RE&PQJ-6 ISSN 2172-038X

Renewable Energy & Power Quality Journal, Vol. 1, No.6, March 2008


RE&PQJ-6 Index




IS1 Renewable Energy - Panacea for Climate Change?. Ozdemir Göl. University of South Australia. Adelaide. Australia

IS1 two sheets summary

IS2 Improving the operation and maintenance of wind farms: determination of wind turbine performance
Andrés Llombart-Estopiñan. CIRCE Fundation; Department of Electrical Engineering. Zaragoza University. Spain

IS2 two sheets summary

IS4 Unified loss theory and its application on Low Voltage network
András Dán, David Raisz. Depatment of Electrical Power Engineering. Budapest University of Technology and Economics. Hungary.

IS4 two sheets summary


200 High Voltage of two batteries-two five-levels NPC voltages sources inverters cascade. Application to the DSIM drive
S.Arezki(1), E.M.Berkouk(2)
(1).Université des sciences et de la Technologie Houari Boumediene. Alger
(2). Laboratoire de commande des processus.Ecole National Polytecnicque d'Alger

212 A minimal-order observed based control method for PV generator to reduce frequency deviations of power system
Tomonobu Senjyu(1), Manoj Datta(1), Atsushi Yons(1), Toshihisa Funabashi(2), Chul-Haw Kim(3)
(1). Department of Electrical and Electronics Engineering. University of Ryukyus. Japan
(2). Meidensha Corporation. Japan
(3). School of Electrical and Computer Engineering, Sungkyunkwan University, Korea

In this paper, a minimal-order observer based control method is proposed. Here, the PV power is controlled according to load variation to minimize the frequency deviation. Load power and diesel power is estimated by a minimal order observer successfully. From the estimated load power, load variation index is calculated. A low-pass filter is used to produce PV base power from maximum PV power. Then, PV base power is added with the load variation index to generate the command PV power. The proposed method is compared with the method where Maximum Power Point Tracking (MPPT) control and found superior in performance.

212 two sheets summary

213 PV output power fluctuations smoothing and optimum capacity of energy storage system for PV power generator
Tomonobu Senjyu(1), Manoj Datta(1), Atsushi Yona(1), Toshihisa Funabashi(2), Chul-Hwan Kim(3)
(1).Department of Electrical and Electronics Engineering. University of Ryukyus. Japan
(2).Meidensha Corporation. Japan
(3).School of Electrical and Computer Engineering, Sungkyunkwan University, Korea

In this paper, an Energy Storage System (ESS) based control method is proposed to reduce the PV output power fluctuations. The ESS control model introduced here will maintain the energy storage ratio near 50%. This will increase the life time of the ESS as well as will decrease the maintenance cost. A local search algorithm is also provided with this ESS control model to search the optimal capacity of the ESS required for smoothing the PV output power fluctuations and to find the minimum capital cost. A cost comparison is shown to realize the performance of the search algorithm.

213 two sheets summary

215 Dynamic optimization of a 2-DOF pseudo-equatorial tracking in virtual prototyping concept
C.Alexandru, M. Comsit, P.Alexandru
Product Design and Robotics Department. University "Transilvania" of Brasov. Rumania

The key word for the design process of the tracking systems is the energetic efficiency. Using the tracking system, the panel follows the sun and increase the collected energy, but the driving motors consume a part of this energy. In paper, we evaluate a strategy for the dynamic optimization of the tracking systems. The main task in optimization is to maximize the energetic gain by increasing the incoming solar radiation, and minimizing the energy consumption for tracking. This study is performed by developing the virtual prototype of the tracking system, which is a control loop composed by the multibody mechanical model connected with the dynamic model of the actuators, and with the controller model.

215 two sheets summary

216 Effect of large scale wind farms on the Egyptian power system dynamics
M.EL-Sayed(1), Effat Moussa(2)
(1). Electrical Power Engineering. Dept. Cairo University
(2). Egyptian Electricity Holding Company.

In recent years wind energy has become an important source of clean electrical generation. Therefore, the penetration of wind turbines in electrical power systems will be increasing and then they may begin to influence overall power system behavior, making it impossible to run a power system by only controlling large scale power plant. This foreseen expansion will result in many technical issues which must be dealt with in order to guarantee that the quality of the utility power is not affected. A file
In this paper aggregated wind farm modeling is presented to investigate the effect of wind farms of different sizes on the Egyptian power system dynamics. The wind farm is aggregated into minimal set of equivalent wind generator models combining all turbines with the same mechanical nature frequency into single equivalent turbine. Power system dynamics simulation software is used to study the impact of increasing wind turbine penetration on system performance. The proposes technique presented in [1] to estimate the reduction in conventional electric capacity in presence of Wind Turbine Generators is applied while selecting the proposed wind farm size.. The result shows that the Egyptian system can withstands wind farms size up to 900 MW.

217 The strategic implantation of energy management in a multinational enterprise
J. González de la Viuda(1), V. Romero Arauzo(2)
(1). Department of electromechanical engineering. University of Burgos. Spain
(2). L' Oreal, Capillary Products. Spain

218 Comparitive study of sensible and latent heat storage systems integrated with solar water heating unit
S.A.Vijay Padmaraju(1), M.Viginesh(1), N.Nallusamy(2)
(1).Department of Mechanical Engineering. Sri Venkateswara College of Engineering. India
(2). Head of the Department of Automobile Engineering. India

This work was undertaken to study the feasibility of storing solar energy using phase change materials and utilizing it to heat water for nighttime usage. This system has a solar water heater and a heat storage system with PCM. The solar water heater supplies hot water during the day. The storage unit stores the heat in PCM's and supplies hot water during the night. It utilizes small Aluminium cylinders filled with paraffin and integrated with a solar collector. The performance of this system is compared with conventional system and their conclusions are presented.

220 Electromagnetic interferences in inverter-fed induction motor drives
Stanislav Bartos, Ivo Dolezel, Jakub Necesany, Jiri Skramlik, Viktor Valouch
Institute of Thermomechanics ASCR. Praha. Czech Republic

The paper deals with the numerical modeling of a pulse-width modulated voltage inverter-fed induction motor drive for the common and differential current modes. The proposed model of the drive respects the influence of the feeding cable described by the lumped or distributed parameters. The theoretical analysis is supplemented by results of relevant simulations and experiments. Evaluated are also the frequency characteristics of selected parts of the system and their contributions to its resultant harmonic spectra.

220 two sheets summary

222 Weighting function integrated in grid-interfacing converters for unbalanced voltage correction
Fei Wang, Jorge L. Duarte, Marcel A.M. Hendrix
Department of Electrical Engineering. Eindhoven University of Technology. The Netherland.

A weighting function for voltage unbalance correction is proposed to be integrated into the control of distributed grid-interfacing systems. The correction action can help decrease the negative-sequence voltage at the point of connection with the grid. Based on the voltage unbalance factor, the interfacing converter delivers a small amount of negative-sequence current to the grid and helps correcting the negative-sequence voltage. Although the reduced amplitudes contributed by each individual DG system are small compared to the total negative-sequence component, many DG modules can collectively achieve substantial results. As an example, a three-phase grid-interfacing converter is employed to integrate this function.

222 two sheets summary

223 A suitable power transfer control system for interconnection converter of DC microgrids
Mishel Mahmoodi, Reza Noroozian, Gevorg B. Gharehpetian, Mehrdad Abedi
Electrical Engineering Dept. Amirkabir University of Technology. Tehran. Iran

223 two sheets summary

224 Intelligent sun-tracking system for efficiency maximization of photovoltaic energy production
João M.G. Figueiredo(1), José M.G.Sá da Costa(2)
(1). CEM-IDMEC. Universidade Evora. Mechatronics Group. Portugal
(2). IDMEC-IST- Technical University Lisbon, Portugal

225 Implementation of a bang-bang strategy for PV system connected to the grid
B. Efker(1), A. Martinez(2), H.M.Reddy(3)
(1). Siemens AG- Osnabrück, Germany
(2). Ecole d´Ingénieurs en Génie des Systèmes Industriels (EIGSI), La Rochelle, France
(3). School of Engineering, University of the South Pacificic, Suva, Fiji Islands

This paper presents a bang-bang strategy for PV system connected to the grid. A string PV system coupled to a single stage inverter is described. The inverter presented in this paper utilizes higher order DC filtering and is made of a single stage topology utilizing PI regulators to control the Maximum Power Point (MPP). Additional PI regulators are employed to minimize the Total Harmonic Distortion (THD) to the minimum. The inverter designed meets all relevant standards requirements.

225 two sheets summary

228 Energy quality in voltage, current and power signals
Tomás Yebra, Vicente Fuster
Instituto de Tecnología Eléctrica. Parque Tecnológico de Valencia. Spain

228 two sheets summary

229 Model based predictive current control of an asynchronous six-phase motor drive
R. Gregor(1), F. Barrero(1), M.J. Durán(2), M.R. Arahal(1), S. Toral(1)
(1). Electronic & System amd Automation Engineering Departments. E.S.I.I. University of Seville. Spain
(2). Electrical Engineering Department. E.S.I.I. University of Málaga. Spain

230 Realization of an asynchronous six-phase induction motor drive test-rig
R. Gregor(1), F. Barrero(1), S. Toral(1), M.J. Durán(2)
(1). Electronic Engineering Departments. E.S.I. University of Seville. Spain
(2). Electrical Engineering Department. E.S.I.I. University of Málaga. Spain

235 Quality of electricity supply as a service
Erwin Seršen(1), Jože Voršic(2)
(1). The Energy Agency of the Republic of Slovenia, Slovenija
(2). Faculty of Electrical Engineering and Computer Science. University of Maribor, Slovenija.

Electricity supply has nowadays become a part of every day life and is a service expected by electricity consumers. Their expectations rely on the availability of electricity whenever needed and on a safe and satisfactory operation of all connected electrical devices.
The expenses of electricity quality are in the time of open market very important to the consumers and especially to the industry. They in fact signify an additional value which can be ensured to the consumers by the suppliers in order to increase their productivity and reliability of the production process.
In order to carry out economic regulation of network charge, the Energy Agency of the Republic of Slovenia (Slovenian regulator) monitors quality of electricity supply. The Agency monitors the parameters of quality electricity supply with the intention of permanently increasing its level. At the other side on have to know where the disturbances are coming.

236 Fault Diagnosis of tin oxide gas sensor using energy barrier and ART-2 neural network
In-Soo Lee(1), Chang-Hyun Shim(2)
(1). School of Electronics and Electrical Engineering, Sangju National University. Korea
(2). Purenanotech Co. Ltd Daegu. Korea

The authors propose a method of fault diagnosis for tin oxide gas sensors using energy barriers at the contacting surfaces of the particles of tin oxide film and ART-2 NN (adaptive resonance theory 2 neural network) with uneven vigilance parameters. We diagnosed tin oxide gas sensors upon exposure to oil vapor, silicon vapor, and high humidity. The sensor feature for diagnosis was an energy barrier between particles extracted by temperature-simulated conductance measurement. The feature was manipulated by an ART-2 neural network and the performance was finally evaluated with real n-C4H10 gas. This method proves to be helpful to diagnose a fault that was typically generated by oil vapor, silicon vapor, and high humidity.

