PRODUCCIÓN CIENTÍFICA


2017


Election of variables and short-term forecasting of electricity demand based on backpropagation artificial neural networks

Xavier Serrano-Guerrero, Ricardo Prieto-Galarza, Esteban Huilcatanda, Juan
Cabrera-Zeas
Universidad Politécnica Salesiana
Cuenca, Ecuador

Guillermo Escrivá-Escrivá
Institute for Energy Engineering
Universidad Politècnica de Valencia
Valencia, España

Abstract

Forecasting of electricity demand is a fundamental requirement for the energy sector since from its results important decisions are taken. The areas involved are maintenance of electrical networks, demand growth, increased installed capacity, among others, whose lack of precision can take high economic costs. In this work, we propose a method based on backpropagation neural networks and election of key variables as inputs. The number of neurons in the hidden layer was optimized. To avoid the overtraining the best time range of data was defined. The results show that the method works particularly well for short-term forecasting (24 or 48 hours).

Classification of Partial Discharge in Pin Type Insulators Using Fingerprints and Neural Networks

M. Quizhpi-Cuesta, F. Gómez-Juca, W. Orozco-Tupacyupanqui, F. Quizhpi-Palomeque

Universidad Politécnica Salesiana Sede Cuenca
Cuenca, Ecuador

Abstract

The classification of partial discharge (PD) or partial breakdown (PB) is an important issue that helps to identify the cause of this electrical phenomenon in pin type insulators. In this work, a PD classification method based on neural networks (NN) is proposed. This sorting technique consists of three parts. First, the detection and measurement of partial discharge are achieved by using a digital finite impulse response (FIR) filter, whose main objective is to obtain electrical charges with significant characteristics of the PB. The second part of the process deals with the classification of partial discharge. A statistical analysis is implemented to obtain PD patterns or fingerprints which are classified by a neural network. Finally, the third part of the proposed method focuses on interpreting the information obtained from the NN and determining the PD current in the pin isolator. The results show that this proposed technique of analysis and detection of partial discharge in pin type isolators is successful in optimizing the time of analysis and classification of PB.

A digital control system for Lighting Energy Consumption Efficiency (LECE)

F. Pesántez-Pesántez, A. Valdez-Salamea
X. Serrano-Guerreo, W. Orozco-Tupacyupanqui
Universidad Politécnica Salesiana
Cuenca, Ecuador
{fpesantez, avaldez}@est.ups.edu.ec
{jserrano, worozco}@ups.edu.ec

G. Escrivá-Escrivá
Institute for Energy Engineering
Universidad Politécnica de Valencia
Valencia, España
{guieses}@die.upv.es

Abstract

In this article, a digital control systems for Lighting Energy Consumption Efficiency (LECE), based on a proportional-integral-derivative (PID) controller, is proposed. In this approach, the designed microcontroller system interacts with natural lighting and controls led light bulbs. In this sense, this system is able to automatically reduce, in a smart appropriate manner, the consumption of energy without affecting the comfort of people visualization. The proposed system was tested during three months and located in four physical spaces at Universidad Politécnica Salesiana (UPS) in Cuenca. In order to perform a quality analysis of the smart system, three items were selected to study: illumination, luminance and consumed electrical power. According to the results, the electronic system was able to save approximately 70% of lighting energy consumption.

Measurement of Internal Partial Discharges in Dielectric Oils by Applying the Electrical Method

Jaime A. Torres-Arias, Cristhian M. QuezadaViñanzaca, Diego P. Chacón-Troya, Flavio Quizhpi-Palomeque

Universidad Politécnica Salesiana Sede Cuenca
Cuenca, Ecuador

Abstract

This document details of the conventional electric method for measuring partial discharges (DP) based on the norm IEC 60156, various test were performed on dielectric oils which had different qualities, the test results were processed through MATLAB's signal processing filters in conjunction with fast fourier transform (FFT) in order to determine the type of partial discharge based on the quality of the dielectric oil and it's contamination level.

Calculation of the earth resistance of the union of two and three rods by modified Schwarz equations and field tests

S. Freddy M. Sinchi, P. Flavio A. Quizhpi, C. Hernán P. Guillén

Universidad Politécnica Salesiana Sede Cuenca
Cuenca, Ecuador

Abstract

This report discloses the modification of the Schwarz equations presented in the IEEE 80-2013 standard, in order to calculate the ground resistance of two and three rods connected in line, and three rods connected in triangle. The implementation of these designs is carried out in several soils with different resistivity values, to proceed to measure the resistance of grounding and to check with the theoretical calculation.

Simulation of harmonics produced by electroliners in the electrical network of Cuenca City

Cristian Enriquez, Diego Chacón-Troya, Hector Romero, Flavio Quizhpi

Universidad Politécnica Salesiana Sede Cuenca
Cuenca, Ecuador

Abstract

This article presents the simulation and harmonic analysis of a charging station model developed in “Modeling and protection of electric vehicle charging station”, which was adapted with the electrical parameters of the distribution system of Cuenca city, with The purpose of quantifying the amount of harmonics that this type of stations can produce in the network. The simulation resulted, that the fifth harmonic located at 300 Hz is the most critical in both the voltage and the current. The harmonics produced in the voltage are 15, 74% that are above the limits established in the IEEE 519-2014 standard and the Ecuadorian regulation No. CONELEC-004/01, the harmonics produced in the current are of the order of 1.54% that is within the parameters of the IEEE 519-2014 standard. The results of this research can be used to mitigate the impact and can be used by designers and builders of charging stations and for energy distribution companies.

Active power filter with current balancing capability for two-phase systems

Julio Viola†, Marco Fajardo‡, Jos´e Manuel Aller†, Jos´e Restrepo‡, Flavio Quizhpi†
†UNIVERSIDAD POLITECNICA SALESIANA, ‡UNIVERSIDAD SIM ´ ON BOL ´ ´IVAR
†Calle Vieja 12-30 y Elia Liut, Cuenca, Ecuador
‡Valle de Sartenejas, Baruta, Caracas, Venezuela
Phone: +593 (7) 286-2213
Email: jviola@ups.edu.ec
URL: http://www.ups.edu.ec

Abstract

Two-phase residential installations have become very common in Ecuador since different policies prompt the users to replace gas stoves and water heaters by electric appliances. The addition of a second phase to the originally installed single-phase wiring is required to obtain 220Vrms. This fact carries an intrinsic unbalance since single- and two-phase loads coexist. In this paper a topology for an active power filter is proposed which is able of balancing of the currents leading to a balance in the active power in each phase. This added feature does not interfere with the capability of the active power filter for reactive power compensation. The proposed topology is tested by simulations for two-phase systems having phase voltages with 120° and 180° of difference.

AHP analysis to minimize the effects produced by the textile industry in the rivers of Cuenca city. Determination of the better alternative to mitigate water pollution.

Jaime A. Torres A.  Gabriela L. Carrión V. Cristhian M. Quezada V. Cesar I. Coronel Z.

Edgar A. Barragan E..
Profesor Titular Auxiliar 1 Carrera Ingeniería Eléctrica
Universidad Politécnica Salesiana Sede Cuenca
Cuenca, Ecuador
ebarragan@.ups.edu.ec

Abstract

In this study, the current environmental situation of the rivers of Cuenca city was analyzed, as well as the threats presented by the textile industry to the environment, due to the city is crossed by 7 rivers, which are directly affected by this industry. For its analysis the AHP method has been implemented to determine the most optimal solution to the contamination suffered by these affluent.

