This paper presents a critical study of modulation strategies for three level Diode Clamped Volta... more This paper presents a critical study of modulation strategies for three level Diode Clamped Voltage Source Inverter (DCVSI) for grid connected wind turbine. The survey is carried out on two types of modulation techniques popularly used in three level DCVSI, viz. Sinusoidal PWM and Space vector PWM. Purpose of the survey is to critically analyze and identify the problems associated with existing DCVSI used in grid connection. It is observed from the study that the three level DCVSI suffers from narrow pulse width and capacitor voltage imbalance, which would be more predominant with higher rated wind turbine. Further this problem results in inefficient performance of DCVSI, there by affecting the power quality. The study also reveals that the existing modulation techniques, even though popular in drive application, fail to meet the present requirements of grid connection. Observations from the study will be of much use to investigators, to develop modulation strategies to overcome the said problems for grid connection of wind turbines. This study is part of research project entitled "Development of FPGA-DSP Controlled Multilevel Inverter Interface for Grid Connection of Wind Turbine Generators" funded by All India Council Technical Education (AICTE), New Delhi, India.
Assessment of wind for a particular site is gaining importance to install an appropriate wind tur... more Assessment of wind for a particular site is gaining importance to install an appropriate wind turbine at a particular site. The Weibull distribution function is widely accepted for evaluating the wind probability using scale and shape parameter. This paper presents modeling of scale and shape parameter to assess the wind potential at a selected wind site. A case study is
In this paper a new methodology to select a wind turbine generator from the view point of perform... more In this paper a new methodology to select a wind turbine generator from the view point of performance and economic considerations is presented. Weibull probability density function is used to analyze the wind data and the performance analysis is based on computing the capacity factors. The economic considerations involve computation of cost of energy based on the energy yield, capital cost, operation and maintenance costs and fixed charge rate of the wind turbines under study at the site. The wind site selected for the study is located at Basaveshwar Engineering College Bagalkot, Karnataka, India. Wind velocities are recorded from a 50-meter wind mast set up under the research grant received from Technical Education Quality Improvement Program of the World Bank. The period of measurement of wind velocities is from June 2007 to May 2008. Four small wind turbine generators of size 0.4 kW, 0.65 kW, 1.5 kW and 4.2 kW respectively and locally available in India are used for the study. A novel methodology to compute economic index to select economically viable wind turbine generator is derived and presented in the paper. Economic indices for the four turbines under study are computed. A detailed discussion of the results to select an economically viable wind turbine generator is presented.
A new transmission system- Fractional Frequency Transmission System (FFTS) proposed in the litera... more A new transmission system- Fractional Frequency Transmission System (FFTS) proposed in the literature is a promising alternative to High-Voltage (HV), High Voltage Direct Current (HVDC) and Flexible AC Transmission System (FACTS) technology to increase power transfer capability and to improve voltage profile of the transmission line. In this paper three studies of FFTS are presented to investigate its feasibility. Firstly, a comparative analysis of performance of FFTS and conventional 50 Hz line is presented. Performance is evaluated by using power flow equations. The results show that the power transfer capability of FFTS line is several multiple of than that of conventional 50 Hz line. Secondly, a comparative analysis of stability of FFTS and conventional 50 Hz system is presented. Magnetic frequency changer is employed as frequency tripler. The simulation model of FFTS and conventional 50 Hz system is developed in Simulink platform of MATLAB and stability is assessed under different contingencies. The results show that, rotor swings of FFTS are compatible with conventional 50 Hz system. Lastly, comparative analysis of design parameters of FFTS and conventional transformer is presented. Synthesis approach is used for evaluation of design parameters. The results show that, FFTS transformer is costlier. Thus it is concluded that, FFTS is feasible and stable and there is no essential difficulty for practicing it in engineering.
The intermittent nature of wind draws its attention for reliability evaluation to penetrate more ... more The intermittent nature of wind draws its attention for reliability evaluation to penetrate more in conventional power system. This paper presents a case study on reliability evaluation of three wind farms in North Karnataka region. The main objective of this study is to identify a reliable site based on the wind data analysis of historical wind speeds using Weibull distribution. The study illustrates that the reliability decreases with increase in load demand. Further, for a specified load demand at any time instant, reliability increases with increase in hub height. The usefulness of the present study in the site selection for wind power generation is demonstrated through detailed analysis.