241 Electromagnetic interference at the mains ports of an equipment
Mircea Ion Buzdugan, Horia Balan, Emil E. Simion, Tudor Ion Buzdugan
Technical University of Cluj- Napoca, Romania
Distribution line hardware can generate radio-frequency interference (RFI). Such interference can impact the AM and FM bands as well as VHF television broadcasts.

The paper presents an electromagnetic interference problem, due to the proximity of two AM radio broadcasting stations which injected especially common mode conducted emissions over the maximal limits specified by the national regulations in the public low voltage mains network.
These emissions determined the malfunction of the gas heating centrals Themaclassic Saunier Duval installed in the area. The problem was solved by the retro fitting of an extra EMI filter for the mains network, as presented in the paper.

242 Energy efficiency modelling and estimation in petroleum refining industry- A comparison using physical data
A. Azadeh, S.F. Ghaderi, S.M. Asadzadeh
Department of Industrial Engineering, Faculty of Engineering, University of Tehran. Iran

In this paper, energy efficiency in petroleum refining industry has been analyzed using the non-parametric data envelopment analysis approach with physical data. The proposed model for evaluation of energy efficiency does not require energy data in the operational levels for considering the structural effects. The average weighted boiling point of refined products is used as structural indicator in the proposed model. Also, data envelopment analysis (DEA) is used as a sensitivity analysis tool for determination of the potentials and means of energy consumption improvement and optimization. The unique feature of this study is based on the utilization of DEA for separation of structural effects from other effects which are referred to as activity and intensity effects. The proposed model is also verified and validated by principle component analysis (PCA) and non-parametric Spearman correlation technique.

244 Predictive-integral current controller for active-and reactive-powercontrol of wind generators
Pedro Roncero-Sánchez(1), Vicente Feliu(1), Aurelio García-Cerrada(2)
(1). Department of Electrical, Electronic, Control Engineering and Communications. E.T.S.I.I. University of Castilla- La Mancha. Spain
(2). Department of Electronics and Control Engineering. Ingeniería ICAI. Universidad Pontificia Comillas. Spain

This paper deals with the design of a predictive-integral current controller for wind generators connected to the grid. The goal is to achieve a decoupled control of d- and q-axes current components at the connection point, which results in a decoupled control of the active and the reactive power exchanged between the generator and the grid. Furthermore, the control system is designed to achieve a deadbeat closed-loop system. The robustness of the closed-loop dynamic response and the active and reactive-power coupling when system-modelling errors exist are studied. Simulation and experimental results are presented to validate the main contributions.

244 two sheets summary

245 Trigeneration systems with fuel cells
J.I. San Martín(1), I. Zamora(2), J.J. San Martín(1), V. Aperribay(1), P. Eguía(2)
(1). Escuela Universitaria de Ingeniería Técnica Industrial de Eibar. University of The Basque Country. Spain
(2). Escuela Técnica Superior de Ingeniería de Bilbao. University of The Basque Country. Spain

Trigeneration systems include those processes of production and simultaneous use of electricity, heat and cold, from a single fuel source. The simultaneous use of energy allows obtaining high levels of overall energy efficiency, lower emissions, security of supply, as well as lower losses and investments in networks.
The context of implementation of trigeneration ranges from low voltage distributed generation to the electric microgrid prototypes currently under research. In this last environment, the work is mainly focused in the following power generation technologies: Fuel Cells, Microturbines, Stirling Engines, Small Wind Turbines, and Photovoltaic plants.
This paper focuses on those research proposals that are currently being developed using fuel cells as base technology for trigeneration.

245 two sheets summary

246 A device for improving the immunity of ac contactors during voltage dips
P. Andrada, J.I. Perat, G. Navarro
Universitat Politecnica de Catalunya (UPC) Spain
This paper describes an electronic device that enables AC contactors to ride through power quality disturbances. The proposed device is connected to the contactor coil and consists of a power conversion excitation and hold-in circuit, a control circuit, an immunity circuit and a shutdown circuit. It does not disturb contactor operation, is easy to use and can be built from cheap, commercially available components. Experimental tests have demonstrated the effectiveness of the proposed electronic device for improving the immunity of AC contactors during power quality disturbances, particularly voltage dips.

246 two sheets summary

247 Wind turbine permanent magnet synchronous generator magnetic field study
B. Ghita, A.L.; Chirila, I; D. Deaconu; D.I. Ilina
Department of Electrical Engineering. University Politehnica of Bucharest. Romania

The paper shows a 2D finite element optimization method for a wind turbine permanent magnet synchronous generator (PMSG) transverse geometry. Keeping the same rotor diameter the generator's magnetic flux is maximized by changing the permanent magnets and rotoric slot opening dimensions. The studies show that for certain values of these dimensions the magnetic flux (flux linkage and mutual flux) has maximum values.

247 two sheets summary

248 Investigation methods for power quality problems in large scale LV network
P.R. Wilczek, M.C. Benhabid, J.A.A. Myrzik, J.L. Duarte
Department of Electrical Engineering, Eindhoven University of Technology. The Netherlands

249 Wireless module of localization and control for security
J.Luna Rodriguez(1), V. Barranco López(2), D. Bullejos Martín(2),A Sabariego Hernández(1)
(1). Department of Architecture of Computers, Electronic Technology and Electronic. E.P.S. Córdoba University. Spain
(2). Department of Electrical Engineering. E.P.S. Córdoba University. Spain

250 Energy Savings by means of energy efficient electric motors
S. Corino, E. Romero, L.F. Mantilla
Department of Electrical Engineering and Energy. E.T.S.I.I. y T. University of Cantabria. Spain

250 two sheets summary

252 Design and implementation of an efficient hybrid system for electricity production
Luís P.M. Fernandes(1), João M.G. Figueiredo(2)
(1). CEM, Universidade Évora. Portugal
(2). IDMEC-IST- Technical University Lisbon. Portugal

255 Effects of interfacial oxide layer thickness and interface states on conversion efficiency of SnO2/ SiO2/Si(N) solar cells
D.Hocine, MS. Belkaid
Faculty of Electrical and Computer Engineering. The University Mouloud Mammeri. Algiers

In this paper, we studied the effects of interfacial oxide layer thickness and interface state density on the open circuit voltage and efficiency of the SnO2/SiO2/Si (N) solar cells. The results obtained by numerical simulation using Matlab programs are presented and discussed. The SnO2/SiO2/Si (N) solar cells, in which the interfacial oxide layer thickness is optimized to 21 A°, have an average open circuit voltage of 0.62 V and a short circuit current of 36 mA/cm². The calculated conversion efficiency of the cells can be as high as 17.5 %.

255 two sheets summary

256 Optimal location and size of SVC and TCSC for multi-objetive static voltage stability enhancement
R. Benabid(1), M. Boudour(2)
(1). Nuclear Research Center of Birine. Algiers
(2). Department of Electrical Engineering. University of Sciences & Technology Houari Boumediene. Algiers

A Non-dominated Sorting Particle Swarm Optimization (NSPSO) is used to solve a mixed continuous-discreet Multi-objective optimization problem witch consist of optimal location and size of Static Var Compensators (SVC) and Thyristor Controlled Series Capacitors (TCSC) in order to maximize Static Voltage Stability Margin (SVSM), reduce power losses (PL) and minimize load Voltage Deviations (VD). While finding the optimal location, thermal limits for the lines and voltage limits for the buses are taken as security constraints. The optimization is performed considering two and three objectives for various combinations of FACTS. Simulations are performed on IEEE 14 test system for optimal location and size of FACTS devices. The obtained results are very encouraging and reveal the capability of the method to generate well-distributed non-dominated Pareto front.

257 Comparison of fault ride through characteristics of VSI current controllers
J.F. Sanz, J. Sallán, M.A. Alonso
CIRCE Foundation and Electrical Engineering Department of the University of Zaragoza. Spain

The paper compares the voltage sag ride-through response of three current control methods applied to a voltage source inverter (VSI): traditional hysteresis, constant frequency (Dead-Beat) and hysteresis vector control with predictive algorithm.

In the analysis of these control methods it has been taken into account: response speed, current error deviation and total harmonic distortion during the sag, finding out the most suitable, depending on the required characteristics.

258 Power quality permanent monitoring systems in Romania
Carmen Stanescu(1), Jakob Widmer(2), Sorin Cristian Pispiris(1)
(1). Company Transelectrica. Romania
(2). Landis+Gyr. Switzerland

258 two sheets summary

260 Single phase AC power load profile emulator
Y. Thiaux, J. Seigneurbieux, B. Multon, H. Ben Ahmed, D. Miller
SATIE/SETE ENS de Cachan. Antenne de Bretagne. France

This paper deals with the realization and design of a consumption profile emulator intended for the validation of different element energy models of a stand-alone wind and photovoltaic system associated with electrochemical energy storage. The emulator is made of two back-to-back PWM converters connected to the grid. It is designed to vary active power but in a near future it will also be used to load simulation with reactive power. Energy models are then inserted in a sizing optimization algorithm in order to minimize the Global Energy Requirement (GER) of the whole system.

262 New control strategy to improve power quality using a hybrid power filter
S.P. Litrán, P. Salmerón, R.S. Herrera, J.R. Vázquez
Department of Electrical Engineering . Escuela Politécnica Superior, University of Huelva. Spain

A new control algorithm for a hybrid power filter constituted by a series active filter and a passive filter connected in parallel with the load is proposed. The new control strategy is based on the dual formulation of the vectorial theory of electric power, so that the signal injected by the active filter is able to compensate the reactive power and the harmonics of the load current. To verify the developed theoretical analysis, the control strategy was verified by means of an experimental prototype. The results to verify the effectiveness of the proposed control algorithm are presented.

262 two sheets summary

265 Current control of distributed generation power inverters for losses reduction in the distribution network
E.Belenguer, Héctor Beltrán, Néstor Aparicio, E. Pérez
Department of Industrial Engineering and Design. Universitat Jaume I. Spain

The main objective of the paper is to evaluate the power losses reduction that can be achieved in a low voltage distribution network when the inverters associated to the distributed generation are used as active power filters to compensate the non active currents produced by inductive and unbalanced loads. For that purpose, a hysteresis current control has been proposed and implemented. A real distribution three-phase four-wire network has been simulated considering a large penetration of distributed generation. Power losses and the efficiency of the network have been quantified for different compensation cases.

266 Energy storage device as a part of electric energy production system based on renewable energy sources
Sebastijan Seme, Gorazd Štumberger, Jože Voršic
University of Maribor, Faculty of Electrical Engineering and Computer Science. Slovenia

This work deals whit an energy storage device as a part of electric energy production system based on renewable energy sources. The system supplies given load with known load diagram. Operational diagrams of individual units in the system are determined in an optimization procedure. The optimization goal is to supply given load with minimal use of conventional energy delivered from electric grid. Optimization is performed by a stochastic search algorithm called Differential Evolution for the system consisting of the solar power plant, wind turbine unit, flow battery, load and electric grid. The optimization input data are given weather forecasting and forecasted load diagram.