An Alternative Method for Partial Discharges Measurement Using Digital Filters

M. Quizhpi-Cuesta, F. Gómez-Juca, W. Orozco-Tupacyupanqui, F. Quizhpi-Palomeque, Member IEEE
Universidad Politécnica Salesiana, Cuenca, Ecuador
{fquizhpic, fgomezj}@est.ups.edu.ec, {worozco, fquizhpi}@ups.edu.ec

Abstract:

Partial Discharge (PD) or Partial Breakdown (PB) analysis is one of the most widely used methods to determine the state of electrical power insulation systems. An alternative method to measure PD is presented in this paper. In this proposed approach, data are obtained from electrical charge signals displaced by partial discharges on dielectric elements, pin type insulators. An electrical assembly consisting of a high voltage (HVAC) source, a blocking impedance, a capacitive divider and a measurement impedance was designed to obtain data. The signal detected by the measurement impedance is displayed on a high-end oscilloscope, the visualization instrument has the possibility of accessing the management software; therefore, it was possible to implement a bandpass finite impulse response (FIR) digital filter of a higher order than one hundred. The output of the filter presents the components of typical signals in partial discharges produced inside the dielectric material. Different analyzes were performed by using data segmentation which allows affirming that this approach is valid for its implementation. It this case, this method is innovative and appropriate for application in laboratories where there does not exist PD analyzers.

 

Back-to-Back Active Power Filter for Current Balancing in Two-Phase Systems.

Viola, J., Fajardo, M., Aller, J. M., Quizhpi, F., Restrepo, J., & Ginart, A. (2017, March).  In Green Technologies Conference (GreenTech), 2017 Ninth Annual IEEE (pp. 139-144). IEEE.

Abstract

The use of a second phase in household electric wiring is a requirement for feeding heavy loads in those countries using 100 ∼ 127 Vrms as the standard voltage. One problem of this wiring is the unbalance between phase currents since single- and two-phase loads coexist. A back-to-back topology is proposed for an active power filter to add it the ability of active power compensation. The presented topology uses the same number of hardware components of others proposed topologies that just are able of reactive power compensation. The system is tested implementing a predictive direct current control when is connected to two different two-phase systems: those obtained by taking two phases of a three-phase system (120◦ between phases) and for two phases obtained from a split-phase transformer secondary (180◦ between phases).

DIO:  10.1109/GreenTech.2017.26

 

Electricity production using renewableresources in urban centres

Antonio Barragán-Escandón MSc
Department of Electrical Engineering, Universidad Politécnica

Julio Terrados-Cepeda PhD
Department of Graphic Engineering, Design and Projects, Universidad
de Jaén, Jaén, Spain

Esteban Zalamea-León PhD
Facultad de Arquitectura y Urbanismo, Cuenca, Ecuador

Pablo Arias-Reyes MSc
Laboratorio de redes inteligentes, Ingeniería Eléctrica, Universidad
Católica de Cuenca, Cuenca, Ecuador

Abstract

Previous research has identified 11 technologies that use resources that are available in or come from cities. It has been established that using these technologies, the flows from energy carriers required by cities could be reduced. These carriers can be electricity or fuels. Of the identified technologies, eight can produce electricity: biomass, biodigestor biogas, landfill biogas, waste incineration, tidal, small wind, small hydroelectric and photovoltaic technologies. The use of these technologies depends on the existence of resources and technical, economic and social or environmental factors. This research proposes the use of multiple-criteria techniques to select the most appropriate options for promoting renewable energy in cities. This approach was applied to the medium-sized city of Cuenca in Ecuador. Ecuador is a developing country, is an oil producer and has important water resources. The authors concluded that studies of the potential for implementing hydroelectric and solar photovoltaic energy and energy from landfill gas should be extended. The results coincide with the existing resources, implemented projects and the expectations of local professionals.

Experimental evaluation of the voltage unbalance in the efficiency of induction motors

Johnny Rengifo ∗†, Henryke Salazar∗, Alexander Bueno∗ and José M. Aller∗‡
∗Universidad Simón Bolívar, Caracas–Venezuela
Email: {jwrengifo,bueno}@usb.ve
†Universidad Central de Venezuela, Caracas–Venezuela
‡Universidad Politécnica Salesiana, Cuenca–Ecuador
Email: jaller@ups.edu.ec

Abstract

This paper presents an experimental evaluation of the voltage unbalances effects in the efficiency of induction motors. In that sense, two distinct National Electrical Manufacturers Associations (NEMA) design were evaluated to seek the changes on their performance. The voltage unbalance was assessed using the Complex Voltage Unbalance Factor (CVUF). The experimental methodology consisted in a segregation losses approach to study the stator, core, friction, rotor, and stray-load losses clearly. First, a no-load test was carried out in both motors keeping constant the magnitude and the angle of CVUF. Next, a load test was accomplished ranging the mechanical load from 120% down to 30% of the nominal load using the same CVUF of the no-load test. Finally, according to the results of NEMA design B motor has the greatest losses increment because it was the most affected by the skin effect.


 

Health Index Assessment for Power Transformers with Thermal Upgraded Paper up to 230kV, Using Fuzzy Inference. Part II: A Sensibility Analysis

Diego P. Chacón -Troya, Member, IEEE, Juan Pablo Lata, and Ricardo D. Medina

Abstract:

This paper presents a sensitivity analysis of a health index of power transformers tool, in order to identify the importance of each input to determine most important and those that can be dismissed to simplify the calculation process without significantly affecting the effectiveness of answers. To achieve objective, a methodology based on a study case is proposed which, starting from a set of real scenarios, analyzes the variation of the output (health index) when each input (tests performed in oil) is varied.

 

 Implicit PV Cell Parameters Estimation used in Approximated Closed-Form Model for Inverter Power Control

Jose Aller∗† Julio Viola∗ Flavio Quizhpi∗ Jose Restrepo† Antonio Ginart‡ Andres Salazar§
∗Universidad Politécnica Salesiana – Departamento de Ingeniería Eléctrica – Cuenca – Ecuador – jaller@ups.edu.ec
†Universidad Simón Bolívar – Departamento de Electrónica y Circuitos – Caracas – Venezuela – restrepo@usb.ve
‡Kennesaw State University – Deparment of Electrical Engineering – Atlanta – USA – aginart@kennesaw.edu
§University of Georgia – Deparment of Electrical Engineering – Atlanta – USA – andres.salazar@ece.uprm.edu

 

Abstract

This paper evaluates the use of a Photo Voltaic (PV) parameter estimation method based on implicit optimization algorithms and its use in power controller strategies by explicit model representation obtained with First and Second Order Approximation Models (FOAM, SOAM). An explicit function linking voltage, current and power of PV) cells is presented
using the parameters obtained during the implicit estimation.
The proposed method gives direct analytical solutions, resulting from a truncated Taylor series for the single diode PV-model. The analytical equations are easier to put into practical use and give solutions with an equivalent precision similar to the numerical method (Newton-Raphson Method) for the PV’s cell voltage produced under particular conditions of temperature and solar radiance. The main benefit of this set of equations, useful also for optimal voltage estimation, is that offer an accurate and simple determination of the voltage profile using the manufacturer’s data-sheet and PV plant’s location for an specific design. The verification of the proposed method uses information from the manufacturer’s datasheets of 12 different PV cells. The comparison of the results, for the analytical expressions versus the Newton-Raphson solution, validates the proposed method. Index Terms—PV model, parameter estimation, closed-form representation, Taylor expansion, no-linear optimization.

