55%
compensation.
Compare the calculated values of indices pre and post TCSC placement
V. Case Study & Results
5.1 Results of Line Voltage Stability Indices (LVSI)
The simulation was performed on an IEEE 14 bus system consisting of a slack bus, 4 generator buses,
9 load buses and 20 interconnected lines. The tests were carried out using load flow programs in MATLAB. The
base case results considering all four indices i.e. FVSI, VQI, LMN, LQP show that no critical line and weak
buses were recognized under this condition. Single line outage was carried with one line outage at a time and
results were observed. The results from table reveal that under the condition of line 1-2 outages in the 14 bus
test system, line 1-5 was identified as critical. It can also be seen from table 1 that the same line was observed to
be the most critical line in the system for all four indices. The value of indices being 0.8015, 0.7571, 0.8419 and
1.3136 for FVSI, VQI, LMN and LQP respectively.
5.2 Installation of TCSC
A TCSC was installed in line 1-5 since it showed maximum value of line index and hence was
considered as the most critical line in the system. The effect of TCSC was monitored under different cases of
capacitive compensations as shown in table 2. The variations in the values of line indices for various degrees of
compensation are discussed briefly:
5.2.1Case 1: FVSI
Fig. 4 demonstrates that initially during a single line outage 1-5 the FVSI base case value is 0.8 which
clearly shows that the system in on the verge of instability. Providing different degrees of capacitive
compensation show that there is considerable reduction in the value of FVSI, for 20% compensation index
value reduces to 0.61, 30% - 0.54, 40% - 0.48, 45% - 0.46, 50% - 0.44 and for 55% - 0.42. Thus the severity of
the line is reduced.
Fig. 4 FVSI variation with and without TCSC
0
0.2
0.4
0.6
0.8
1
BASE
CASE
20% 30% 40% 45% 50% 55%
IndexValue
Capacitive Compensation
FVSI
FVSI
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DOI: 10.9790/1676-10618188 www.iosrjournals.org 85 | Page
5.2.2 Case 2: VQI
Fig. 5 illustrates that during a single line outage 1-5 the VQI base case value is found to be 0.77 which
must be lowered to reduce the criticality of the system. Under different degrees of capacitive compensation with
TCSC installation it is seen that there is decrement in the value of VQI, i.e. for 20% compensation index value
reduces to 0.56, 30% - 0.48, 40% - 0.41, 45% - 0.38, 50% - 0.35 and for 55% - 0.33 thereby reducing the line
criticality.
Fig. 5 VQI variation with and without TCSC
5.2.3 Case 3: LMN
Fig. 6 indicates that during a single line outage 1-5 the LMN base case value is 0.84 which clearly
reveals that the system in close to instability. Installing TCSC and providing different degrees of capacitive
compensation show that there is considerable reduction in the value of LMN, i.e. for 20% compensation index
value lowers to 0.57, 30% - 0.48, 40% - 0.41, 45% - 0.39, 50% - 0.36 and for 55% - 0.34. Thus the seriousness
of the line is reduced.
Fig. 6 LMN variation with and without TCSC
5.2.4Case 4: LQP
Fig. 7 shows that the LQP base case value which occurs during a single line outage 1-5 is 1.31 which
explains that the system has crossed its stability limits with index value exceeding 1 and can consequently cause
a total collapse of the entire system. TCSC installation can help to reduce the system instability by lowering the
index values under different degrees of capacitive compensation, i.e. for 20% compensation index value lowers
to 0.95, 30% - 0.78, 40% - 0.63, 45% - 0.56, 50% - 0.49 and for 55% - 0.43. Thus the collapse of the system can
be prevented with the effective use of TCSC.
0
0.2
0.4
0.6
0.8
BASE
CASE
20% 30% 40% 45% 50% 55%
Indexvalue
Capacitive Compensation
VQI
VQI
0
0.2
0.4
0.6
0.8
1
BASE
CASE
20% 30% 40% 45% 50% 55%
IndexValue
Capacitive Compensation
LMN
LMN
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Fig. 7 LQP variation with and without TCSC
5.2.5Voltage Profile
Figure 8 depicts the deviations in the voltages of bus 5 due to the placement of TCSC in line 1-5, it can
be seen that there is an improvement in the voltage level of bus 5 from 0.993 during base case to a maximum of
0.998 during 30 and 40 % compensation, further to 0.996 and 0.995 for 50 % and 55% compensation
respectively.