266 two sheets summary

267 Evaluation of excessive transmission line losses caused by unbalanced and nonlinear three-phase loads
Klemen Deželak, Gorazd Štumberger
University of Maribor, Faculty of Electrical Engineering and Computer Science. Slovenia

This work evaluates excessive transmission line losses caused by unbalanced and nonlinear three-phase loads. The orthogonal decomposition of currents is applied in order to determine current component indispensable for energy transmission and current components that do not contribute to the energy transmission. The last ones cause excessive losses in the transmission lines. It is shown that the excessive transmission losses increase with the inverse ration of squared generalized power factor. According to the presented results, in the case of unbalanced nonlinear loads, the excessive transmission losses can reach almost the same value as the transmission losses due to the linear and balanced loads.

267 two sheets summary

268 Experimental study of a PEM reversible fuel cell
S. Rabih, O. Rallieres, C. Turpin, S. Astier
University of Toulouse- Laboratory LAPLACE. France

269 Biogas situation and development in Thai Swine Farm
Wongkot Wongsapai(1), Poon Thienburanathum(2), Prasert Rerkkriengkrai(3)
(1). Depatment of Mechanical Engineering.Faculty of Engineering, Chiang Mai University. Thailand
(2). Department of Civil Engineering. Chiang Mai University, Chiang Mai. Thailand
(3).Energy Research and Development Institute, Chiang Mai University. Thailand

The biogas technology in Thailand has been developed and adopted in swine farm industry. The objectives of the biogas development are based on three problems; (i) to reduce the appalling odor, (ii) to treat the wastewater, (iii) and to produce the biogas which is known as a renewable energy sources from the anaerobic digestion wastewater treatment processes. The biogas situation including the technology development which are mainly used the upflow anaerobic sludge blanket (UASB) bioreactor system, was discussed. From the results, we found that 11.6 million cubic meters of biogas per year would be produced which gas then be used for various proposes; e.g. electricity generation, LPG or fuel oil substitution in boiler.

271 Biodiesel technology and management from used cooking oil in Thailand rural areas
Pongsiri Jaruyanon(1), Wongkot Wongsapai(2)
(1). Faculty of Engineering and Industrial Technology, Silpakorn University, Nakorn Prathom, Thailand
(2). Faculty of Engineering, Chiang Mai University, Chiang Mai, Thailand

The small-scale biodiesel production unit from used cooking oil have been design and constructed for use in rural areas in Nakorn Sawan province, Thailand. In this paper, used cooking oil potential quantity has been surveyed and found that there are 1.3 million litres of used cooking oil per year. The used cooking oil can turn to biodiesel using transesterification processes which converted triglycerines to biodiesel by mixing with methanol to be fatty acid methyl esters. Biodiesel can be used for various proposes; e.g. diesel substitution, agricultural machines. This paper also discussed management and flows of biodiesel from the sources to end-users.

272 Multichannel online quality and efficiency power network diagnostic according to IEC standards
Richárd Bátorfi
Department of Electrical and Electronic Engineering, University of Miskolc. Hungary

273 Digital filter simulation for development of digital flickermeter
Attila Unhauzer(1), Angéla Váradi(2)
(1).Department of Electrical and Electronic Engineering, University of Miskolc. Hungary
(2). Department of Electrical and Electronic Engineering. University of Miskolc. Hungary

274 A survey on voltage dip events in power systems
V. Barrera-Núñez, J. Meléndez-Frigola, S. Herraiz-Jaramillo
Institute of Informatics and Applications of the University of Girona, Spain

A general view of voltage dip analysis is presented in this paper. The objectives to perform voltage dip analysis, activities inside of this analysis and methodological aspects are described from a data mining perspective. Basic data mining principles were taken as the basis to identify similar steps in power quality works involving classification and knowledge discovery tasks. This paper is centred in voltage dip event diagnosis in order to reduce the study and focus the analysis.

Power quality data is generated at several locations in local utility's service territory, asynchronously during long periods of time. This information is continuously monitored and registered, causing a great volume of data. Consequently, the amount of data is increasing daily, due to the advances in the data storage technologies too. The end-user has a large amount of data to assess and reduce the power quality problems. The technologies to transform in a short time raw data in knowledge or answers have been few developed. Hence, the new goal of monitoring systems is to transform automatically this huge amount of data into useful knowledge in order to assist the management of the network.

274 two sheets summary

275 Multi-phase generators viability for offshore wind farms with HVDC transmission
M.J. Duran(1), F. Barrero(2), S. Toral(2), M. Arahal(2), R. Gregor(2), R. Marfil(1)
(1). Electrical Engineering Department, School of Engineering, University of Málaga (Spain)
(2). Electronic & Automatic Engineering Department, School of Engineering, University of Seville (Spain).

277 Wind generation and power system interaction analysis using probabilistic techniques
Marco Ortiz, Juan Rios, Manuel Acosta
Transmission Planning Department. CVG EDELCA. Venezuela

Energy power from renewable sources, especially wind turbine generators, are being considered as an important generation alternative in the electrical power systems around the world due to their non contaminant nature and low environmental effects. In particular, the power supplied by wind generators is widely random; therefore a probabilistic approach during planning seems much more appropriate than the deterministic approach actually used in the electrical utilities. This paper presents a methodology that allows the application of probabilistic analysis, thru the use of programming tools and the development random wind speed generator, to be used in the load flow planning studies.

278 A simple neural network solar tracker for optimizing conversion efficiency in off-grid solar generators
Marius Alexandru Panait, T.Tudorache
Polytecnic University of Bucharest. Romania

278 two sheets summary

279 Harmonic source identification of a distributed generator, and compensation the voltage change caused by changing generation
Bálint Hartmann, András Dán
Department of Electric Power Engineering Budapest University of Technology and Economics. Hungary

279 two sheets summary

280 Contemporary approach to determination of magnetic induction in wind generator air gap
A. Elez(1), B. Tomicic(2), B. Takac(1)
(1). Koncar- Electric Engineering Institute Inc. Zagreb. Croatia
(2). Koncar- Generators and Motor Inc. Zagreb. Croatia

281 Improving the incremental conductance control method of a solar energy conversion system
Janine Kouta(1), Ali El-Ali(1), Nazih Moubayed(1), Rachid Outbib(2)
(1). Department of Electrical and Electronic Engineering, Lebanese University, Tripoli. Lebanon
(2). Laboratory of Sciences in Information and Systems (LSIS), Aix-Marseille III University, Marseille. France

The sun is at the origin of the quasi-totality of the sources of energies used by the humanity for its food, domestic and industrial needs. In this paper, after presentation of the studied system, the conversion from solar energy to electrical one is treated. The 'incremental conductance' method is used to maximize the output power of a solar panel. This method had been improved by using the averaging strategy of the chopper duty cycle. The time responce is reduced, but, power ripples appears. To eliminate them, the delta adaptative strategy was applied.

281 two sheets summary

282 Analysis of a single phase inverter for photovoltaic systems operating in a weak electric grid
Gorazd Štumberger, Sebastijan Seme, Klemen Deželak, Andrej Hanžic, Jože Voršic
University of Maribor, Faculty of Electrical Engineering and Computer Science. Slovenia

Single-phase inverters for photovoltaic systems are normally analyzed when they are connected to the strong electric grid with low impedance. This work focuses on analysis of a single-phase inverter operating in a weak electric grid with relatively high impedance. Presented are experimentally determined results for the inverter's efficiency, voltage and current total harmonic distortion and power factor. The results presented show substantial contents of sub harmonic components in the inverter's output current.

282 two sheets summary

283 Numerical interpolation methods applied in electromagnetic interference problems
Dan D. Micu(1), Andrei Ceclan(1), Iosif Lingvay(2), Emil Simion(1)
1. Department of Electrical Engineering, Technical University of Cluj- Napoca. Romania
2. INCDIE ICPE- Cercetari Avansate, ICPE SA Bucuresti. Romania

In the paper are evaluated the induced potential in a gas pipeline based on the subdivision of the zone of influence AC power lines / electric traction line / gas pipeline, in a relatively great number of sections in order to be able to determine voltages at many positions along the gas pipeline. Is presented a practical case from Cluj (Romania), of subdivision of the zone of influence in sections and is created a special interpolation algorithm for the precise calculation of the induced voltages values in different points on the pipeline taking into account the measured data. Is observed that the interpolation spline function with linear end conditions is more precise than the linear interpolation polynom but the presented MathCad algorithm gives us the correct data if the interval of the influence zone is increasing. The interpolation functions, linear and spline, do a great job in fitting a continuous link function between magnetic permeability and induced electrical currents.

284 Multi-level representation for the control design of a super capacitor storage system for a microgrid connected application
Peng LI(1,2), Philippe Degobert(2), Bruno François(1), Benoît Robyns(3)
(1). Ecole Centrale de Lille (L2EP). France
(2). Ecole National Supérieure d' Arts et Métiers. Lille. France
(3). Hautes Etudes d' Ingénieur. Lille. France

In this paper an average multi-level representation of power electronic converters is used to design a dynamic model of a Super Capacitor Bank for a microgrid application. A dedicated multi-level modelling is designed to quantify energy variations in storage elements (super capacitors, DC bus) and various losses. We demonstrate that this model is sufficient to design the control system of the entire power storage system, meanwhile the super capacitors, the chopper and the grid connected converter. The proposed global model is simulated with the help of Matlab-SimulinkTM by considering two units of 48V 144F super capacitor modules.

284 two sheets summary

285 Unified power quality conditioner (UPQC) with voltage dips and over-voltages compensation capability
Victor M. Moreno(1), Alberto Pigazo(1), Marco Liserre(2), Antonio Dell' Aquila(2)
(1). Department of Electronic and Computers. University of Santander. Spain
(2). Dipartimento di Elettrotecnica ed Elettronica.Politecnico di Bari. Italy

Unified power quality conditioners (UPQCs) allow the mitigation of voltage and current disturbances that could affect sensitive electrical loads while compensating the load reactive power. Diverse control techniques have been proposed to evaluate the instantaneous output voltage of the series active power filter of the UPQC but, in most cases, these controllers only can compensate a kind of voltage disturbance.

This paper proposes a new digital controller for UPQCs which allows the load current harmonics and reactive power to be compensated at the grid side while avoiding the effect of voltage dips, over-voltages and voltage harmonics on the local loads. The controller characteristics can be established on-line without changing its basic structure. The performance of the proposed controller has been evaluated through simulation tests.

286 Power systems disturbance classification using modular neural networks with multilayers experts
R.M.Magalhães, C.K.S. Santos, J.D. Melo, Medeiros, A.D. Dória Neto
Intelligent Systems Laboratory, Federal University of Rio Grande do Norte, Natal, Brasil.

287 Wind tunnel assessment of small direct drive wind turbines with permanent magnets synchronous generators
Mihai Predescu(1), Andrei Bejinariu(1), Adrian Nedelcu(1), Octavian Mitroi(1), Catalin Nae(2), Mihai.Victor Pricop(2), Aurelian Craciunescu(3)
1. ICPE S.A.- SICE Centre. Romania
2. INCAS. Romania
Universitatea Politehnica Bucuresti. Romania

288 The occurrence of faults in permanent magnet synchronous motor drives an its effects on the power supply quality
J. O. Estima, A.J. Marques Cardoso
University of Coimbra. FCTU/IT. Portugal

The non-sinusoidal current drawn by variable speed drives has increase the concern about its effects on the distribution system power quality. On the other hand, electrical drives based on permanent magnet synchronous motors have become serious competitors against induction motors drives. This paper presents a study of the effects on the power supply quality due to the occurrence of faults in a permanent magnet synchronous motor drive. Only single open-circuit faults in the inverter are considered.