Parameter Estimation for Deep-Bar Induction Machines Using Instantaneous Stator Measurements From a Direct Startup

Joseph Benzaquen, Student Member, IEEE, Johnny Rengifo, Eduardo Alb´anez, and Jos´e M. Aller

Abstract

A parameter estimation method for deep-bar induction machines is presented. The parameters are estimated using two instantaneous voltage and current waveforms during a direct startup. The instantaneous input impedance is used as a stator indicator to solve a constrained nonlinear optimization problem that outputs the model’s parameters. For such purposes, a novel analytical expression for the instantaneous input impedance is introduced. The method is validated in two distinct National Electrical Manufacturers Association (NEMA) design type induction machines (designs A and B), and the accuracy of the obtained parameters is determined by comparing the instantaneous input impedance magnitude and angle errors between the deep-bar and single-cage models with experimental data. The two tested motors showed an improvement when implementing the deep-bar model with the estimated parameters. The error decrease is more significant for the NEMA design B motor which corresponds to a deep-bar rotor construction. Finally, the single-cage and deep-bar models are simulated and their outputs are compared to experimental waveforms. The deep-bar model with the estimated parameters outperforms the single-cage model, showing excellent agreement between the experimental and simulated mechanical speed, stator currents, and electromagnetic torque. The results endorse the accuracy of the method and its applicability for transient studies.


2016



An Approach to Develop a LabVIEW based Augmented Reality Application for Smartphones

Ernesto Granado Migliore
Universidad Simón Bolívar, Caracas, Venezuela
granado@usb.ve

Julio Zambrano Abad  Flavio Quizhpi Palomeque
Universidad Politécnica Salesiana Cuenca, Ecuador
{jzambranoa, fquizhpi}@ups.edu.ec

Abstract:

This paper presents an approach to develop a smartphone augmented reality application for automation and control education. This approach is based on the client/server architecture. On the server side, the standard academic research software LabVIEW platform is used for real time pattern recognition processing, enabling the quick augmented reality application creation. Adobe Flash technology is used to get a well-designed friendly graphical client interface. The employment of this application provides students in an amusing and straightforward way, all the information they required to both facilitate and increase their learning process. The computergenerated content that overlays the real-world environment is relates to the laboratory practices and equipment. Besides that, this application has incorporated innovative features that make augmented reality sensible, not only by the real-world environment, but also by the date it is being used. In other words, supplementary computer-generated content may vary according to the date the student uses the application.


An Approach to Develop a Virtual 3D Stereoscopic Environment for Smartphones

E. Granado, J. Viola, J. Zambrano and F. Quizhpi.

Abstract:

This paper presents an approach to develop an immersive virtual three-dimensional stereoscopic environment for control education. Thanks to the technological advances and the actual continuous reduction costs on electronic devices, it is possible to create immersive 3D virtual scenarios applying the side-by-side technique; and using standard gadgets like: smartphones, and head-mounted displays. Due to the smartphone built-in accelerometer, the user can easily and intuitively control the movements around the virtual world. Also, the Wii-remote® is used as an auxiliary input device to interact with the application. The proposed method permits to interact and visualize three-dimensional virtual scenarios without the need of specialized software or browser-plugins installed in the smartphone. By taking advantage of today’s smartphone technological features, students fee highly motivated to use this device as an amusing learning tool. Since this application resembles three-dimensional computer games, it attracts students, increases their concentration, and keeps their attention during the learning process.


Analysis and Simulation of Fault Tolerance of a Grid-connected PV Inverter by Z-source Impedance

Diego P. Chacón-Troya_1, Christian Jara Alvarez _1, Enrique Galarza Pablo1 and José Manuel Aller_1_2
1_Universidad Politécnica Salesiana, Cuenca, Ecuador
2_Universidad Simón Bolívar, Caracas, Venezuela

Abstract:

This paper proposes the design of a monophasic inverter connected to a residential network by applying ZSource topology. The proposed models were verified in normal operation “STC” and under short circuit conditions “SC”. The system is presented as coupled to a network without a transformer and with minimum electrical components. The tolerance of the overcurrent or short-circuit current is also analyzed on this topology. The signal’s power is conditioned to find the MPP of the PV panels. Its architecture will be outlined, described and simulated in Matlab’s Simulink®. In order to verify that the design is working properly.


Current Control For a Grid-connected Inverter Operating With Highly Distorted Grid Voltage

Julio Viola†, José Restrepo‡, José Manuel Aller‡ and Flavio Quizhpi†
Universidad Politécnica Salesiana Cuenca, Ecuador, EC010105
Email: jcviola@ieee.org
†SENESCYT – Prometeo Project, Ecuador
‡Universidad Simón Bolívar, Caracas, Venezuela, 1080A

Abstract:

Grid-connected inverters are an essential component of modern photovoltaic systems. They allow the users to obtain a faster recovery of the investment given their capability of injecting the excess of generated energy to the grid. Proper operation of the inverters requires a current loop with the capability to deal with eventually distorted grid voltages and with LCL coupling filters. This makes the control much more sensitive to errors or delays in the values of the control variable. In this paper a real-time digitally implemented technique is proposed to obtain a reconstructed version of grid voltage which can be used as a feedforward signal in the current loop of a grid-connected inverter.


Design and Testing of Toroidal Coil for Induction Water Heater

Luis F. Quevedo, César G. Mancheno, John A. Morales, Flavio A. Quizhpi.
Carrera de Ingeniería Eléctrica, Universidad Politécnica Salesiana sede Cuenca – Ecuador.

Abstract

Based on the change of the productive and energetic matrix o Ecuador, that consist in the substitution of liquid gas coming from black oil for electricity to cook food and water heatin  for human use in residential areas, a prototype Toroidal Coil (TC) for a water heater Magnetic Induction (MI) is presented in this article.

Its operation is rooted in an inverter DC-AC in Sinusoidal Pulse Width Modulation (SPWM) used for driving high frequency waves thru the winding of the coil, generating resistive losses transmitting heat to the hydraulic fluid the moment that this fluid gets in contact with the core coil the ferromagnetic implemented. This way it is insured the maximum heat transfer, showing that the magnetic fields generated by this prototype are within the standards issued by the ministry of environment regarding the levels of electromagnetic fields to which people is exposed in this case due to the fields produced by the TC.


Design Of Current Control Loop For Grid Connected Inverters Operating Under Nonideal Grid Conditions

Julio Viola ∗†, José Restrepo ‡, José Manuel Aller †‡, Flavio Quizhpi ∗, and Marco Fajardo ∗
∗ Universidad Politécnica Salesiana Cuenca, Ecuador, EC010105
Email: jcviola@ieee.org
† SENESCYT – Prometeo Project, Ecuador
‡ Universidad Simón Bolívar, Caracas, Venezuela, 1080A

Abstract:

A case study for designing the current control loop for single-phase inverters connected to weak grids is presented. The problems associated to the design of current control loop when highly distorted grid voltages are present and LCL filters are used to couple the inverters to the grid, are analyzed. Fourier coefficients decomposition is used to obtain an aheadof- time version for the nonideal voltage signal which allows to compensate the current control loop delay. Also the relevance of
nonideal characteristic of the inverter as the dead-time effect on the shape of the controlled current is analyzed and compensated.


Enhanced Placement of Fault Locators on Overhead Distribution Networks (Ubicación Mejorada de Localizadores de Falla en Redes de Distribución Aéreas)

D. X. Morales, Member IEEE, D. Icaza, P. Flores, F. Conce, G. Conce,
R.D. Medina, Member IEEE, W.P. Borja, Student Member

Abstract:

This paper aims to determine and identify the best technical placement for fault locators –FLs- on the distribution network, in order to improve the reliability in the system. The international indices such as SAIFI and SAIDI are evaluated in two scenarios; the first one analyze the power system in its current configuration whereas the second one assumes that FLs are installed in different places. A case study composed of three feeders from Galapagos Islands is analyze, considering different cases with one, two and three FLs.