Application of renewable energy sources in electric power systems is growing rapidly due to enhan... more Application of renewable energy sources in electric power systems is growing rapidly due to enhanced public concern for adverse environmental impacts and escalation in energy costs and shortage of fossil fuels associated with the use of conventional energy sources throughout the world. Environmental concerns and fuel cost uncertainties associated with the use these energy sources have resulted in rapid growth of wind energy applications in power generating systems. The wind turbine generators are the alternatives for electric power generating systems due to their non exhausted nature and benign environmental effects. Therefore, in this study, wind data collected over a period of one year at three different commercial wind farms were analyzed in order to figure out the wind energy potential along the west central part of Karnataka, India. The wind data from selected stations have been collected and analyzed using two-parameter Weibull distribution. From the simulation result it can be concluded that out of three wind farms, EP-02 (road 2) is the one of the best site for optimal energy production. This paper presents few significant conclusions related assessment of wind power potential. The Weibull distribution model will be useful to the wind energy conversion system and utilities in making a judicious choice of a wind site with optimally matched wind turbines.
This paper presents Particle Swarm Optimization and Perturbation & Observation techniques to find... more This paper presents Particle Swarm Optimization and Perturbation & Observation techniques to find the optimum operating parameters of a solar photovoltaic panel under varying atmospheric conditions. The terminal voltage, current and corresponding duty-cycle, at which the DC/DC converter should be switched to obtain maximum power output, are determined. Simulation of maximum power point tracking of a DSP210 solar panel is done, using both methods, in MATLAB. It is observed from the results that the particle swarm optimization based algorithm can track the maximum power point for the whole range of solar data (irradiance and temperature) and has high conversion performance.
Voltage regulation is an important subject in electrical distribution system. The voltage drop al... more Voltage regulation is an important subject in electrical distribution system. The voltage drop along primary distribution systems has been a crucial operating problem, especially for lengthy feeders, with a significant load concentration at their ends. As the load on a feeder varies the voltage supplied to every customer will also vary. It is the utilities responsibility to keep the customer voltage within American National Standard Institution (ANSI) standard. In order to satisfy the ANSI standard, the utility must have means of regulating the feeder voltage. In view of this, a model of control system for voltage regulator (VR) is developed and tested. The paper presents modeling of control system for voltage regulator, which is On-Load Tap Changing (OLTC) transformer. The control system model is developed using MiPower software. The model is tested for 12 bus and 70 bus radial distribution systems. Further a case study is done for optimal placement of voltage regulator for the said systems. The Placement of voltage regulator is done with help of a two different algorithms. These algorithms help to find the location and number of voltage regulator required for systems. Finally comparison of two algorithms is done to select best method for the placement of voltage regulator. The voltage profile of the systems are improved and real power losses occurred for the systems with VR are less. The first algorithm gave good results with respect to reduction of losses and economical aspects.
This paper presents a critical study of modulation strategies for three level Diode Clamped Volta... more This paper presents a critical study of modulation strategies for three level Diode Clamped Voltage Source Inverter (DCVSI) for grid connected wind turbine. The survey is carried out on two types of modulation techniques popularly used in three level DCVSI, viz. Sinusoidal PWM and Space vector PWM. Purpose of the survey is to critically analyze and identify the problems associated with existing DCVSI used in grid connection. It is observed from the study that the three level DCVSI suffers from narrow pulse width and capacitor voltage imbalance, which would be more predominant with higher rated wind turbine. Further this problem results in inefficient performance of DCVSI, there by affecting the power quality. The study also reveals that the existing modulation techniques, even though popular in drive application, fail to meet the present requirements of grid connection. Observations from the study will be of much use to investigators, to develop modulation strategies to overcome the said problems for grid connection of wind turbines. This study is part of research project entitled "Development of FPGA-DSP Controlled Multilevel Inverter Interface for Grid Connection of Wind Turbine Generators" funded by All India Council Technical Education (AICTE), New Delhi, India.
Assessment of wind for a particular site is gaining importance to install an appropriate wind tur... more Assessment of wind for a particular site is gaining importance to install an appropriate wind turbine at a particular site. The Weibull distribution function is widely accepted for evaluating the wind probability using scale and shape parameter. This paper presents modeling of scale and shape parameter to assess the wind potential at a selected wind site. A case study is
In this paper a new methodology to select a wind turbine generator from the view point of perform... more In this paper a new methodology to select a wind turbine generator from the view point of performance and economic considerations is presented. Weibull probability density function is used to analyze the wind data and the performance analysis is based on computing the capacity factors. The economic considerations involve computation of cost of energy based on the energy yield, capital cost, operation and maintenance costs and fixed charge rate of the wind turbines under study at the site. The wind site selected for the study is located at Basaveshwar Engineering College Bagalkot, Karnataka, India. Wind velocities are recorded from a 50-meter wind mast set up under the research grant received from Technical Education Quality Improvement Program of the World Bank. The period of measurement of wind velocities is from June 2007 to May 2008. Four small wind turbine generators of size 0.4 kW, 0.65 kW, 1.5 kW and 4.2 kW respectively and locally available in India are used for the study. A novel methodology to compute economic index to select economically viable wind turbine generator is derived and presented in the paper. Economic indices for the four turbines under study are computed. A detailed discussion of the results to select an economically viable wind turbine generator is presented.