288 two sheets summary

289 Graphic tools for analysing the influence of noise and aperiodic components in the performance of digital filters: a case study
J. Lázaro(1), M.A. Zorrozua(2), J.F. Miñambres(2), M.I. Sánchez(1), B. Larrea(1), I. Antiza(3)
(1). Department of Applied Mathematics. E.T.S.I.Basque Country University. Spain
(2).Department of Electrical Engineering. E.T.S.I. Basque Country University. Spain
(3). GE Multilin. Zamudio. Spain

An accurate phasor estimation is an important task for a correct operation of digital protections. The performance of these devices is affected by the presence of aperiodic components in electrical signals. In addition, their stability is heavily conditioned by the distortion resulting from the noise inherent to signal processing.

Usually, numerical performance indices are used to measure the accuracy of a proposed method. In order to ease the analysis and comparison of different digital filters, a new set of graphic tools is presented in this paper.

A case study is presented with three different filtering algorithms developed for protection relaying.

289 two sheets summary

290 Dynanic power flow tool development for low voltage networks analysis with penetration level of distributed generation
A.Milo(1), A. Martinez(1), M. Rodriguez(2), A. Goikoetchea(2)
(1). Department of Control Engineering. IKERLAN, Technological Research Centre. Spain
(2). Faculty of Engineering, University of Mondragon. Spain

This article presents the development of a power flow tool to analyse the impact of the integration of distributed generation on low voltage distribution networks. The work has been implemented in MATLAB-SIMULINK environment. The developed tool can be used in radial or weakly meshed 3-phase networks with the presence of distributed generation. The voltage and power magnitudes of selected nodes can vary over time allowing a dynamic power flow analysis.

291 Bond graph model of a PEM fuel cell stack
S. Rabih, C. Turpin, S. Astier
University of Toulouse - Laboratory LAPLACE Site ENSEEIHT. France

292 A new modulation approach to decrease total harmonic distortion of the SPWM voltage waveform using genetic optimization technique
N. Tutkun
Department of Electrical & Electronic Eng. Faculty of Eng. Karaelmas University. Turkey

293 Reduction in induction motor heating fed by a new PWM technique: results obtained in laboratory experiments
M.J. Meco-Gutiérrez(1), A. Ruiz González(1), F. Vargas-Merino(1), J.R. Heredia-Larrubia(2)
(1). E.T.S. Ingenieros Industriales. Electric Engineering Department. Spain
(2). Electronic Technology Department. University of Málaga

This paper presents the laboratory results on heat produced in an induction motor stator when this is fed by a controlled inverter using a new PWM technique designed by the authors, compared to the heat produced in the same motor fed by more traditional PWM techniques. The technique designed by the authors has a clear advantage over the other traditional PWM techniques in terms of heating the motor. This is due to the lower content of harmonics.

295 An overview on renewable energy technologies for developing countries: the case of Guinea Bissau
C. Boccaletti(1), G. Fabbri(1), J. Marco(2), E. Santini(1)
(1). Department of Electrical Engineering. University of Rome "La Sapienza". Italy
(2). Department of Civil Engineering. University Polithecnique of Madrid. Spain

295 two sheets summary

296 Design of an electrical drive for motorized bicycles
C.Boccaletti, G. Duni, P. Petrucci, E. Santini
Department of Electrical Engineering. University of Rome "La Sapienza". Italy

296 two sheets summary

297 Modifyng modern power systems quality by integrating grid computing technology
R. Al-Khannak, B. Bitzer
South Westfhalia University of Applied Sciences. Germany

298 Association of PV, gas micro turbine and short term storage system to participate un frequency control
Herbreteau J.(1,4), Courtecuisse V.(1,2), Peng L.(1,3), Degobert Ph(1,4), Robyns B.(1,2), Francois B.(1,3)
(1). Laboratoire d´Electrotechnique et d´Electronique de Puissance de Lille. France
(2). Ecole des Hautes Etudes d´Ingénieur. Lille. France
(3). Ecole Centrale de Lille. France
(4). Ecole National Supérieure des Arts et Métiers. Lille. France

The goal of this work is to propose a supervision methodology for hybrid generation systems. This strategy must improve the grid insertion of renewable distributed generator (DG) by associating them with a short term storage and available decentralized generator (ADG). A fuzzy logic supervisor (FLS) is proposed to maintain a reference power and to contribute to frequency control with a hybrid generator (HG) based on photovoltaic arrays, gas micro turbine and supercapacitors. A detailed method to build this supervisor is proposed. The proposed fuzzy logic supervisor is compared with a basic supervision strategy The FLS gives a better storage management by reducing high and low saturation state, thus the HG can provide a more regular power reserve to contribute to the primary frequency control. The performance of this supervisor is shown with the help of simulations.

299 Modeling and implementation of renewable energy sources to distribution systems
Josef Tlusty(1), Viktor Valouch(2)
(1). Department of Power Engineering. Faculty of Electrical Engineering, CTU. Czech Republic
(2). Department of Electric Machines, Drives and Power Electronics/ Institute of Thermomechanics. Czech Republic

Today´s trends are tending to environmental friendly sources utilization. This reality is affecting electrical energy distribution systems, means new technical solution and bring new tasks to be solved. Within new projects in the future in supplying local areas, a Power Operation and Power Qua1ity Management System (POPQMS) must be developed. In order to model the parts of network with regulation programmable opened software in Matlab - DynaSolv was developed. DynaSolv can simulate multi-machine dynamics. The paper describes various principles of penetration synchronous machine type DGS into distribution network. This study provides possible complex analysis view on DGS stability issues, which can answer the possibility of connection.

300 Unit commitment and generation dispatch of a hydropower plant in a competitive electricity market
Juan I. Pérez, José R. Wilhelmi, Luis A. Arévalo
Departamento de Ingeniería Civil: Hidráulica y Energética. E.T.S.I. de Caminos, Canales y Puertos. Technical University of Madrid. Spain

This paper presents a novel approach based on dynamic programming to solve the short-term scheduling problem of a hydropower plant in a competitive electricity market. The solution of the problem provides both the optimal units status (on/off) and the optimal power output in each stage of the time period considered (from one day to one week). The power is considered as a nonlinear function of the water discharge and the reservoir volume; the dependence of the units and plant operating limits on the gross head, and the water discharged through the spillway have been also taken into account.

300 two sheets summary

302 Renewable energy supervision and real time production control in Spain
T. Domínguez(1), la Torre(1), G. Juberías(1), E. Prieto(2), R. Rivas(1), E. Ruiz(1)
(1). Dpto de Centro de Control Eléctrico (CECOEL). Red Eléctrica de España SA. Spain
(2). Dpto de Estudios de Red. Red Eléctrica de España SA. Spain

The rapid growth of wind power, which has reached 13,908 MW at the end of 2007, along with the installation of other technologies like solar power, mini-hydraulic or cogeneration plants have lead to the consideration of special regime generation as another major fraction of the Spanish electrical generation mix. In order to supervise, control and integrate the Spanish TSO (Red Eléctrica de España) has launched in June 2006 the Control Centre for Renewable Energies (CECRE) which deals with the specific challenges of these technologies with the goal of maximizing their production without jeopardizing the security of the electric system.

302 two sheets summary

303 Model of integrated pool/conventional/alternative electricity market operation using pay-as-bid pricing
Fabio Stacke(1), Pablo Cuervo(2)
(1). Brazilian Electricity Regulatory Agency- ANEEL. Brasil
(2). University of Brasília. Brasil

A model with interaction of pool, conventional and alternative markets in a power system inserts a competition for alternative power plants separating the pricing with 'Pay-as-Bid' (PAB) approach in opposite of classical Marginal Pricing (MP) because the inelastic demand characteristic and the necessity of reduce total operation cost. Agents can plan portfolios based on reasonable stable prices that reflect impact of supplying several electricity types and associated costs of resources in several operation scenarios and bid strategies. The minimization of payments by PAB ensures the supply of energy, transmission losses and alternative energy requirements as well as enforcing financial adequacy.

305 Optimal pumping in a single chamber microbial fuel cell
A. Araújo, Maria F. Patrício, José L. Santos
CMUC, Department of Mathematics, University of Coimbra. Portugal

In this work we study the numerical behaviour of a diffusion equation with a discrete source term and control variables. Our goal is to use optimization techniques in order to obtain a numerical solution that minimizes a given objective function taking into account some restrictions. Some numerical results are presented concerning the application into a model that describes the oxygen concentration in a single chamber microbial fuel cell. These numerical results are used to obtain a continuous approximation with the least-squares method.

308 Influence of capacitances on the impedance-based methods for SLG fault location in distribution networks
S. Herraiz(1), J. Meléndez(1), J. Sánchez(2)
(1). Institute of Computer Science and Applications, University of Girona. Spain

309 Biomass for power and energy generation
Narsimhulu Sanke(1), D.N. Reddy(2)
(1). Dept. of Mechanical Engineering, University College of Engineering, Osmania University. India
(2). Center for Energy Technology, University of Engineering, Osmania University. India

Biomass is a scientific term for living matter, more specifically any organic matter that has been derived from plants as a result of the photosynthetic conversion process. The word biomass is also used to denote the products derived from living organisms - wood from trees, harvested grasses, plant parts, and residues such as stems and leaves, as well as aquatic plants. The solid biomass processing facility may also generate process heat and electric power. As more efficient bioenergy technologies are developed, fossil fuel inputs will be reduced; biomass and its by-products can also be used as sources for fuelling many energy needs. The energy value of biomass from plant matter originally comes from solar energy through the process known as photosynthesis. In nature, all biomass ultimately decomposes to its elementary molecules with the release of heat. During conversion processes such as combustion, biomass releases its energy, often in the form of heat, and the carbon is re-oxidized to carbon dioxide to replace that which was absorbed while the plant was growing. Essentially the use of biomass for energy is the reversal of photosynthesis.

311 Application of genetic algorithms to compute the magnetic field produced by electric power lines
F. Muñoz, J.A. Aguado, F. Martín, J.J. López, A. Rodríguez, J.E. Ruiz
Department of Electrical Engineering. E.T.S.I.I.-E.U.P. Málaga. Spain

315 On the dependence between the step orientation and the received direct solar radiance of a PV panel. Part I: the step azimuthal orientation
Ion Visa, Dorin Diaconescu, Valentina Popa
Product Design Centre for Sustainable Development, Transilvania University of Brasov. Romania

The approached problem regards the energetic efficiency maximization of a tracked PV panel by maximizing the received direct solar radiation, with minimum driving energy.

The objective of this first paper part is to optimize correlation between the panel received direct solar radiation and the daytime tracking steps' number, in case of an azimuthal tracked PV panel. The paper presents a graphical solving of the problem; from these solutions, an optimization analytic model will be developed in the future.