Explicit Model of PV Cells considering Variations in Temperature and Solar Irradiance

Jose Aller† Julio Viola Flavio Quizhpi Jose Restrepo† Antonio Ginart‡ Andrés Salazar§
Universidad Politécnica Salesiana – Cuenca – Ecuador
†Universidad Simón Bolívar – Caracas – Venezuela
‡Kennesaw State University – Atlanta – USA
§University of Georgia – Atlanta – USA

Abstract:

This paper presents a direct and approximate model of PV cell that considers variations in surrounding temperature and solar irradiation. The method uses the one diode model approximation and PV parameters from the manufacturer’s data, together with a selective (first or second order) Taylor series. In this paper, a recursive solution for the PV cell’s complete implicit model equations supplies data supporting the proposed approximate method results. The proposed model allows adjustment of the MPPT algorithm to simplify in real time the inverter control algorithm. It also provides a way to find the temperature and solar irradiation or errors produced by nonuniform irradiation on the solar panels.


Hybrid control scheme for the current loop of a grid connected inverter operating with distorted grid voltage

Julio Viola∗†, José Restrepo‡, José Manuel Aller∗†‡ and Flavio Quizhpi†
∗ Universidad Politécnica Salesiana Cuenca, Ecuador, EC010105
Email: jcviola@ieee.org
†SENESCYT – Prometeo Project, Ecuador
‡Universidad Simón Bolívar, Caracas, Venezuela, 1080A

Abstract:

The complete design of the current control loop for single-phase inverters connected to weak grids is presented. The problems associated to the design of current control loop when highly distorted grid voltages are present and LCL filters are used to couple the inverters to the grid, are analyzed. Fourier coefficients decomposition is used to obtain an aheadof-time version for the nonideal voltage signal which allows the compensation of the current control loop delay. Also the relevance of nonideal characteristic of the inverter as the deadtime effect on the shape of the controlled current is analyzed and compensated. Simulations and experimental results are included for the proposed methods.


Impact Assessment of New Services in the Galapagos Low Voltage Network

D. X. Morales, Y. Besanger, C. Alvarez Bel R.D. Medina
Diego.Morales-Jadan@g2elab.grenoble-inp.fr Yvon.Besanger@g2elab.grenoble-inp.fr CALVAREZ@upvnet.upv.es rmedinav@ups.edu.ec

Abstract:

The Galapagos Islands are a fragile ecosystem which belongs to Ecuador. About 26.000 people are located in four islands of the archipelago and 60% of the population is concentrated on Santa Cruz Island. Combined technologies are used for providing electricity such as thermal, photovoltaic and wind. The government of Ecuador is fostering the policy zero CO2 emissions within the islands. In order to achieve this objective, some initiatives are carried out like replacing the conventional vehicles by electrical ones and the gas stoves by induction ones. Taking into account this framework, it becomes vital to assess the impact of these new policies on the distribution network; for sure, this will change significantly the operation and control of Galapagos distribution grid. Hence, strong integration of distributed generation, electric vehicles, and induction cookers must be assessed at the low voltage level, where they are usually connected.

This paper assesses the impact of all the new services on the low voltage network as well as the new electric demand due to natural population grow. Real field information has been used in the models presented


Impact Study of New Loads and Time of Use Schedule in the Low Voltage Network

D. X. Morales, Y. Besanger, M. Toledo R.D. Medina
Diego.Morales-Jadan@g2elab.grenoble-inp.fr Yvon.Besanger@g2elab.grenoble-inp.fr mtoledo@centrosur.gob.ec rmedinav@ups.edu.ec

Abstract:

Nowadays, the distribution networks are facing with new challenges such as the electrical vehicle connection, the emergence of new charges such induction cookers especially in South America and a strong integration of distributed generation at the low voltage level. In addition, the costumers are transforming their habits in order to become much more active in the network. Hence, this paper assesses the impact of new load/generation connected at low voltage as well as proposes a demand side management technique in order to try to reduce the main power peak during the night. The authors use real information coming from measurements.


Inversor multinivel acoplado sin transformador a la línea eléctrica para la incorporación de fuentes fotovoltaicas distribuidas

Julio César Viola1, , José Restrepo-Zambrano2, José Manuel Aller-Castro2 y Flavio
Quizhpi-Palomeque1

Abstract:

El presente trabajo trata sobre el estudio, diseño e implementación de un inversor multinivel capaz de operar con los esquemas de distribución eléctricos más comunes en el Ecuador y que pueda ser acoplado a la línea sin necesidad de transformador. Su control incluye la posibilidad de revertir los flujos de potencia en caso de ser necesaria la carga de bancos de batería. El trabajo presenta los pasos seguidos en el diseño así como las simulaciones de funcionamiento y resultados experimentales preliminares.


Power Transformers Risk Index Assessment in the Ecuadorian Context (Evaluación del Índice de Riesgo de Transformadores de Potencia en Concordancia con el Contexto Ecuatoriano)

K. C. Bustamante, Student Member, IEEE, W. P. Borja, Student Member, IEEE, B. B. Miranda,
Student Member, IEEE, L. A. Zhunio, Student Member, IEEE, and R. D. Medina, Member, IEEE,

Abstract:

Economic losses in the power transformer parks are a consequence of a careless administration of assets. In this work, the parameters considered during the power transformer risk evaluation are presented. Asset management involves a deep analysis and strategies to prevent major failures or malfunctions. A comparison of the procedures to asses risk index of the power transformers is presented. At the end of this work, the more utilized parameters in the health index study, probability of failure, and the consequence of the power transformers are compared according different authors.


Remote Experimentation Using a Smartphone Application with Haptic Feedback

Ernesto Granado,  Flavio Quizhpi.  Julio Zambrano William Colmenares
Universidad Simón Bolívar, Caracas, Venezuela. Universidad Politécnica Salesiana, Cuenca, Ecuador

Abstract:

This paper presents the development of a remote experimentation for automatic control engineering education. By using a smartphone application, students can interact with real laboratory didactic equipment. Through a friendly graphical user interface and information provided by built-in smartphone sensors, students can modify the process parameters and verify in real time what’s happening on the experimental setup. Mobile device vibration technology is used to add haptic tactile feedback to the application. This additional sense complements the visual and hearing information the user usually acquires when performing a practical experience. Therefore, students pay more attention to the results achieved online. Taking advantage of today’s smartphone technological features, the students feel highly motivated to use this device to achieve improvements in their learning process. To reach a great number of users, the application runs across the most widely used mobile platforms. All user lab activities are stored in a database for the teacher later analysis. Likewise, students can store the resulted experiments on their mobile device when finished in order to make an off-line result analysis.