A new transmission system- Fractional Frequency Transmission System (FFTS) proposed in the litera... more A new transmission system- Fractional Frequency Transmission System (FFTS) proposed in the literature is a promising alternative to High-Voltage (HV), High Voltage Direct Current (HVDC) and Flexible AC Transmission System (FACTS) technology to increase power transfer capability and to improve voltage profile of the transmission line. In this paper three studies of FFTS are presented to investigate its feasibility. Firstly, a comparative analysis of performance of FFTS and conventional 50 Hz line is presented. Performance is evaluated by using power flow equations. The results show that the power transfer capability of FFTS line is several multiple of than that of conventional 50 Hz line. Secondly, a comparative analysis of stability of FFTS and conventional 50 Hz system is presented. Magnetic frequency changer is employed as frequency tripler. The simulation model of FFTS and conventional 50 Hz system is developed in Simulink platform of MATLAB and stability is assessed under different contingencies. The results show that, rotor swings of FFTS are compatible with conventional 50 Hz system. Lastly, comparative analysis of design parameters of FFTS and conventional transformer is presented. Synthesis approach is used for evaluation of design parameters. The results show that, FFTS transformer is costlier. Thus it is concluded that, FFTS is feasible and stable and there is no essential difficulty for practicing it in engineering.
The intermittent nature of wind draws its attention for reliability evaluation to penetrate more ... more The intermittent nature of wind draws its attention for reliability evaluation to penetrate more in conventional power system. This paper presents a case study on reliability evaluation of three wind farms in North Karnataka region. The main objective of this study is to identify a reliable site based on the wind data analysis of historical wind speeds using Weibull distribution. The study illustrates that the reliability decreases with increase in load demand. Further, for a specified load demand at any time instant, reliability increases with increase in hub height. The usefulness of the present study in the site selection for wind power generation is demonstrated through detailed analysis.
Application of renewable energy sources in electric power systems is growing rapidly due to enhan... more Application of renewable energy sources in electric power systems is growing rapidly due to enhanced public concern for adverse environmental impacts and escalation in energy costs and shortage of fossil fuels associated with the use of conventional energy sources throughout the world. Environmental concerns and fuel cost uncertainties associated with the use these energy sources have resulted in rapid growth of wind energy applications in power generating systems. The wind turbine generators are the alternatives for electric power generating systems due to their non exhausted nature and benign environmental effects. Therefore, in this study, wind data collected over a period of one year at three different commercial wind farms were analyzed in order to figure out the wind energy potential along the west central part of Karnataka, India. The wind data from selected stations have been collected and analyzed using two-parameter Weibull distribution. From the simulation result it can be concluded that out of three wind farms, EP-02 (road 2) is the one of the best site for optimal energy production. This paper presents few significant conclusions related assessment of wind power potential. The Weibull distribution model will be useful to the wind energy conversion system and utilities in making a judicious choice of a wind site with optimally matched wind turbines.
This paper presents Particle Swarm Optimization and Perturbation & Observation techniques to find... more This paper presents Particle Swarm Optimization and Perturbation & Observation techniques to find the optimum operating parameters of a solar photovoltaic panel under varying atmospheric conditions. The terminal voltage, current and corresponding duty-cycle, at which the DC/DC converter should be switched to obtain maximum power output, are determined. Simulation of maximum power point tracking of a DSP210 solar panel is done, using both methods, in MATLAB. It is observed from the results that the particle swarm optimization based algorithm can track the maximum power point for the whole range of solar data (irradiance and temperature) and has high conversion performance.
Voltage regulation is an important subject in electrical distribution system. The voltage drop al... more Voltage regulation is an important subject in electrical distribution system. The voltage drop along primary distribution systems has been a crucial operating problem, especially for lengthy feeders, with a significant load concentration at their ends. As the load on a feeder varies the voltage supplied to every customer will also vary. It is the utilities responsibility to keep the customer voltage within American National Standard Institution (ANSI) standard. In order to satisfy the ANSI standard, the utility must have means of regulating the feeder voltage. In view of this, a model of control system for voltage regulator (VR) is developed and tested. The paper presents modeling of control system for voltage regulator, which is On-Load Tap Changing (OLTC) transformer. The control system model is developed using MiPower software. The model is tested for 12 bus and 70 bus radial distribution systems. Further a case study is done for optimal placement of voltage regulator for the said systems. The Placement of voltage regulator is done with help of a two different algorithms. These algorithms help to find the location and number of voltage regulator required for systems. Finally comparison of two algorithms is done to select best method for the placement of voltage regulator. The voltage profile of the systems are improved and real power losses occurred for the systems with VR are less. The first algorithm gave good results with respect to reduction of losses and economical aspects.
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