International Journal of Power and Energy Conversion http://www.inderscience.com/browse/index.php?journalID=312&year=2012&vol=3&issue=1/2 Inderscience Publishers Ltd en-uk International Journal of Power and Energy Conversion 1757-1154 1757-1162 © 2012 Inderscience Publishers Ltd editor@inderscience.com https://www.inderscience.com/images/files/coverImgs/ijpec_scoverijpec.jpg http://www.inderscience.com/browse/index.php?journalID=312&year=2012&vol=3&issue=1/2 http://www.inderscience.com/link.php?id=44281 This paper presents Lagrangian-based technique to solve economic emission load dispatch (EELD) of valve-point loaded generating units considering emission constraint. The EELD problem has gained recent attention due to the deregulation of power industry and environmental regulations. In this paper, two conflicting functions (fuel cost and emission) are considered and formulated as a single objective optimisation problem by the weighted sum method. Based on the literature survey, it is found that cost function is taken as a quadratic function and solved for emission economic dispatch. Here, in cost function, a sine term is added to model the valve-point effect and an exponential term is used to model the emission function. Using Maclaurin series, the sine and exponential terms are expanded and solved with Lagrangian multiplier method. The objective function is highly non-linear and the feasibility of the proposed method is validated with IEEE 30-bus system and ten-unit system. Results obtained with the proposed approach are compared with genetic algorithm. Emission constrained economic dispatch with valve-point effect using Maclaurin series-based Lagrangian method
S. Hemamalini; Sishaj P. Simon
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 1 - 18
This paper presents Lagrangian-based technique to solve economic emission load dispatch (EELD) of valve-point loaded generating units considering emission constraint. The EELD problem has gained recent attention due to the deregulation of power industry and environmental regulations. In this paper, two conflicting functions (fuel cost and emission) are considered and formulated as a single objective optimisation problem by the weighted sum method. Based on the literature survey, it is found that cost function is taken as a quadratic function and solved for emission economic dispatch. Here, in cost function, a sine term is added to model the valve-point effect and an exponential term is used to model the emission function. Using Maclaurin series, the sine and exponential terms are expanded and solved with Lagrangian multiplier method. The objective function is highly non-linear and the feasibility of the proposed method is validated with IEEE 30-bus system and ten-unit system. Results obtained with the proposed approach are compared with genetic algorithm.

]]> 10.1504/IJPEC.2012.044281 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 1 - 18 S. Hemamalini; Sishaj P. Simon Department of Electrical and Electronics Engineering, National Institute of Technology, Tiruchirappalli-620 015, Tamil Nadu, India. ' Department of Electrical and Electronics Engineering, National Institute of Technology, Tiruchirappalli-620 015, Tamil Nadu, India economic dispatch emission dispatch Maclaurin series genetic algorithms GAs valve-point loading emission constraints fuel costs emissions. 2011-12-19T23:20:50-05:00 3 1/2 1 18 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44297 The switched reluctance motor (SRM) is intended to operate in deep magnetic saturation to increase the output power density. Because of the saturation effect and the variation of magnetic reluctance with respect to rotor position, all the relevant characteristics of the machine are highly non-linear functions of both rotor position and phase current. The ultimate outcome of all these non-linearities is that the generated torque contains significant ripples. Determination of appropriate phase current profile for generating torque in SRM with minimum ripples poses a lot of difficulty owing to the non-linear magnetic characteristics. A new method is introduced in this work that computes inductance gradient at each rotor position and phase current to modulate the phase current which produces zero torque ripples. The experimental results indicate that the torque ripple is reduced to lie within 5% of the desired steady torque even in dynamic operating conditions. Torque ripple minimisation in SR motors using phase inductance gradient compensation technique
R. Gobbi; K. Ramar
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 19 - 41
The switched reluctance motor (SRM) is intended to operate in deep magnetic saturation to increase the output power density. Because of the saturation effect and the variation of magnetic reluctance with respect to rotor position, all the relevant characteristics of the machine are highly non-linear functions of both rotor position and phase current. The ultimate outcome of all these non-linearities is that the generated torque contains significant ripples. Determination of appropriate phase current profile for generating torque in SRM with minimum ripples poses a lot of difficulty owing to the non-linear magnetic characteristics. A new method is introduced in this work that computes inductance gradient at each rotor position and phase current to modulate the phase current which produces zero torque ripples. The experimental results indicate that the torque ripple is reduced to lie within 5% of the desired steady torque even in dynamic operating conditions.