Robust Multivariable PID Control for Quadruple- Tank Process Using an ILMI Approach

Diego Mogrovejo1, Ernesto Granado2,3,4, William Colmenares2, Julio Zambrano4 and Flavio Quizhpi4
1 Universidad Politécnica Salesiana, Maestría en Control y Automatización Industriales, Cuenca, Ecuador
2 Universidad Simón Bolívar, Caracas, Venezuela
3 Prometeo Project Researcher-SENESCYT, Ecuador
4 Universidad Politécnica Salesiana, Cuenca, Ecuador
Email: {dmogrovejom, jzambranoa, fquizhpi}@ups.edu.ec, {granado, williamc}@usb.ve

Abstract:

This paper shows a robust multivariable PID controller design for a nonlinear quadruple tank process. The controller synthesis is reduced to an equivalent static output feedback control problem. The closed loop β /2 -stabilizable performance is guarantee for the linearized system with convex polytopic uncertainty. The algorithm is based on an iterative linear matrix inequality approach. The Parameter-dependent Lyapunov matrix functions, together with the Lyapunov matrix and the system dynamic matrix decoupling, are used in robust stabilizability conditions for conservatism reduction in the robust problem formulation. The design technique is illustrated with a numerical example.


2015



Banco de Emulación de Perfiles de Viento para Aplicaciones en Energía Eólica

J. Restrepo3 J. Viola 2 F. Quizhpi 1
1 Universidad Politécnica Salesiana 2 SENECYT 3 Universidad Simón Bolívar
Email: restrepo@ieee.org, jviola, fquizhpi@ups.edu.ec

Abstract:

El trabajo presenta el desarrollo de un banco de emulación de perfiles de viento, incluyendo el sistema de conversión de energía eólica a energía eléctrica. El banco completo de emulación consta de un elemento motriz, encargado de proporcionar perfiles par/velocidad, correspondientes a datos reales de disponibilidad eólica de un lugar geográfico particular. El elemento motriz, constituido en este banco de emulación por un motor de corriente continua de 3.3 kW, se acopla al elemento generador, en este caso una máquina de rotor bobinado (DFIG por sus siglas en inglés), de 4.0 kW @ 50 Hz. Las máquinas eléctricas se alimentan a través de un sistema de potencia compuesto por un puente rectificador y un puente H, para la máquina de corriente continua, y un convertidor dual en configuración “back to back” para la máquina de inducción de rotor bobinado. Los elementos conmutadores del sistema de potencia son módulos duales de transistores bipolares de compuerta aislada (IGBT). Se utilizan dos bloques disipadores de calor, uno para el conjunto rectificador/puente-H, y otro para el convertidor dual. La velocidad del eje del conjunto de máquinas se mide utilizando un codificador óptico. Las señales necesarias para el control, del sistema emulador, se miden mediante dos tarjetas de sensores de tensión/corriente, con capacidad para medir 16 señales en total. Para el control de los convertidores se utiliza una tarjeta basada en un arreglo de lógica programable (FPGA) interconectada con un procesador digital de señales (DSP) que permite la alta velocidad de procesamiento requerida para probar distintas técnicas de control. El convertidor es controlado por modulación de ancho de pulso (PWM) conmutando a una frecuencia ajustable, en este caso se selecciona una portadora de 10kHz.


Comparison of the Parameter Estimation for the Induction Machine Dynamic Model using Instantaneous Measurements at Standstill and during Start-up

José M. Aller∗†‡, José A. Restrepo∗†‡IEEE member, Julio C. Viola∗†, Pedro R. Barbecho†,
Johnny Rengifo‡ and Flavio A. Quizhpi†
∗Prometeo – SENESCYT, Quito – Ecuador
†Universidad Politécnica Salesiana, Cuenca – Ecuador
‡Universidad Simón Bolívar, Caracas – Venezuela
email:{jaller, jviola, pbarbecho, fquizhpi}@ups.edu.ec;restrepo@ieee.org; jwrengifo@usb.ve

Abstract:

This work presents a comparison of three techniques for parameter estimation of the induction machine dynamic model. The first estimation method is based on measurements with the rotor at standstill while several single phase voltage sources are applied at different frequencies. The second method is based on obtaining the instantaneous measurements of voltages and currents during a direct start-up in no load or load condition. To validate the results obtained in each one of these tests, conventional estimation methods are applied to a wound rotor induction machine, according to international standards. The estimation methods are verified using simulations. The obtained results will allow to analyze the accuracy of both methods, and their applicability in industrial environments. The analysis shows the practical conditions where each one of these methods can be applied successfully.


Current Controller for Induction Motor using an Artificial Neural Network trained with a Lyapunov based Algorithm

Julio Viola-a,b, José Restrepo-a,b,c, José Aller-a,b,c
a-Prometeo Project Researcher
b-Universidad Politécnica Salesiana Cuenca, Ecuador
{jcviola, restrepo}@ieee.org
cUniversidad Simón Bolívar Caracas, Venezuela
jaller@usb.ve

Abstract:

This paper presents the use of a training algorithm based on a Lyapunov function approach applied to a stator current controller based on a state variable description of the induction machine plus a reference model. The results obtained with the proposed controller are compared with a previously reported method based on a Nonlinear Auto-Regressive Moving Average with eXogenous inputs (NARMAX) description of the induction machine. The proposed Lyapunov based training algorithm is used to ensure convergence of the weights towards a global minimum in the error function. Real time simulations employing a DSP based test bench are used to test the validity of the algorithms and the results are verified by a practical implementation of these controllers.


Developing of a Monitoring and Control System of an Electric Load for Domestic Applications

Diego P. Chacón-Troya, María Fernanda Mena
Universidad Politécnica Salesiana Cuenca, Ecuador
dchacon@ups.edu.ec, mmenas@est.ups.edu.ec

Abstract:

The energy consumption is justified by the man’s need of having a comfortable survival, thus, the production, generation and power management is a clearly relevant and vital fact. This paper describes the development of a prototype system to carry out the measurement, monitoring and control of electrical charge whose application is purely residential, with the aim of not exceeding a certain limit of consumption, this device will handle circuit switching, display and storage of information. Moreover, it can work wired or wireless by using the Zigbee standard. It is important to point out that this paper will focus in the technologies used to develop the mentioned equipment and how they are integrated to obtain the final prototype.


Fractional order PIα controller applied to the induction machine current loop

Miguel Abrilb,  Jose Restrepo a_b_c,  Julio Viola_a_b, Jose M. Allera_b_c , a_Prometeo-SENESCYT, Quito Ecuador b_Universidad Politécnica Salesiana, Cuenca-Ecuador  c_Universidad Simón Bolívar, Caracas-Venezuela
email: ingmiguel abril@hotmail.com, restrepo@ieee.org, {jviola, jaller}@ups.edu.ec

Abstract:

This paper investigates the use of fractional order PIα controllers, applied to inverter driven induction machines. Fractional order controllers provide additional degrees of freedom for their design, and the non-linearity introduced by the fractional part of the controller provides better tuning for the operation of the controller. In this work a fractional PI controller is applied to the current loop of a vector controlled induction machine and the results are compared to the ones obtained with a conventional PI
controller.


Indoor Propagation Analysis Applied In Zigbee Netwoeks

Diego P. Chacon-Troya, Andrea Gracia  Universidad Politecinica Salesiana  Cuenca-Ecuador     dchacon@ups,edu,ec, andreagarciace@hotmail.com

Abstract:

ZigBee technology is a set of devices, and wireless  communication standards for personal area networks, its  operation is based on the IEEE 802.15.4 standard.  In this work the development of a Matlab-based software for the  analysis of indoor coverage of ZigBee networks is presented. This platform is based on the equations of Cost Multi-Wall  propagation model, based on this the location of end devices is  analyzed for devices with routing capability such as coordinators  and routers, imaging processing methods to locate infrastru are  obstacles existing on the wireless link are applied. As a result the  parameters of wireless link, coverage areas are obtained and the  connection status of the elements of a ZigBee network is  evaluated. These results Will be used for the correct location of  the devices on the network with respect to the infrastructure  presented indifferent scenarios of ZigBee technology implementation.