315 two sheets summary

316 On the dependence between the step orientation and the received direct solar radiance of a PV panel. Part II: the pseudo-equatorial orientation
Dorin Diaconescu, Ion Visa, Bogdan Burduhos, Radu Saulescu
Product Design Centre for Sustainable Development,Transilvania University of Brasov. Romania

This second part of the paper approaches a problem that is referring to the energetic efficiency maximization of a tracked PV panel, which consists in maximizing the received solar radiation and minimizing the driving energy. The objective is to optimize the "received direct solar radiation" - "number of daytime tracking steps" correlation for a pseudo-equatorially tracked PV panel (Fig. 1). The solution presented is a graphical one and an analytic model will be developed in the future.

316 two sheets summary

317 Wind energy systems and power quality: matrix versus two-level converters
R. Melício(1), V.M.F. Mendes(1), J.P.S. Catalão(2)
(1). Instituto Superior de Engenharia. Lisbon. Portugal
(2). Univesity of Beira Interior, Covilhã, Portugal

This paper presents data of the actual installed electric power capacity for the renewable energy power systems in Portugal. Also, this paper presents a contribution consisting in a modulation strategy for simulation of a wind energy system with different topologies for power converters, consisting on a matrix and a two-level converter. Although more complex, this modulation strategy is justified for more accurate results.

317 two sheets summary

322 Super-capacitor integration into hybrid vehicle power source
V. Bršlica
Department of Electrical Engineering. University of Defence in Brno. Czech Republic

The hybrid vehicle based on the concept of battery operated electrical vehicle, where small ICE provides primarily the thermal comfort in cabin, gains practically all the traction power from the battery, and in economic mode the coupled generator delivers only low power for battery recharging. The power peaks, which are necessary for good dynamics and recuperation, damage the battery electrodes and shorten its lifetime. The super-capacitor, with much better charging efficiency, can store the energy from braking to the next acceleration. Its sizing and voltage control is discussed in this paper.

324 Power factor improvement of DC/DC converter of micro-turbines
H.R. Baghaee(1), M. Mirsalim(2) , .M.Ale-Emran(1), M. Abedi(1), G.B. Gharehpetian(1)
(1). Electrical Engineering Department Amirkabir University of Technology . Tehran. Iran
(2). Electrical Engineering Department at St. Mary´s University, San Antonio, TX,US

The distributed generation interconnection to the power system can have impact not only on the power flow, but also on power quality of customers, and utilities. This paper proposes a multi-function nonlinear link for distribution generation systems. The main function of this link is to regulate the active power supplied from distribution generation to the utility. The link can also supply reactive power to the utility to enable unity power factor operation or to regulate the voltage at the point of common coupling. This link can also be controlled to mitigate power quality problems. Genetic algorithm is also used for the optimization of parameters of the power factor correction controller. The simulation performed in MATLAB/Simulink validates the effectiveness of the proposed power factor scheme.

326 Mathematical Modeling and Simulation of Photovoltaic Array
Tomas Skocil(1), M.P. Donsión(2)
(1). Department of Electrical Power Engineering and Ecology, Faculty of Electrical Engineering in Pilzen, University of West Bohemia, Czech Republic.
(2).Department of Electrical Engineering, Vigo University, Spain.

326 two sheets summary

327 An overview on short and long-term response energy storage devices for power systems applications
Sérgio Faias(1), Patrícia Santos(1), Jorge Sousa(1), Rui Castro(2)
(1). Instituto Superior de Engenharia de Lisboa, DEEA/ISEL. Portugal
(2). Instituto Superior Técnico/Technical University of Lisbom. IST/TUL. Portugal

Energy storage devices provide valuable benefits to improve stability, power quality and reliability of supply. Storage technologies have developed significantly in order to meet the challenges of practical power systems applications.

Energy storage devices can be classified into short and long-term response, depending on their application. Technologies with high power density and with the ability to respond to the requests in short time fractions like flywheels, capacitors or superconducting magnetic coils belong to the so-called short-term response energy storage devices category. Energy storage devices with the capability to absorb and supply electrical energy for long periods of time like pumping hydro, batteries, compressed air and hydrogen fuel cells are considered in the long-term response category.

This paper focuses on the latest short and long-term energy storage technology developments, performance analysis, and cost considerations.

327 two sheets summary

332 A case study of risk analysis due to lightning for wind power plants
R.B. Rodrigues(1), V.M.F. Mendes(1), J.P.S. Catalão(2)
(1). Instituto Superior de Engenharia. Lisbon. Portugal
(2). University of Beira Interior, Covilhã, Portugal

This paper briefly describes the Portuguese Lightning Location System, and presents an overview of wind energy in Portugal. The method for risk assessment due to lightning flashes to earth, proposed by the International Electrotechnical Commission, IEC, is used. A wind power plant is characterized for a case study, and the standard IEC 62305-2 is applied. Results obtained are able to support the advantage for investors to take into account the lighting activity in the region where the wind power plant shall be installed. Also, the use of a well established risk assessment method allows the adoption of adequate protection measures.

332 two sheets summary

333 Moving actuator surfaces: a new concept for wind turbine aerodynamic analysis
Christian Masson, Christophe Sibuet Watters
Department of Mechanical Engineering. École de Technologie Supérieure. Canada

The actuator disk is a concept often used in wind turbine aerodynamics, where the action of the turbine on the flow is averaged over time and space. This simplification stills retain sufficient physical information for wind turbine aerodynamic design. Its limitations are essentially related to the impossibility to model the blade shed vorticity. This paper presents a more general approach that uses rotating actuator surfaces carrying velocity and pressure discontinuities which are set from knowledge of the circulation around the model blade sections and using blade element analysis. The mathematics of rotating actuator surfaces, as well as an application to the TUDelft rotor are presented in this paper. The results are encouraging.

335 Real time power disturbance characterization system based on wavelet transform and LabView platform
J.E. Ruiz, J. Aguado, F. Martín, F. Muñoz, J.J. López, A. Rodríguez
Department of Electrical Engineering. E.T.S.I.I. Málaga University. Spain

336 Dynamic performance of a microturbine connected to a low voltage network
E.Torres(1), J.M. Larragueta(1), P. Eguia(1), J. Mazón(1), J.I. San Martín(2), I. Zamora(1)
(1). Department of Electrical Engineering .E.T.S.I.- Bilbao. Spain
(2). Department of Electrical Engineering. E.U.I.T.I.- Eibar. Spain

Nowadays there is a great interest for the use of microturbines as sources of distributed generation, particularly in areas where demand is both electricity and heat. In these areas microturbines reach very high efficiency rates. Microturbines can operate both stand-alone and grid connected. The second one of the mentioned possibilities is which deserves a much deeper study, to analyse the interaction of the microturbine with the distribution network it is connected to.
In this paper a dynamic model of a microturbine is developed with Matlab/Simulink/Simpowersystems. The model has been included within a low voltage network model and several dynamic simulations have been performed to study the response to step changes in the power control references. Also, the performance of the microturbine to faults in the network has been analysed.

336 two sheets summary

337 Solar intensity estimation in a geographical region based on agents
J.A. Ramos Hernanz(1),J.J. Campayo Martín(1), I. Zamora Belver(2), E. Puelles Pérez(1), E. Zulueta Guerrero(3)
(1). Department of Electrical Engineering E.U.I. Vitoria- Gasteiz. University of The Basque Country. Spain
(2). Department of Electrical Engineering. E.T.S.I. Bilbao. University of The Basque Country. Spain
(3). Department of Systems Engineering and Automatic. E.U.I.Vitoria-Gasteiz. University of The Basque Country. Spain

337 two sheets summary

338 A new design approach for ground source heat pumps based on hourly load simulations
L. Lamarche, G. Dupré, S. Kajl
Department of Mechanical Engineering. École de Technologie Supérieure. Canada

339 Comparison of transmission and distribution systems in Czech Republic and Spain
F. Rajsky(1), M.P. Donsión(2)
(1). Department of Electrical Power Engineering and Ecology, Faculty of Electrical Engineering in Pilzen, University of West Bohemia, Czech Republic.
(2). Department of Electrical Engineering, Vigo University, Spain.

339 two sheets summary

340 Design of control strategies to improve grid integration in fixed speed wind energy systems with battery storage
A. Goikoetxea(1), M. Rodríguez(1), H. Binder(2), A. Milo(3)
(1). Faculty of Engineering. University of Mondragon. Spain
(2). Riso National Laboratory, Technical University of Denmark
(3). Department of Control Engineering, IKERLAN, Research Centre. Mondragon. Spain

341 Performance of rotational speed controlled small-scale head-dependent hydroelectric power plant
Tuomo Lindh, Risto Tiainen, Jero Ahola, Markku Niemelä, Ville Särkimäki
Lappeenranta University of Technology. Finland

Frequency converters can be utilized in a small or micro scale hydropower plant as a control method alternative to using a adjustable blade angle turbine or a bank of fixed blade angle turbines which can form different combinations to keep the head variation as low as possible (two-point control). The overall economical feasibility of the options will be determined by their investment and operating (maintenance) costs, and the efficiency. However, the operational costs are not discussed in this paper. The feasibility of the rotational speed control method is studied and compared to two point control and to mechanical blade angle control by estimating investment costs and profit differences due to differences in efficiency and in control method. Also, general remarks on the factors that influence the feasibility of rotational speed control are given. An example feasibility calculation of a pilot plant is given in the case where one of the four parallel submerged fixed blade turbogenerators is equipped with a frequency converter.

342 Rewiew of methods for a hybrid energy system islanding efficient management
Á. Llaría(1), O. Curea(1), J. Jiménez(2), U. Bidarte(2)
(1). LIPSI. École Supérieure des Technologies Industrielles Avancées. France
(2). Departamento de Electrónica y Telecomunicaciones. University of The Basque Country. Spain

Nowadays, when a long time problem happens in the electric net, Hybrid Energy Systems (HES) can be disconnected of it to avoid damages. The aim of the research described in this paper is to study the possibility that the HES, once it has been disconnected, could be able to provide energy to near loads creating a micro-grid (islanding scenario).
When in islanding, it is important to connect or disconnect the loads depending on the available energy. The control of that feature will be performed by means of Demand Side Management (DSM), using wireless communications and analyzing different options.

344 Piezoelectric generator harvesting bike vibrations energy to supply portable devices
Ericka Minazara(1), Dejan Vasic(1,2), François Costa(1,3)
(1). SATIE. Université de Cergy-Pontoise. France
(2). Université de Cergy-Pontoise. France
(3). IUFM. France

With the decrease in energy consumption of portable electronic devices, the concept of harvesting renewable energy in human surrounding arouses a renewed interest. In this context, we have developed a piezoelectric generator that harvests mechanical vibrations energy available on a bicycle. Embarked piezoelectric transducer, which is an electromechanical converter, undergoes mechanical vibrations therefore produce electricity. A static converter transforms the electrical energy in a suitable form to supply LED lamp installed at the front head of the bike. Values of generated electrical power are reported and commented.