]]> 10.1504/IJPEC.2012.044297 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 19 - 41 R. Gobbi; K. Ramar Faculty of Engineering, The University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia. ' Faculty of Engineering, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor, Malaysia SR motors torque ripples gradient compensation current modulation power conversion switched reluctance motors. 2011-12-19T23:20:50-05:00 3 1/2 19 41 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44282 This paper presents a modified particle swarm optimisation (PSO) algorithm for solving optimal power flow (OPF) problem through the application of Gaussian and Cauchy probability distributions. The modified PSO approach introduces diversification into the particle thus preventing PSO algorithm from premature convergence. The controllable system quantities are optimised to minimise fuel cost of the power generation. An IEEE 30-bus system is taken for investigation. The optimal power flow results obtained using modified PSO are compared with those obtained using standard PSO, GA and conventional methods. The investigation reveals that the proposed algorithm is relatively simple, reliable and efficient and suitable for online applications. Particle swarm optimisation technique using Gaussian and Cauchy probability distribution function for optimal power flow problem
N. Balasubramanian Muthuselvan; P. Somasundaram
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 42 - 53
This paper presents a modified particle swarm optimisation (PSO) algorithm for solving optimal power flow (OPF) problem through the application of Gaussian and Cauchy probability distributions. The modified PSO approach introduces diversification into the particle thus preventing PSO algorithm from premature convergence. The controllable system quantities are optimised to minimise fuel cost of the power generation. An IEEE 30-bus system is taken for investigation. The optimal power flow results obtained using modified PSO are compared with those obtained using standard PSO, GA and conventional methods. The investigation reveals that the proposed algorithm is relatively simple, reliable and efficient and suitable for online applications.

]]> 10.1504/IJPEC.2012.044282 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 42 - 53 N. Balasubramanian Muthuselvan; P. Somasundaram Department of Electrical and Electronics Engineering, SSN College of Engineering, Old Mahabalipuram Road SSN Nagar - 603 110 Tamil Nadu, India. ' Department of Electrical and Electronics Engineering, SSN College of Engineering, Old Mahabalipuram Road SSN Nagar - 603 110 Tamil Nadu, India optimal power flow OPF particle swarm optimisation PSO Gaussian probability distribution Cauchy probability distribution fuel costs. 2011-12-19T23:20:50-05:00 3 1/2 42 53 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44284 In the last few years, electricity markets have significantly restructured in both developed and developing countries. Accurate prediction of day-ahead electricity nodal price has now become an important activity to address the price volatility in the marketplace. This will facilitate the market participants to estimate the risk and have effective decision-making in formulating bidding strategy. In developing countries, transmission congestion and investment problems have reduced the consumer benefits. Recent trend is to incorporate high voltage direct current (HVDC) transmission in the AC transmission system to gain its techno-economical advantages. This study aims at 1) motivation and relevance of present study; 2) presenting AC-DC OPF nodal pricing and formulating ANN-based peak day-ahead nodal price prediction using multilayer feed-forward neural network with a back-propagation algorithm; 3) the numerical results of IEEE 30-bus system and a real electricity market of India to demonstrate the rationality and feasibility of the proposed methodology. Day-ahead AC-DC OPF-based nodal price prediction by artificial neural network (ANN) in a restructured electricity market
S.B. Warkad; M.K. Khedkar; G.M. Dhole
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 54 - 76
In the last few years, electricity markets have significantly restructured in both developed and developing countries. Accurate prediction of day-ahead electricity nodal price has now become an important activity to address the price volatility in the marketplace. This will facilitate the market participants to estimate the risk and have effective decision-making in formulating bidding strategy. In developing countries, transmission congestion and investment problems have reduced the consumer benefits. Recent trend is to incorporate high voltage direct current (HVDC) transmission in the AC transmission system to gain its techno-economical advantages. This study aims at 1) motivation and relevance of present study; 2) presenting AC-DC OPF nodal pricing and formulating ANN-based peak day-ahead nodal price prediction using multilayer feed-forward neural network with a back-propagation algorithm; 3) the numerical results of IEEE 30-bus system and a real electricity market of India to demonstrate the rationality and feasibility of the proposed methodology.