 


Lighting Control Actuator Design and Development for a ZigBee Network with a Web Server Mounted on Raspberry Pi.

Martin V. Urgiles, Paul E. Arpi, Diego P. Chacon-Troya
Universidad Politécnica Salesiana Cuenca, Ecuador
murgiles@est.ups.edu.ec, parpi@est.ups.edu.ec, dchacon@ups.edu.ec

Abstract:

Competitive solutions to the growing demand for home automation will most likely include the use of low cost components, open source and open hardware. Using the ZigBee protocol, a low cost lighting control actuator was developed that was battery efficient and easy to use in a home automation system environment. Raspberry Pi was used to house a Web server, which provided the user an adaptive web application to access the lighting actuator control. XBee modules were chosen for their small size, low energy consumption and the large amount of documentation that exists in regard to its use. Considering the worst-case scenario, the lighting control actuator was designed so if its battery runs out of power or the ZigBee network fails, it can work as a normal light switch.


Modeling a Permanent Magnet Generator and its Controller for a Wind Turbine System

Diego P. Chacon Troya  1 Carlos Mendez_1 Juan Segarra_1 Jose M. Aller 1,2,3
Universidad Politécnica Salesiana, Cuenca, Ecuador 2_SENESCYT, Prometeo, Ecuador
3_Universidad Simon Bolivar, Caracas, Venezuela
dchacon@ups.edu.ec, cmendezm@est.ups.edu.ec, j segarrav@est.ups.edu.ec, jaller@ups.edu.ec

Abstract:

In this paper the results of the dynamic model for a permanent magnet generator and its controller to be used on a wind turbine system are presented. The wind model is conceptually based on the behavior of the power extraction. The permanent magnet machine is modeled in the space vector coordinates using the rotor frame. The power converter realizes the interconnection with the load or the power system. The model results shown a precise adjust of the active and reactive power.


Predictive control of a three-phase power converter coupled with LCL filter

Julio Viola-a,c, José Restrepo-a,b,c, Flavio Quizhpi-c, José Aller-b
a-Prometeo Project Researcher c-Universidad Politécnica Salesiana Cuenca, Ecuador
{jviola, jrestrepoz, fquizhpi}@ups.edu.ec
b-Universidad Simón Bolívar Caracas, Venezuela

Abstract:

A predictive control scheme to control the phase currents of a three-phase power converter coupled to the electric grid by means of an LCL network is developed. This kind of coupling offers several advantages when compared to pure inductive coupling networks, namely a greater attenuation of switching harmonics and a smaller size. Equations that model the behavior of the current through the LCL network in terms of the applied voltages are, however, more complicated to obtain. In this paper the difference equations required to implement a discrete predictive control scheme are obtained and tested by simulations when it is operated as an inverter and as a controlled rectifier.


Predictive Control Strategy for DFIG Wind Turbines with Maximum Power Point Tracking Using Multilevel Converters

José Sayritupac, Eduardo Albánez, Johnny Rengifo, José M. Aller and José Restrepo
Universidad Simón Bolívar, Caracas–Venezuela
Email: {ealbanez,jwrengifo}@usb.ve
PROMETEO-SENESCYT, Ecuador Universidad Politécnica Salesiana, Cuenca Ecuador
Email: jaller@ups.edu.ec

Abstract:

This paper proposes a control scheme for a wind turbine using a DFIG electromechanical converter, implemented through an NPC three-level back to back converter, that keeps a unitary power factor injection to the grid and maximizes the energy harvested from wind, using a maximum power point tracking algorithm (MPPT). A predictive direct power control (DPC) strategy drives the grid-side converter, to maintain the DC bus reference voltage. Whereas, a predictive direct torque control (DTC) strategy drives the machine-rotor-side converter, to control the power extraction, the power factor and balancing of the DC bus capacitors. The developed model allows to study the wind energy conversion system (WECS) for energy harvesting, rotor dynamics and power quality analysis. Simulation results endorse the effectiveness of the advanced control techniques for the whole wind spectrum, including the pitch angle control. A sensitivity analysis shows that the predictive DTC control strategy is robust with an uncertainty up to 20% of the induction machine parameters.


Proposal and Requirements for a Real-Time Hybrid Simulator of the Distribution Network

D. X. Morales, Member IEEE, R. D. Medina, Member IEEE and Y. Besanger, Senior Member, IEEE

Abstract:

Liberalized markets and strong integration of distributed generation changes significantly the operation and control of distribution grids. Traditional network must be able to integrate new services such as electric vehicles, distributed generation, new loads as inductions cookers without major problems. These new grids should manage those new services intelligently, keeping power quality, safety margins and optimal costs. In order to probe the integration of new loads/services, it is necessary to simulate and analyze distribution system with those new characteristics, stability and different topologies. This paper presents a methodology to design a real time hybrid PHIL simulation using Matlab-Simulink® environment. Additionally, the authors suggest a methodology for integrating real information in the design.


Switched Reluctance Machine Fuzzy Modeling Applied on a MRAC Scheme

Arnaldo Matute, Julio Violab; José Restrepoa, José Manuel Allera, Flavio Quizhpic
Universidad Simón Bolívar Caracas, Venezuela
arnaldo.matute@gmail.com
Prometeo Project Researcher, Universidad Politécnica Salesiana Cuenca, Ecuador

Abstract:

This paper proposes an approach for modeling a Switched Reluctance Machine with fuzzy logic. The proposed model is verified under a Model Reference Adaptive Control scheme. Calculating Fuzzy Inference Systems instead of the nonlinear terms of state equations decreases the model complexity and computing costs, which is important for the MRAC scheme, and provides  mathematical model for adaptive control. Amodel architecture is presented where linear equations interact with a Fuzzy Inference System. An angular speed control experiment was successfully simulated using the resulting fuzzy model as reference.


Two-Phase Active Power Filter Direct Current Control with Capacitor Voltages Estimation and Balance

Marco Fajardoa, Julio Viola-a,b, José Restrepo-b,c, Flavio Quizhpia, José Allera,-b,c
a-Universidad Politécnica Salesiana b-Prometeo Project Researcher Cuenca, Ecuador
mfajardom@ups.edu.ec,{jcviola, restrepo}@ieee.org,fquizhpi@ups.edu.ec
c-Universidad Simón Bolívar Caracas, Venezuela
jaller@usb.ve

Abstract:

In this paper an active power filter is presented based on a multilevel converter. The active power filter is intended to be used in domestic applications where reactive power compensation in two-phase networks is required. An innovative technique to balance the DC bus voltages of the power converter capacitors is proposed and also an estimation algorithm for those voltages is developed, allowing for an operation of the power filter with reduced sensors number.


2014


A Flexible Hardware Platform for Applications in Power Electronics Research and
Education

Julio Viola-a,c, José Restrepo-a,b,c, Flavio Quizhpi-c, María I. Giménez-b, José Aller-b, Víctor Guzmánb, Alexander Bueno-b
a-Prometeo Project Researcher
c-Universidad Politécnica Salesiana Cuenca, Ecuador
{jviola, jrestrepoz, fquizhpi}@ups.edu.ec
b-Universidad Simón Bolívar Caracas, Venezuela
{mgimenez, jaller, vguzman, abueno}@usb.ve

Abstract:

This work presents the design and development of a three-phase multilevel hardware platform for applications in power electronics. The emphasis of the proposed converter is in its flexibility to allow rapid set ups of different experiments typically required in power electronics teaching and research. The proposed converter uses a cascaded H-bridge topology whereby multilevel operation with up to 9 voltage levels can be obtained. The selected power stage topology as well as the control, drivers and sensors boards designs, enable the platform to operate in multiple configurations, namely as inverter, controlled rectifier or active power filter, for one, two or three-phase systems.