345 Energy price-based control strategy of a small-scale head-dependent hydroelectric power plant
Risto Tiainen, Tuomo Lindh, Jero Ahola, Markku Niemelä, Ville Särkimäki
Lappeenranta University of Technology. Finland

347 Power line carrier communications and its interest in the current power grid scenario
O. Abarrategui, I. Zamora, DM. Larruskain, A. Iturregi
Department of Electrical Engineering. UPV - EHU. Spain

347 two sheets summary

350 Wind energy integration into 380 kV system-impact on power quality of MV and LV networks
Elda Vilchez, Jürgen. Stenzel
Technische Universität Darmstadt. Germany

352 How the efficiency of induction motor is measured?
S. Corino, E. Romero,LF. Mantilla
Department of Electrical Engineering and Energy. E.T.S.I.I. y T. University of Cantabria. Spain

352 two sheets summary

354 Control of series active power filter by state feedback
S.P. Litrán, P. Salmerón, R.S. Herrera, J.R. Vázquez
Electrical Engineering Department. Huelva University. Spain

The active power filters in series connection (APFs), are static compensation systems based on an electronic converter PWM. The connection of series APFs in the power systems allows elimination of the harmonics caused by specific loads. To obtain the compensation objective, several strategies have been proposed up now. Nevertheless, each strategy developed has been based on the equivalent electrical circuit and/or simulation tests. In this work, the whole system state model has been obtained. Besides, the system behavior has been analyzed from the state equations for each compensation strategy. This analysis has allowed establishing design rules respect to the resultant control strategy. Finally, a practical case is presented.

354 two sheets summary

362 Diagnostic information contained in inter-harmonics of a direct and PWM supplied induction machine
Jan Rusek
AGH University of Science and Technology. Krakow. Poland

The paper contains waveforms of currents for direct and PWM supplied induction machine, with account for harmonics and inter-harmonics. Calculations of currents are based on dynamical model. By direct supply the grid is assumed to be polluted by 3rd, 5th and 7th harmonics. The PWM voltage inverter was assumed to operate with perfectly constant DC link current. Spectrums of stator currents are examined to distinguish harmonics bearing information on static, dynamic and mixed eccentricities. The model of the machine accounts for dependencies of stator and rotor inductances on rotor angle, resulting from winding and air gap geometry.

362 two sheets summary

364 A dynamic model of a vertical direct expansion ground heat exchanger
B. Beauchamp, L. Lamarche, S. Kajl
Department of Mechanical Engineering. École de Technologie Supérieure. Montreal. Canada

The paper presents a general distributed model of a vertical U-tube direct expansion heat exchanger coupled with the ground. This model is developed for studying the dynamic thermal behavior of a buried heat exchanger (the evaporator or condenser) which is an integral part of the so-called direct expansion heat pump. The transient conservative equations of mass and energy considering the two-phase flow of refrigerant are derived and presented. The heat exchange with the ground and the thermal interference between the two pipes of the heat exchanger are considered. Experimental data from a test rig are used to demonstrate the validity of the dynamic model.

365 Generalized fourier series - a useful mathematical tool in power electronics
A.Jan Iwaszkiewicz(1), B. Jacek Perz(1), M. Pérez Donsión(2)
(1). The Electrotechnical Institute, Gdansk Branch. Poland
(2). Electrical Engineering Department. Vigo University. Spain

366 Influence of converter - connected distributed generation on distribution network losses
Lieven Degroote, Bert Renders, Bart Meersman, Lieven Vandevelde
Electrical Energy Laboratory ( EELAB).Department of Electrical Energy, Systems and Automation (EESA) Ghent University. Belgium

368 Fuel cell inverters used for unbalance compensation in low voltage distribution systems
Héctor Beltrán, Néstor Aparicio, E. Belenguer, C. Cervelló García
Department of Industrial Engineering Systems and Design. Universitat Jaume I. Castelló de la Plana. Spain

368 two sheets summary

370 Electrical charge and discharge characteristics of battery under remote control of water level with PV pumping system
Masaki Sato, Yuhta Ohmi, Shingo Kato
Hachinohe Institute of Technology Graduate School. Japan

370 two sheets summary

373 Control method for the improvement of the efficiency of a fuell cell
Radu C. Donca, Radu Balan, Vistrian Maties, Olimpiu Hancu
Department of Mechanisms, Precision Mechanics and Mechatronics. Faculty of Mechanics, Technical University of Cluj- Napoca. Romania

374 A multivariable model for identification of preferred location of wind plants
Ali Azadeh, Seyed Farid Ghaderi, Mohammad Reza Nasrollahi
Faculty of Engineering, University of Theran. Iran

Environmentally friendly benefits of wind power plants make them very desirable. Hence determination the optimum locations for use of this resource is a vital decision. Generally, there are several parameters models that are used to specify the locations of wind plants. But, because of problems with these models, there are great amount of uncertainly in using them and many of them are local models that only can be used for specific places. In this article we proposed a Multivariable Model (DEA) approach that uses a number of predefined parameters that can be used to identity optimum locations of wind power plants in a country, region, etc. DEA is used to rank various locations capabilities with respect to four outputs and one input. Furthermore existing data is also used to verify and validate the DEA results. The integrated approach has been applied to twenty five different locations in Iran and may be easily used for other countries or regions. This would result in significant saving when compared with conventional methods of measurements for location optimization.

376 Optimization of a photovoltaic installation supported with hydrogen. Study of the influence of the tilt angle of the modules
M. Calderón(1), A. Ramiro(2), J.F. González(2)
(1). Department of Electrical Engineering . E.I.I. Extremadura University. Badajoz. Spain
(2). Department of Applied Physics. E.I.I. Extremadura University. Badajoz. Spain

The aim of this work is to analyze the influence of the tilt angle of the photovoltaic modules on the efficiency of a autonomous photovoltaic installation isolated from power supply and supported with hydrogen by a Fuel Cell. The photovoltaic modules were oriented to face south in all the cases.

378 Capacity planning for fossil fuel and renewable energy resources power plants
Farid Ghaderi(1), Reza Tanha(1), Ahmad Karimi(2)
(1). Department of Industrial Engineering, Tehran University. Iran.
(2). Department of Mathematics, Tarbiat Modares University. Tehran. Iran

Electricity industry is changing by organizational and legislative evolutions dealing with economical and environmental affairs. Besides rapid development in energy generation decreased the related variable costs, considering environmental issues. In this study energy generation technologies are evaluated both from economical and environmental views. Applying Analytical Hierarchy Process (AHP) which is extremely applicable and known as one of the efficient methods to analyze complicated multi criteria problems it is achieved interesting results from evaluation. The main goal of this evaluation which is presented in this essay is to extract total preference weights for generation technology. Total preference weights are determined considering four criteria in fossil fuel power plants and renewable energy resources power plant using this evaluation pattern. For three power plant of gas, steam and combine cycle the total preference weights are calculated by considering seven criteria. For the next eight power plants of wind, small hydro, photovoltaic, solar thermal, micro turbine, biomass, geothermal and fuel cell total preference weights is considered according to seven criteria. Optimum capacity is calculated and determined. Sensitivity analysis is made on two most important criteria of this model named 1- operation and investment cost, and 2-fossil resources scarcity for power plants. 1- Multiple criteria of objective function, 2-possibility of sensitivity analysis on criteria weights and 3-concurrent inspection of qualitative and quantitative criteria in optimization of objective function are three advantages of the proposed model comparing common applying method such as (mono- objective software WASP)

379 Optimizing consumption and emission in gas fuel consuming power applyinf DEA model
Samaneh Shokravi, Farid Ghaderi
Department of Industrial Engineering. Faculty of Engineering, University of Theran. Iran

In this paper, energy consumption and carbon dioxide emission of the Iran gas generators is studied using Data Envelopment Analysis (DEA), which is a methodology based upon an interesting application of linear programming, and Goal Programming (GP) to show the importance of CO2 emission in Iran like most other countries and also conserve fuel as key role of today life and industry. Ramanathan studied energy consumption and carbon dioxide emission as well, from 17 countries of the Middle East and North Africa (MENA) with four indicators for the year 1996. In this paper a simple goal programming model to minimizing carbon dioxide emission and gas consumption is revealed for the year of 2004 by employing three main indicators. First electricity generated by generators, then carbon dioxide emission and at last natural gas consumption as generators consuming fuel. Model is attempted to minimize the cost and shows that a new management approach is vital and with replacing the clean fuel the demolition cost decrease. The analysis concludes the most and least efficient units and revealed an optimizing model which its results are comparable to international standards for CO2 emission and fuel consumption, although there are some other indicators to refer to for this kind of studies, such as environmental and technical factors, age of machineries, primary investment, repair and maintenance expenses, and efficiency of process and etc, that could be considered for future papers and required to develop the model to compass the new and acceptable factors.

380 Wave power conversion systems for electrical energy production
A. Leão Rodrigues
Department of Electrical Engineering. Faculty of Science and Technology Nova University of Lisbon. Portugal

After a brief description of wave formation and quantifying the power per length of wave front associated to the wave, the paper describes several wave devices located at shoreline, nearshore and offshore, such as oscillating column of water, underwater pneumatic systems, wave dragon system and oscillating bodies systems. These mechanisms can be lying on seabed and on the sea level. A description of the Pelamis Wave System is also made. It is a revolutionary concept resulting from many years of engineering development, being the world's first commercial scale machine to generate electrical energy into the grid from offshore wave energy.

380 two sheets summary

381 Olive stone: a source of energy generation and a suitable precursor for activated carbon production
S. Román(1), J.F. González(1), J.M. Encinar(2)
(1). Department of Applied Physics. Extremadura University. Badajoz. Spain
(2). Department of Chemical Engineering and Physical Chemistry. Extremadura Univesity. Badajoz. Spain

Among all the technologies proposed to provide sustainable energy, biomass thermochemical processes are one of the most important because of biomass availability, clean character and possibility of using biomass wastes (which involve a disposal problem). Moreover, focussing on biomass pyrolysis, it generates a solid carbonaceous residue which could be used as precursor for activated carbon production. This work is focussed on the study of the reactions involved in the process of steam and CO2 gasification of olive stone char, in order to optimize both the energy content in the gas generated and the development of porosity produced.

383 Storage systems for the transition towards active and smart distribution systems
S. Barsali(1), A. di Donato(1), R. Giglioli(1), L. Guidi(2), E. Pasça(2), S. Scalari(2)
(1). Università di Pisa. Dipartimento di Sistemi Elettrici e Automazione. Pisa. Italy
(2). ENEL. Pisa. Italy
The paper presents the criteria adopted for designing a storage system to be used in a distribution grid where several distributed resources exist. The purpose of introducing storage in distribution is to enable the operators to manage the grid as a really active system. A droop based control system has been designed and tested through simulations which are presented in the paper. The results are currently being used to specify and build a prototype device to be installed in a test facility where Enel will develop a "smart grid".

385 Energy policy of the European Union: Impact of the renewable energies and perspectives for the year 2020
C. Redondo Gil(1), L.A. Esquibel(1), A.M. Alonso Sánchez(1), F.J. Velasco(2)
(1). Department of Electrical Engineering & Systems Engineering and Automatic Control. University of Leon. Spain
(2). Department of Electronic Technology. University of Cantabria. Spain

385 two sheets summary

392 Optimal operation of paralleled power transformers
David Trebolle(1), Baudilio Valecillos(2)
(2). University Carlos III of Madrid. Spain

In the parallel operation of power transformers interest is placed on minimizing the reactive current circulation due to mismatching of electrical properties. Classical methods either rely on measurements of circulating currents, or Master/Follower approach to ensure efficient operation of paralleled transformers with OLTC. On the present work a map of circulating current is calculated based on the transformers impedances, and OLTC positions, then the optimal tap positions (minimizing losses) are determined. The distribution system SCADA is used to control tap position of the paralleled transformers. Also a complete regional risk map provides a list of transformers feasible for paralleled operation.