]]> 10.1504/IJPEC.2012.044284 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 54 - 76 S.B. Warkad; M.K. Khedkar; G.M. Dhole Electrical Engineering Department, Visvesvaraya National Institute of Technology, Nagpur-440010, India. ' Electrical Engineering Department, Visvesvaraya National Institute of Technology, Nagpur-440010, India. ' Electrical Engineering Department, Shri Sant Gajanan Maharaj College of Engineering, Shegaon, Maharashtra-444203, India restructured electricity markets optimal power flow AC-DC OPF nodal price prediction artificial neural networks ANNs developing countries India. 2011-12-19T23:20:50-05:00 3 1/2 54 76 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44300 Over the past two decades, several countries have restructured their electricity industry by significantly reducing the government's role in the ownership and management of energy sector. The generation sector was the first activity of the vertically integrated industry to be open for the competition and therefore, it presents the highest level of competitiveness and experience. In the new restructured electricity markets, the objective of each generation company (GENCO) is to maximise its total expected profit over a planning horizon while following the grid-code and system operators' directive for the safe operation of the power system. In the expansion plan of generating companies, the problem is to be reformulated incorporating several uncertainty factors such as demand growth, the volatility of market prices for electricity and fuels, delay in project completion, financial constraints, etc. In this paper, a long-term multi-period expansion model for a generation company operating in the deregulated electricity industry is presented. The effectiveness of the proposed approach is demonstrated on numerical examples. GENCOs multiperiod expansion model in a competitive electricity market
Daniel Hernández-González; Guillermo Gutiérrez-Alcaraz; S.N. Singh
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 77 - 93
Over the past two decades, several countries have restructured their electricity industry by significantly reducing the government's role in the ownership and management of energy sector. The generation sector was the first activity of the vertically integrated industry to be open for the competition and therefore, it presents the highest level of competitiveness and experience. In the new restructured electricity markets, the objective of each generation company (GENCO) is to maximise its total expected profit over a planning horizon while following the grid-code and system operators' directive for the safe operation of the power system. In the expansion plan of generating companies, the problem is to be reformulated incorporating several uncertainty factors such as demand growth, the volatility of market prices for electricity and fuels, delay in project completion, financial constraints, etc. In this paper, a long-term multi-period expansion model for a generation company operating in the deregulated electricity industry is presented. The effectiveness of the proposed approach is demonstrated on numerical examples.

]]> 10.1504/IJPEC.2012.044300 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 77 - 93 Daniel Hernández-González; Guillermo Gutiérrez-Alcaraz; S.N. Singh Departamento de Ingeniería en Mecatrónica y Sistemas Productivos, Universidad Tecnológica del Valle de Toluca, Carretera del Departamento del D.F. km 7.5, Ejido de Santa María Atarasquillo, Lerma, Mexico. ' Departamento de Ingeniería Eléctrica y Electrónica, Programa de Graduados e Investigación en Ingeniería Eléctrica, Instituto Tecnológico de Morelia, Av. Tecnológico 1500, Col. Lomas de Santiaguito 58120, Morelia Michoacán, Mexico. ' Department of Electrical Engineering, Indian Institute of Technology Kanpur, Kanpur-208016, India generation expansion planning GEP profit maximisation uncertainty electricity markets modelling. 2011-12-19T23:20:50-05:00 3 1/2 77 93 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44285 A huge number of wind generators are going to be connected with the existing network in the near future. Therefore, it is necessary to analyse various models of wind energy conversion systems (WECS) for the purpose of studying the impacts upon grid. This paper presents comparative study on grid connected WECS having two different wind turbine generator systems (WTGS): model 1 [WTGS having doubly fed induction generators (DFIGs)] and model 2 [WECS having permanent magnet synchronous generators (PMSG)]. Both models are connected to AC grid through an efficient power electronic interface. Transient simulations are carried out under the condition of sudden short circuit disturbance and effect of increased generator inertia constant, friction factor and base speed is analysed. The power quality is also analysed in terms of total harmonic distortion (THD) for both models and steps are taken to improve the power quality by reducing THD. A comparative study on the grid integrated wind energy conversion systems (WECS) using different generator models
Lata Gidwani; H.P. Tiwari
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 94 - 100
A huge number of wind generators are going to be connected with the existing network in the near future. Therefore, it is necessary to analyse various models of wind energy conversion systems (WECS) for the purpose of studying the impacts upon grid. This paper presents comparative study on grid connected WECS having two different wind turbine generator systems (WTGS): model 1 [WTGS having doubly fed induction generators (DFIGs)] and model 2 [WECS having permanent magnet synchronous generators (PMSG)]. Both models are connected to AC grid through an efficient power electronic interface. Transient simulations are carried out under the condition of sudden short circuit disturbance and effect of increased generator inertia constant, friction factor and base speed is analysed. The power quality is also analysed in terms of total harmonic distortion (THD) for both models and steps are taken to improve the power quality by reducing THD.