DC Voltage Estimation Methods for Multilevel Converter Operating with Reduced Number of Sensors

Julio Viola, Erick Baethge, Alberto Berzoy, José Restrepo
Universidad Simón Bolívar – Caracas, Venezuela
Email: jcviola@usb.ve

Flavio Quizhpi
Universidad Politécnica Salesiana – Cuenca, Ecuador
Email: fquizhpi@ups.edu.ec

Abstract:

Two methods for the estimation of the DC voltages in the capacitors associated to the DC buses in a cascaded multilevel converter topology are analyzed. To reduce the number of voltage sensors, available information from inductor currents and line voltage sensors is used as input to a discrete time model of the converter. Additionally, information from the switching state of each converter’s cell is used allowing an estimation of voltages in each capacitor. Both methods are developed, implemented and simulated for a 9 level three-phase cascaded multilevel converter when it is operated as a controlled rectifier at unity power factor. The analyzed methods have low computational cost allowing its implementation in real time.


Diseño e Implementación del Sistema de Control de un Inversor Multinivel de Fuentes Independientes, por medio de Modulación Vectorial Espacial

J. Galarza F. Quizhpi
Universidad Politécnica Salesiana

Abstract:

El presente trabajo muestra los pasos seguidos, para la implementación del sistema de control de un inversor multinivel. El estudio parte de la topología de fuentes independientes utilizada, luego se describe la implementación del algoritmo de consideraciones geométricas usado y los sistemas de monitoreo y protección en una placa basada en FPGA. Por último se presentan los resultados de la puesta en funcionamiento del sistema completo, con las mediciones de la tensión y la frecuencia obtenidas a la salida del inversor, y el THD en la corriente y tensión en la carga, el cual fue alrededor del 7% con una carga resistiva, e inferior al 3% en un motor asíncrono


Fast detection of sequence components using Savitzky-Golay filters

José Restrepo-a,b,c, Julio Viola-a,b, Flavio Quizhpi-b
a-Prometeo-SENESCYT, Quito-Ecuador
b-Universidad Politécnica Salesiana, Cuenca-Ecuador
c-Universidad Simón Bolívar, Caracas-Venezuela
email:restrepo@ieee.org,{jviola, fquizhpi}@ups.edu.ec

Antonio Ginart
SolarMax USA, Inc. Norcross, GA 30093, USA
email: Antonio.Ginart@solarmax.com

Abstract:

This paper proposes a new positive and negative sequence detector for fast system’s protection. The proposed detector scheme uses Savitzky-Golay filters, to get a filtered version of the signals’ time derivatives. A comparison, using simulations and experimental tests, of the proposed detector and of a second order generalized integrator (SOGI) based detector, shows the advantages of the former.


Fault detection and correction on real time of a twostage three-phase multilevel inverter of controlled by vector modulation

Alexis Llanosa, Christian Saavedraa,Flavio Quizhpia
a Universidad Politécnica Salesiana
Cuenca, Ecuador (ECO10105)
Email:{allanos,csaavedra}@est.ups.edu.ec,fquizhpi@ups.edu.ec
Research group of renewable energy (CIDII)

Abstract:

A method for correcting faults in real time on the IGBTs of a multi-level system of two stages, by varying the states on vector modulation is presented. Also in addition the results obtained by implementing this method, keeping a signal voltage constant, ensuring continuous operation, is also given.


Genetic Algorithm for Enhancing the Transmission Capacity of a PES (Power Electric System) through Flexible AC Compensators

Fabián Arévalo, Martin Cordova, Flavio Quizhpi, Magno Vivar
Department of Electric Engineering, Universidad Politécnica Salesiana, Cuenca, Ecuador
farevalo@est.ups.edu.ec, mcordovas@est.ups.edu.ec, fquizhpi@ups.edu.ec,mvivar@ups.edu.ec

Abstract:

This document presents the implementation of a Genetic Algorithm (GA) in Matlab software as it is complemented in Guide in order to visualize the GA through a graphic interface, which uses Flexible AC Transmission Systems (FACTS) aimed to enhance the transmission capacity of an Electric Power System, emulating the process of a living organism which afterwards will be evolutionary in order to find better solutions on the dilemma of optimization.


Initial Results from a Prototype Corresponding to an Induction Water Heater

Luis F. Quevedoª, Flavio A. Quizhpiª, John A. Moralesª, Roberto J. Cabralb and Arturo S. Bretasb
Email: lquevedo@est.ups.edu.ec, fquizhpi@ups.edu.ec, jmoralesg@ups.edu.ec, rjcabral@ece.ufrgs.br,
abretas@ece.ufrgs.br
ªCarrera de Ingeniería Eléctrica Universidad Politécnica Salesiana, Cuenca, Ecuador.
bFederal University of Rio Grande do Sul, Porto Alegre, Brasil.

Abstract:

It is clear that the development of new methodologies that increase the electrical systems efficiency and the welfare of users, avoiding pollution as best as possible, are highly desired by researchers and utilities. In this context, in Ecuador, basic service elements like water heaters are usually used by population. Where, currently water heaters based on Liquefied Petroleum Gas (LPG) are used. However, these devices are harmful for the country’s economy. In this research, a novel prototype corresponding to an induction water heater is proposed. This has three operation stages corresponding to rectification, filtering, and controlling single-phase inverter by sinusoidal pulse width modulation (SPWM). In order to validate the proposed work, different test at each operation state, were developed. Results show an acceptable performance. Therefore, the prototype can be considered as an alternative to traditional devices.


Shunt active power filter for harmonic compensation of two-phase nonlinear loads

Héctor Buenoa, Marco Fajardoa, Flavio Quizhpia, Julio Violaa;c, José Restrepoa;b;c
a-Universidad Politecnica Salesiana Cuenca, Ecuador (EC010105)
Email: {hbueno}@est.ups.edu.ec,{mfajardom,fquizhpi,jviola,jrestrepoz}@ups.edu.ec
b-Universidad Simón Bolívar Caracas, Venezuela (1080A)
c- Prometeo Project Researcher (SENESCYT)

Abstract:

A new topology for a two-phase shunt active power filter using a voltage source converter is proposed. The converter is controlled with a predictive control algorithm based in a discrete mathematical model of the system which allows to minimize the quadratic error between the lines currents and the reference currents. The whole system is tested with simulations and with a prototype experimental setup, showing its effectiveness in the compensation of current harmonics produced by two-phase nonlinear loads.


Simplified FPGA implementation of the generalized space vector pulse width modulation (GSVPWM) for three wire three-phase inverters

Jose Restrepo-a,b,c, Julio Viola-a,b, Flavio Quizhpi-b
a-Prometeo-SENESCYT, Quito-Ecuador
b-Universidad Politécnica Salesiana, Cuenca-Ecuador
c-Universidad Simón Bolívar, Caracas-Venezuela
email:restrepo@ieee.org,{jviola, fquizhpi}@ups.edu.ec

Abstract:

This paper presents the development and implementation on a low-cost FPGA, of a fast generalized space vector pulse width modulation (GSVPWM) scheme. The implemented pulse width modulation uses a standard carrier-based triangle interception method (SPWM).