393 Optimal relay performance using advanced fault diagnostic techniques
Akinbulire,T.O., Oluseyi, P.O.,Esumeh, C.I.
Department of Electrical/ Electronics Engineering. University of Lagos. Nigeria

393 two sheets summary

394 The application of active filters supported by Pulse Width Modulated Inverters in the harmonic simulation of the high power electric traction
Peter Kiss(1), Attila Balogh(2), András Dán(1), István Varjasi(2)
(1). Budapest University of Technology and Economics. Department of Electric Power Engineering Power Systems and Environment Group. Hungary
(2). Budapest University of Technology and Economics. Department of Automation and Applied Informatics . Hungary

The paper shows the present results of a long term research work. The authors are working on the modelling of active filtering of harmonics caused by the railways.

To simulate the harmonic penetration and filtering effects of the power electric traction the combination of frequency and time dependent model should be used. This novel method, called double domain simulation is improving the accuracy of the frequency domain simulation. To calculate the sophisticated model of the electric locomotive and active harmonic filter as a non-linear load a time dependent model must be used. The traction supply system together with the equivalent supply network impedance could be calculated in frequency domain. An iteration algorithm is developed converting the variables in every iteration step between the time and frequency domain.
394 two sheets summary

395 Integrating power quality analysis and protection relay functions
Aleksander Lisowiec, Andrzej Nowakowski, Zdzislaw Kolodziejczyk
Tele & Radio Research Institute. Warsaw. Poland

In the paper the implementation of power quality analysis functions in protection relay has been presented. The main focus of the research has been on the development of efficient algorithms for voltage and current signals frequency spectrum determination with harmonic and interharmonic content up to 2 kHz. The technique that enables efficient implementation of frequency spectrum determination in protection relay employed in systems with varying line frequency is resampling in the digital domain. The accuracy analysis of the resampling technique applied in a protection relay, taking into account implementation issues, has been carried out.

395 two sheets summary

397 Possibility of application of a low frequency inductive heating to selected ferromagnetic objects
B. Miedzinski(1), Z. Okraszewski(1), Liang-jun Xu(2), Xin Wang(2)
(1). Wroclaw Univesity of Technology. Poland
(2). Beijing University of Posts and Telecommunications. China

398 Speed multipliers for renewable energy systems-hydro and wind
Codruta Jaliu, Dorin Diaconescu, Radu Saulescu
Department of Product Design and Robotics. Transilvania University of Brasov. Romania

400 Statiscal processing of data coming from a photovoltaic plant for accurate energy planning
Annalisa Di Piazza, Maria Carmela Di Piazza, Gianpaolo Vitale
Instituto di Studi sui Sistemi Intelligenti per L´Automazione (ISSIA-CNR). Palermo. Italy

This paper presents a statistical approach to manage sampled data coming from a photovoltaic installation by performing measurements from June to October and sampling each 10 minutes. The proposed statistical methods are the k-means clustering and the normal density probability distribution. The use of the proposed methods allows to simplify the problem of the PV plant energy assessment respect to the option of obtaining the desired information by managing a large amount of experimental observations. The deviation between estimated and actual produced energy is equal to 1.2% with k-means clustering and to 1.8% with normal density probability distribution.

400 two sheets summary

401 Comparison of control techniques for three-phase distributed generation based on VOC and DPC
Graziella Giglia, Marcello Pucci, Calogero Serporta, Gianpaolo Vitale
ISSIA-CNR. Palermo. Italy

This paper presents a comparison among control strategies of active rectifiers used for grid connected distributed generation systems from renewable sources.
The considered techniques are: Voltage Oriented Control (VOC), Direct Power Control (DPC), two DPC based techniques to minimize the Common Mode (CM) emissions called DPC-EMC1 and DPC-EMC2 set up by the authors and their versions based on virtual flux.
All the described techniques have been implemented using Matlab-Simulink environment and PLECS.
In the results the current injected into the grid, the THD of the injected current vs generated power and vs DC link voltage and the CM voltage are shown.

401 two sheets summary

402 Photovoltaic panels labViewTM controlled- a platform for educational purposes
Nuno Faria(1), António Bonifácio(1), João Pedro Trovão(1.2)., Paulo Tavares(1.2)
(1). Instituto Superior de Engenharia de Coimbra. Portugal
(2). Instituto de Engenharia de Sistemas e Computadores de Coimbra. Portugal

This paper presents a platform for educational purposes, based on photovoltaic panels LabViewTM controlled. The objective of this work is to give a contribution to the sustainable development. For this, a batteries charging with PV panels study, in respect to several measurement and how this variables change according to Sun position and PV panels orientation, is presented. A database with these variables is created. Another particularity is the control of two electric motors in order to move the PV panels through the day to achieve the optimal set-up. Finally, a cost study of three possible configurations versus generated power, project conclusions, possible applications and future studies based on this work are presented.

402 two sheets summary

404 Unified power quality conditioner with electric double layer capacitor
B. Han, H. Lee, J. Lee
Department of Electrical Engineering, Myongji University, Kyunggi-do, South Korea

This paper proposes a new configuration of UPQC (Unified Power Quality Conditioner) that consists of the DC/DC converter and the electric double layer capacitors for compensating the voltage interruption. The proposed UPQC can compensate the reactive power, harmonic current, voltage sag and swell, voltage unbalance, and the voltage interruption. The performance of proposed system was verified through experimental works with a prototype. The proposed system can improve the power quality at the common connection point of the non-linear load and the sensitive load.

407 First results of the anomalies identification method for PV systems
A.López Agüera(1), I. Rodriguez Cabo(1), Eduardo Fernández(1), C.M. Torres Costa(2)
(1). Department of Particle Physics & Galician Institute of High Energy Physics. Santiago de Compostela University. Spain.
(2). Department Chemical Engineering. Aula Enerxias Renovables. Santiago de Compostela University. Spain

407 two sheets summary

408 Architectural integration of renewable energies in historical cities
A. López Agüera, I. Rodriguez Cabo, I. Fernández, V. Gándara
Department of Particle Physics & Galician Institute of High Energy Physics. Santiago de Compostela University. Spain.

409 Permanent Magnet Synchronous Motors (PMSM). Parameters influence on the synchronization Process of a PMSM
J. Rais(1), M.P. Donsión(2)
1.- Department of Electromechanics and Power Electronics, Faculty of Electrical Engineering in Pilzen, University of West Bohemia, Czech Republic.
2.- Department of Electrical Engineering, Vigo University, Spain.

409 two sheets summary

412 Finite element analysis of cogging torque in low speed permanent magnets wind generators
T. Tudorache(1), L. Melcescu(1), M. Popescu(2), M. Cistelecan(2)
(1). University Politehnica of Bucharest, Electrical Engineering Faculty. Romania
(2). Research Institute for Electrical Machines (ICPE-ME). Romania

412 two sheets summary

415 Pyrolysis and catalytic steam gasification of olive oil waste in two stages
J. M. Encinar(1), J.F. González(2), G. Martínez(1), M.J. Martín(1)
(1). Dpto Ingeniería Química y Química Física. UEX. Badajoz. Spain
(2). Dpto Física Aplicada. UEX. Badajoz. Spain

417 Classification of voltage sags base on k-NN in the principal component space
J. Meléndez(1) X. Berjaga(1), S. Herraiz(1), J. Sánchez(2), M. Castro(2)
(1). Institut d´Informàtica I Aplicacions Universitat de Girona.Spain
(2). Power Quality Department of Endesa Distribución, Barcelona. Spain

417 two sheets summary

423 Improving the environmental sustainability of hotel buildings through the analysis of its life cycle. Case study: Balearic Islands
B. Roselló, A. Moia, A. Cladera, V. Martínez
Department of Physics-Mechanical Engineering Group. University of Balearic Islands. Spain

425 Study and comparison of technologies in home and building electronic systems by fuzzy logic
R. Sáenz López(1), E. Jiménez Macías(1), M. Pérez de la Parte(2)
(1). Department of Electrical Engineering. E.T.S..I.I. University of La Rioja. Spain
(2).Department of Mechanical Engineering. E.T.S.I.I.University of La Rioja. Spain

There exist many systems of automation, energy management and security for housings and buildings, and multiple factors that determine the most appropriate one. This work considers the most outstanding factors for the selection as input variables of a fuzzy model, where the output variables measure the grade of adaptation of every system. A high number of rules are defined to develop the inference and generate the output values. The proposed model is developed with the Fuzzy Logic Toolbox of MATLAB, and is evaluated on ten different cases, which are presented to show the behaviour of the model and the results.

425 two sheets summary

426 Micro-hydraulic energy system for electric power production and DSM in buildings
J.C. Sáenz-Díez Muro(1), J.M. Blanco Barrero(1), E. Jiménez Macías(1), M. Pérez de la Parte(2)
(1). Department of Electrical Engineering. E.T.S..I.I. University of La Rioja. Spain
(2). Department of Mechanical Engineering. E.T.S.I.I.University of La Rioja. Spain

In this article a procedure of electric power obtaining is presented, based on the micro-hydraulic application derived from the supply pressure of water in the cities; this constitute a step more toward the objective of sustainable buildings (energy and environmentally speaking), and is integrated into the generat electrical power management in biuldings with the main renewable energy systems for electrical supply (basicaly wind and solar energy). The proposed system can be more important in non-developed countries, where the electric supply is not totally reliable, and the water supply of the buildings is made by using water tanks on the top.

426 two sheets summary

427 Modelization of earth electrode excited by atmospheric discharges based on FEM
J.M. Bueno Barrachina, C.S. Cañas Peñuelas, S. Catalán Izquierdo, A. Quijano López
Instituto de Tecnologia Eléctrica. Valencia. Spain

The aim of this paper is to obtain the distribution of tensions in the land excited by currents type ray using different types of electrodes: the goad electrodes and the deep goad electrodes, and as an exceptional case an electrode type drags was used.
In this work, the program ANSYS® that is based on the finite elements method (FEM) was used. After the simulation of the distribution of tensions, different parameters were obtained, such as the tensions of step (Vp) and of contact (Vc) which determine the security of the installation of put in the earth (PE) protection.

427 two sheets summary

430 Development of micro grid model for stability assessment
I.Vokony, A. Faludi, A. Dán
Faculty of Electrical Engineering, Budapest University of Technology and Economics. Hungary

430 two sheets summary

431 Performance limitations of B6 inverters during unsymmetrical voltage sag conditions
A. Notholt(1), D. Coll- Mayor(2)
(1). Institut für solare Energieversorgungstechnik. Germany
(2). University of Balearic Islands, Physics Department. Spain

432 Circunstances affecting the protection against electrode potential rise (EPR)
József Ladányi, György Varjú
Budapest University of Technology and Economics, Department of Electric Power Engineering. Hungary

Required power of the big cities keeps growing year by year. It is necessary to establish new high voltage (HV) / medium voltage (MV) transformer stations to satisfy power demand in densely populated urban areas. The area available for installing HV/MV substation is restricted and becomes more and more expensive in the city.
In this paper the earthing resistance of substations with different earth electrode and soil structures is investigated by simulation studies with the use of CDEGS (Current Distribution, Electromagnetic Fields, Grounding and Soil Structure Analysis) software code. The paper presents the effect of grid geometry, soil characteristics, the effectiveness of the vertical earth rods and the conductor diameter.