]]> 10.1504/IJPEC.2012.044285 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 94 - 100 Lata Gidwani; H.P. Tiwari Department of Electrical Engineering, Govt. Engineering College, Ajmer, Rajasthan, India. ' Department of Electrical Engineering, Malaviya National Institute of Technology, Jaipur, Rajasthan, India wind turbines wind generators WTGS efficient power electronics power electronics interface total harmonic distortion THD wind energy conversion systems WECS power quality grid connection wind power. 2011-12-19T23:20:50-05:00 3 1/2 94 100 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44288 When an internal fault occurs in a synchronous generator, the symmetry between the parallel paths of the winding is broken and different currents flow in them, due to unsymmetrical magnetic linkage between the stator windings. The aim of this paper is to present a simulation model to investigate the effect of internal fault on the parallel path currents of a large synchronous generator using direct phase quantities. This model is based on a modified winding function approach where the machine inductances are calculated directly from the machine winding distribution using machine electrical parameters instead of the geometrical ones. The simulation results for different cases of internal faults in salient-pole and non-salient-pole synchronous machines have been obtained. Salient-pole synchronous generator has wave winding distribution while the non-salient-pole generator has lap winding arrangement. Due to different stator winding arrangements, the two machines have been simulated individually. By using the simulated fault data, a suitable numerical protection scheme for synchronous generators can be developed. Modelling and simulation of faults in synchronous generators for robust numerical protection
Amrita Sinha; D.N. Vishwakarma; R.K. Srivastava
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 111 - 126
When an internal fault occurs in a synchronous generator, the symmetry between the parallel paths of the winding is broken and different currents flow in them, due to unsymmetrical magnetic linkage between the stator windings. The aim of this paper is to present a simulation model to investigate the effect of internal fault on the parallel path currents of a large synchronous generator using direct phase quantities. This model is based on a modified winding function approach where the machine inductances are calculated directly from the machine winding distribution using machine electrical parameters instead of the geometrical ones. The simulation results for different cases of internal faults in salient-pole and non-salient-pole synchronous machines have been obtained. Salient-pole synchronous generator has wave winding distribution while the non-salient-pole generator has lap winding arrangement. Due to different stator winding arrangements, the two machines have been simulated individually. By using the simulated fault data, a suitable numerical protection scheme for synchronous generators can be developed.

]]> 10.1504/IJPEC.2012.044288 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 111 - 126 Amrita Sinha; D.N. Vishwakarma; R.K. Srivastava Department of Electrical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221005, India. ' Department of Electrical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221005, India. ' Department of Electrical Engineering, Institute of Technology, Banaras Hindu University, Varanasi-221005, India internal faults synchronous generators simulation modified winding function parallel windings modelling stator windings numerical protection. 2011-12-19T23:20:50-05:00 3 1/2 111 126 2011-12-19T23:20:50-05:00 http://www.inderscience.com/link.php?id=44301 As a result of the electronic revolution in power electronics technology, a number of control devices under the term flexible AC transmission system (FACTS) have been proposed and implemented and this has led to improvements in efficient energy transfer, reduced looses and maximised use of existing infrastructure. FACTS controllers have been designed using high power electronic system components, in particular the voltage source converter (VSC) that permits quick response to control inputs. In this paper, a model is proposed for a multi-level, 48-pulse VSC for a FACTS system. The proposed model is studied in terms of both reactive power compensation and harmonic distortion. The model and control algorithms are simulated in MATLAB (Simulink). In order to identify the best location (the weakest bus) of the FACTS controller, a study is conducted on 14-bus IEEE reliability test system using some static voltages stability indices found in the literature. The results are presented and discussed. Weakest bus identification for optimal location for FACTS systems in multi-machine power network
Mohamed K. Jalboub; H.S. Rajamani; J.C. Readle; Read A. Abd-Alhameed; Abdelbaset M. Ihbal
International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 127 - 142
As a result of the electronic revolution in power electronics technology, a number of control devices under the term flexible AC transmission system (FACTS) have been proposed and implemented and this has led to improvements in efficient energy transfer, reduced looses and maximised use of existing infrastructure. FACTS controllers have been designed using high power electronic system components, in particular the voltage source converter (VSC) that permits quick response to control inputs. In this paper, a model is proposed for a multi-level, 48-pulse VSC for a FACTS system. The proposed model is studied in terms of both reactive power compensation and harmonic distortion. The model and control algorithms are simulated in MATLAB (Simulink). In order to identify the best location (the weakest bus) of the FACTS controller, a study is conducted on 14-bus IEEE reliability test system using some static voltages stability indices found in the literature. The results are presented and discussed.

]]> 10.1504/IJPEC.2012.044301 International Journal of Power and Energy Conversion, Vol. 3, No. 1/2 (2012) pp. 127 - 142 Mohamed K. Jalboub; H.S. Rajamani; J.C. Readle; Read A. Abd-Alhameed; Abdelbaset M. Ihbal School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK. ' School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK. ' School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK. ' School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK. ' School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK two-level VSC flexible AC transmission systems FACTS harmonic distribution reactive compensation stability indices weak buses power efficiency energy efficiency Matlab power electronics voltage source converters. 2011-12-19T23:20:50-05:00 3 1/2 127 142 2011-12-19T23:20:50-05:00