Fig.8 Voltage profile of bus 5
VI. Conclusion
The line voltage stability indices aid in determining the closeness of the system towards instability. The
values of these indices are convenient in indentifying the most critical line in the system. A TCSC is installed in
the most severe line and as a result enhanced values of line voltage stability indices are obtained. Thus, the
severity of the line is reduced. As a result the voltage profile of the system is also enhanced.
Acknowledgement
The authors are grateful and obliged to the management of Lakhsmi Narain College of Technology
Excellence for their cooperation and support during the research work.
References
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0
0.2
0.4
0.6
0.8
1
1.2
1.4
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Appendix
Table 1 Line indices under single line outage condition
Table 2 Line index values with TCSC compensation
1 2 0.0637 0.0000 0.0585 0.0067 0.0608 0.0075 0.0667 0.0067
1 5 0.0256 0.8015 0.0242 0.7571 0.0244 0.8419 0.0982 1.3136
2 3 0.0113 0.0532 0.0107 0.0503 0.0108 0.0514 0.0706 0.0588
2 4 0.0194 0.1844 0.0175 0.1664 0.0184 0.1858 0.0365 0.1664
2 5 0.0178 0.2836 0.0161 0.2562 0.0171 0.3003 0.0231 0.2564
3 4 0.0384 0.1694 0.0333 0.1469 0.0398 0.1849 0.0339 0.1490
4 5 0.0261 0.1067 0.0237 0.0970 0.0266 0.1118 0.0239 0.0978
4 7 0.0919 0.1272 0.0919 0.1272 0.0921 0.1275 0.0927 0.1276
4 9 0.0371 0.0658 0.0371 0.0658 0.0374 0.0661 0.0476 0.0700
5 6 0.0779 0.0458 0.0779 0.0458 0.0786 0.0464 0.0904 0.0798
6 11 0.0293 0.0333 0.0238 0.0271 0.0290 0.0328 0.0238 0.0271
6 12 0.0259 0.0257 0.0210 0.0209 0.0255 0.0254 0.0210 0.0210
6 13 0.0389 0.0404 0.0309 0.0321 0.7089 0.7226 0.0309 0.0321
7 8 0.1101 0.1437 0.1101 0.1437 0.1101 0.1437 0.1101 0.1437
7 9 0.0195 0.0236 0.0195 0.0236 0.0195 0.0236 0.0197 0.0237
9 10 0.0145 0.0134 0.0127 0.0117 0.0145 0.0134 0.0127 0.0117
9 14 0.0399 0.0388 0.0327 0.0318 0.0392 0.0383 0.0328 0.0318
10 11 0.0134 0.0175 0.0113 0.0148 0.0135 0.0177 0.0113 0.0148
12 13 0.0120 0.0116 0.0054 0.0052 0.0119 0.0116 0.0054 0.0052
13 14 0.0255 0.0280 0.0206 0.0225 0.0252 0.0274 0.0206 0.0227
LMN
BASE CASE
LMN
1-2 OUTAGE
LQP
BASE CASE
LQP
1-2 OUTAGE
VQI
1-2 OUTAGE
FROM
BUS
TO
BUS
FVSI
BASE CASE
FVSI
1-2 OUTAGE
VQI
BASE CASE
FVSI VQI LMN LQP
BASE CASE 0.8015 0.7571 0.8419 1.3136
20% 0.6157 0.5639 0.5769 0.9574
30% 0.5448 0.4865 0.4881 0.7859
40% 0.4870 0.4188 0.4196 0.6334
45% 0.4638 0.3885 0.3923 0.5638
50% 0.4440 0.3596 0.3689 0.4981
55% 0.4284 0.3321 0.3479 0.4363
LINE 1-5 UNDER 1-2 LINE OUTAGE