432 two sheets summary

434 Ultra low quiescent consumption isolated PFM power supplies under no-load condition
José Miguel de Diego Rodrigo(1), José Ignácio Garate Añibarro(1), Javier Monsalve Kägi(2)
(1).UPV, Escuela Técnica Superior de Ingeniería. Bilbao. Spain
(2). Maxim Integrated Products, Inc.

437 Two-dimensional analytical modelling of passive-feed direct methanol fuel cells
Piergiorgio Alotto, Massimo Guarnieri, Federico Moro
Dipartimento di Ingegneria Elettrica, Università di Padova. Italy

Direct methanol fuel cells are regarded nowadays as promising energy sources for portable electronic devices. Numerical models can be very useful for addressing the exploration of the fuel cell performance, without the development of many prototypes, which can be very expensive due to the presence of rear materials. Analytical models are particularly suited for investigating the cell performance with limited computing costs.

In this work, a two-dimensional model for assessing the performance of an active-feed direct methanol fuel cell is presented, accounting for electrochemical reactions, mass and heat transfer.

437 two sheets summary

439 A switched reluctance generator behavior under variable speed and variable excitation
Ribeiro, F.S.L., Cabral L.G., Fleury, A.
Laboratório de Máquinas Elétricas da Universidade Católica de Goiás. Brasil

The subject of this paper is the wind powered Switched Reluctance Generator - SRG and its behavior. Simulations and experimental results are presented. It was analyzed the efficiency of SRG under different conditions. Many operational test were conduced to state clearly the behavior of a prototype drove by a half-bridge (HB) converter. Variable excitation voltage and angular speed relationship are established clearly. It shows that the suitable excitation control for a wind powered SRG must adjust the operation parameters to match the desired point on certain surfaces.

441 A constructal approach to power distribution networks design
Alexandru M. Morega(1), Juan C. Ordonez(2), Mihaela Morega(1)
(1). Politehnica University of Bucharest, Romania
(2).Department of Mechanical Engineering, Florida State University . USA

Superior, scalable grid topology that may provide for higher quality of service, survivorship capacity, and reconfiguration capability is a feature of modern grid architecture. The reported research is aimed at delivering a possible, constructal solution that is based on a minimum-redundant, scalable, reconfigurable topology that helps increasing the grid immunity to faults. We assume that a tree network serves nodes of consumption that are evenly distributed throughout the territory. All nodes are equally important and network survivability means delivering electrical energy to as many consumers as possible. The models and loads estimation is based on the load momentum method.

441 two sheets summary

443 Performance comparison of an alternative converter for wind powered switched reluctance generators
Oliveira, E.S.L., Fleury, A., Fleury-Neto, G.A.C., Oliveira, T.F.
Laboratório de Máquinas Elétricas da Universidade Católica de Goiás. Brasil

The subject of this paper is a comparison of the performances of two converter topologies for Switched Reluctance Generators - SRG. It deals with this special electrical generator excited through a rectified DC link. The prime mover is a wind turbine. Mathematical model and simulation results are presented. Both the power converters topologies implemented work well but the alternative one is cheaper and more efficient than the conventional half-bridge one. Furthermore, only the alternative converter allows to feed the load from the grid even when the SRG is not running. This is good for complementary wind power. Experimental results are presented. It was shown that the SRG worked as expected and that the alternative topology reached expectations.

444 About phases dependence in switched reluctance generator
Dias, R.J., Coelho, A., Fleury, A.
Departamento de Engenharia de Universidade Católica de Goiás (UCG) Brasil

This paper analyses and discusses the phase's dependence of the switched reluctance generator - SRG. A 6x4 SRG prototype was assembling for tests. Each one of this SRG phases can be connected and disconnected when needed. A reduced switches count converter that was use to drive the SRG. Experimental results showed changes in the characteristics wave forms of two operational phases when the third phase is disconnected. At a first sight, it was an unexpected result [1], [2]. Although many tests were conduced confirming the first result. Therefore, it should be say that for the prototype tested under the conduced testing conditions each phase behavior depends in the other phases behave. Remarkable changes in the waveforms those are present here. They show that there is not independence between the phases but a truly strong dependence among them.

446 Statistical inter-comparison study of empirical models to estimate the monthly-average daily global irradiation on tilted south oriented surfaces
A. Ramiro(1), F.J.Moral(2), F.J.Masa(1), A. Sordo(1)
(1). Department of Applied Phisics. Extremadura University. Spain
(2). Department of Graphical Expression.Extremadura University. Spain

Determinations of the global irradiation on tilted surface are a prerequisite in different solar applications. Validation of models to estimate such values is of paramount importance, given the limited number of meteorological stations capable of providing such information. Using the global irradiation on horizontal surface recommended in the Schedule of Conditions System Technologies, four models were investigated: Liu and Jordan, Aláiz, Klein and Censolar. A comparative study based on the statisticians of the distribution of the calculated information indicates that the model of Aláiz agreed well with the reference dates. On the contrary, the Censolar has got the maximum diversion.

450 Optimal design of a PV-wind system for water pumping
José L. Bernal- Agustín, Rodolfo Dufo- López, José A. Dominguez Navarro, José M. Yusta-Loyo
Electrical Engineering Department. University of Zaragoza. Spain

This paper shows the optimization of a PV-Wind system to supply the demand of water pumping in a small town in Bolivia. This work has been done with the HOGA program (Hybrid Optimization by Genetic Algorithms). The objective function to minimize in the design process is the total Net Present Cost (NPC) of the system. The system is defined as a combination of components (PV panels and wind turbines). In this case HOGA has used as an enumerative method of design, evaluating all the possible solutions to the design problem.

468 Combined operation of UPQC and fuel cell with common DC bus
S.A.Ale-Emran(1), M. Forghani(2), M. Abedi(1), G.B. Gharehpetian(1)
(1). Electrical Engineering Department, Amirkabir University of Technology, Tehran. Iran
(2). Department of Electrical and Computer Engineering, Tehran. Iran

In this paper analysis results of a cooperation of the unified power quality conditioner with the fuel cell units are presented. A comprehensive control strategy is introduced to extract the compensating signals for the control of the proposed system. The used control strategy can extract the reference currents and voltages of UPQC fast and accurately in the presence of harmonics and/or frequency oscillation. The proposed scheme can compensate voltage sag, voltage interruption and harmonics at the Point of Common Coupling (PCC) on power distribution system. The simulation results prove the efficiency of using the presented method on power quality improvement.

473 Alternative methods for internal arc tests on 12 kV and 24 kV metal-enclosed switchgears with compact RMU
George Curcanu, Constantin Ilinca, Ilie Sbora
ICMET. Craiova. Romania

475 Analysis the islanding mode of combined operation of DG and UPQC in unbalanced distribution system
S.M-Ale-Emran, H.R.Baghaee, M.Abedi, G.B.Gharehpetian
Electrical Engineering Department, Amirkabir University of Technology, Tehran. Iran

The proposed system consists of a series inverter, a shunt inverter, and a Distributed Generation (DG) connected in the dc link. It focuses on improving the power quality and ensuring the continuity of the electric power supply. The function of the scheme has been investigated in islanding mode which is a challenging mode of UPQC. The formulation of the proposed control scheme which is based on the instantaneous power theory is described. The proposed system can improve the power quality at the point of installation on power distribution systems or industrial power systems. Compensation of reactive power at the Point of Common Coupling (PCC) is examined. The effectiveness of the proposed scheme has been verified by simulation.

490 Making the power system intelligent
Péter Kádár
Budapest Tech. Dept of Power Systems. Hungary

The increasing power demand requires better exploitation of the existing system. A possible method is the decrease of the peak/valley ratio of the daily load curve. The local intelligent applications in the households help the control on the power system level. We dig in depth, how the intelligence of lower levels could be raised. The traditional ripple control can not be extended on a lot of programmable household appliances, as the washing machine, refrigerator, tumble drier, etc. We investigated typical households and found a great voluntary control potential. The paper presents the measurement results and gives a HW structure to take these loads into a "smooth" DSM.

490 two sheets summary

502 A control method of parallel inverter for smart islanding of a local power system
Mashahide Hojo(1), Kota Amo(1), Toshihisa Funabashi(2), Yoshinobu Ueda(2)
(1). The University of Tokushima, Japan
(2). Meidensha Corporation, Japan

Various types of distributed generators based on renewable energy become available today. The trends can make some small-scale power networks stand alone with an individual style and benefits, which is referred to as a concept of microgrid. To achieve its stable operation, a parallel inverter which is installed at the coupling point of the microgrid and utility can provide good performance. This paper deals with a control system of the inverter to keep high power quality by supporting the operation of islanding microgrid. The proposed system is tested under various situations including the condition of distributed generator with simulation studies.

502 two sheets summary

503 Sampling frequency and time window influence on flicker measurements significance. A case study.
F. Oliveira(1,2), A. Madureira(3), M.P. Donsión(4)
(1). School of Technology and Management Polytechnic Institute of Leiria. Portugal(2). INESC Coimbra. Portugal
(3). INESC Porto. Portugal
(4). Electrical Engineering Department. Vigo University. Spain

504 New efficient design for air-air heat pumps
C.J. Renedo(1), A. Ortiz(2), M. Mañana(2), F. Delgado(2), S. Pérez(1), D. Silició(2), F.Ortiz(2)
(1). Department of Electrical and Energy Engineering, ETS Náutica, University of Cantabria, Santander, Spain.
(2) Department of Electrical and Energy Engineering, ETSI Industriales y Telecomunicación, University of Cantabria, Santander, Spain

505 Energy implications of the mycosphaerella sp. in eucalyptus globules stands
C.Tejedor(1), S. Pérez(2), C.J. Renedo(2), A. Ortiz(2), M. Mañana(2), D.Silió(2)
(1). Bosques 2000, S.L., Grupo Sniace, Ganzo, Torrelavega, Spain.
(2). Department of Electrical and Energy Engineering, ETSI Industriales y Telecomunicación, University of Cantabria, Santander, Spain

506 Metodology for harmonic distortion level determination
L.I. Eguiluz, J.C. Lavandero, M. Odrizola, V:M. López
Department of Electrical Engineering, Catabria University. Spain

508 An assessment of renewable energy generation in a conventional steam power plant with geothermal feedwater preheating
Janusz Buchta
Technical University of Lodz. Institute of Electrical Power Engineering. Lozd. Poland.

Hybrid steam power plant with geothermal feedwater preheating enables conversion of low temperature geothermal resources into electricity. The paper presents results of calculation of some performance parameters for 200 MWe fossil power unit associated with geothermal well. The paper gives separation rule of renewable energy from conventional one at hybrid power plant output. An influence of geothermal fluid temperature on hybrid power plant performance is discussed in a study and illustrated in several charts.

512 Analytical modelling and implementation of a new four-switch hybrid power filter topology.
Jiri Klima(1), Jiri Skramlik(2), Viktor Valouch(2)
(1). Department of Electrical Engineering and Automation Technical Faculty of CZU in Prague. Czech Republic
(2). Institute of Thermomechanics, Academy of Sciences of the Czech Republic.