Sistema de identificación para filtros activos de potencia

Felipe Peña1, Julio Viola1,2, José Restrepo1,2,3
1 Grupo de Investigación en Energía-Universidad Politécnica Salesiana, Cuenca, Ecuador.
2 Proyecto Prometeo – SENESCYT, Ecuador.
3 Universidad Simón Bolívar, Caracas, Venezuela.

Abstract:

El presente artículo es un estudio de un sistema de identificación, aplicado a filtros activos de potencia, utilizando convertidores multinivel. El sistema de identificación, fue implementado mediante simulación, utilizando el método por mínimos cuadrados. La aplicación del algoritmo de identificación, permitió obtener los coeficientes del modelo del circuito de interconexión entre la red de distribución y el convertidor, para representarlo en ecuación de diferencias. El modelo identificado, servirá para diseñar diferentes tipos de controladores digitales para implementar en convertidores, con el objetivo de disminuir la distorsión armónica total de la red, y la corrección del factor de potencia. El estudio incluye un análisis comparativo de la identificación del filtro activo con carga no lineal y un filtro tipo LCL, representado como modelo lineal.


2013


Analysis of a Four-Phase Induction Machine with Direct Torque Control

Julio Viola†‡, Flavio Quizhpi‡, Jose Restrepo†, Juan Pablo Pesntez‡, Marco Miguel Sanchez‡
†UNIVERSIDAD SIMON BOLIVAR, ‡UNIVERSIDAD POLITECNICA SALESIANA
†Valle de Sartenejas, Baruta, Edo. Miranda, Caracas, Venezuela
‡Calle Vieja y Elia Liut, Cuenca, Azuay, Ecuador
Phone: +58 (212) 906-4012
Email: jcviola@usb.ve
URL: http://www.usb.ve

Abstract:

In this work the design and control of a four-phase induction machine (4P-IM) is addressed. The 4PIM is controlled using a four-phase voltage source inverter (4P-VSI) with a generalization of the classic direct torque control (DTC) scheme. An analysis of the available valid switching states and voltage space vectors is developed and a switching table is obtained. Finally, the system’s fault tolerant characteristics are briefly considered for operation with gate suppression in one IGBT. In this case, operation is still possible with the use of switching strategy that employs the remaining space vectors available during the fault.


Desarrollo de algoritmo para la protección diferencial del transformador de potencia aplicado a la subestación.

Guillen Freddy, Narveaz Javier, Quizhipi Flavio

Departamento de Electrica de la Universidad Politécnica Salesiana Sede Cuenca

Abstract:

Este trabajo condensa los resultados obtenidos  en el desarrollo, simulación y comparación del algoritmo de  protección diferencial, que basa su funcionamiento en el  bloqueo de armónicos, empleando la transformada discreta  de Fourier; capaz de proteger al transformador de potencia  de fallas internas, bloqueando la desconexión ante la  presencia de estados de no falla como Energización y Sobre - excitación.

 



Desarrollo de un Convertidor Electrónico Multinivel para Aplicaciones
de Compensación de Potencia Reactiva

J.C. Viola † F. Quizhpi ‡
† Dpto. Electrónica y Circuitos, Universidad Simón Bolívar, Caracas, Venezuela. Investigador
‡ Proyecto Prometeo, Universidad Politécnica Salesiana, Cuenca, Ecuador.

Abstract:

El trabajo presenta el proceso completo de diseño y construcción de un convertidor electrónico de potencia de 9 niveles en configuración cascada destinado para su uso  como compensador estático de potencia reactiva en instalaciones industriales trifásicas. El trabajo abarca el dimensionamiento y montaje de la etapa de potencia compuesta por 24 módulos de transistores bipolares de compuerta aislada (IGBTs) de 150A y 1 200V cada uno y por 3 disipadores de aluminio, como así también todo el diseño y desarrollo de las tarjetas de adquisición, disparo y control necesarias para manejar el convertidor a lazo cerrado. Las tarjetas de adquisición se diseñaron utilizando sensores de efecto Hall para tensión y corriente y transmisión  de datos para tensión y corriente y  transmisión de dato por fibra óptica para asegura aislaciòn  entre la tarjeta de control y la etapa de potencia. Para el control del convertidor de diseñó una tarjeta basada en un arreglo de lógica programable (FPGA) interconectada con un procesador digital de señales (DSP) que permite la alta velocidad de procesamiento requerida para probar distintas técnicas de control. El convertidor es controlado por modulación de ancho de pulso (PWM) conmutando a una frecuencia de 10kHz y pudiendo ser conectado a tensiones de hasta 3kV.


Desarrollo de un Modelo Biestratificado de Terreno Aplicando un Software Computacional en el Sector Industrial

Ángel T. Pacheco G. Jonathan M. Jiménez Z.
apachecog@est.ups.edu.ec jimenezj_ups@hotmail.com
Flavio A. Quizhpi P.
fquizhpi@ups.edu.ec
UNIVERSIDAD POLITÉCNICA SALESIANA
Carrera de Ingeniería Eléctrica

Abstract:

El artículo presenta el desarrollo de una metodología para modelos biestratificados de terrenos para ser aplicados a futuro en el estudio y análisis de mallas de Sistemas de Puesta a Tierra (SPT) aplicados a los sectores industriales. El modelo es desarrollado mediante metodologías genéricas del modelo Tagg de acuerdo a las especificaciones de la norma ANSI/IEEE Std 81-1983, que permite analizar cualquier tipo de suelo de acuerdo a las características comunes de suelo y así establecer las condiciones ideales que podrán ser utilizadas para el cálculo de los potenciales de paso y contacto, mediante las ecuaciones pertinentes.


DISEÑO DE SISTEMAS DE PUESTA A TIERRA PARTIENDO DE UN MODELO BIESTRATIFICADO DE TERRENO, APLICANDO UN SOFTWARE COMPUTACIONAL EN EL SECTOR INDUSTRIAL

Jiménez Z. Jonathan M., Pacheco G. Ángel T., Quizhpi P. Flavio A. Universidad Politécnica Salesiana Carrera De Ingeniería Eléctrica Campus El Vecino

Abstract:

Se aborda un problema típico en la ingeniería eléctrica, el diseño de sistema de puesta a tierra, que tiene una diversidad de criterios. El artículo presenta los aspectos normalizados en la IEEE y las experiencias de los autores para el apropiado diseño del sistema de puesta a tierra aplicado en instalaciones de tipo industrial, se desarrolla una aplicación sobre MatLab para cumplir con el objetivo. Se tomó como referencia una proyección de una modelación de terrenos biestratificados. Se ha validado los resultados comparándolos con diseños que prestan garantías con los índices de seguridad, se han comparado diseños expresados como referentes por algunas empresas eléctricas o industriales y diseños que proporcionan software especializados como el caso del CYMDIST. La propuesta desarrollada entrega datos que garantizan un diseño con todos los parámetros de seguridad para la implementación de los sistemas de puesta a tierra para sistemas industriales.


“Diseño y Construcción de Filtro Activo para Eliminar Armónicos de una Red Bifásica Residencial.”

Héctor Bueno1, Marco Fajardo1, Flavio Quizhpi1*

1 Universidad Politécnica Salesiana, Cuenca, Ecuador

* fquizhpi@ups.edu.ec

Abstract:

El aumento constante de las cargas no lineales conectadas a la red de alimentación, provocan problemas como altos índices de distorsión armónica y pérdida de eficiencia debidos al bajo factor de potencia. Una de las formas de mejorar esta situación, es la utilización de filtros activos de potencia (PAF). Se desarrolla un filtro multinivel para una red bifásica, con la característica principal de inclusión del neutro en el filtrado logrando un equilibrio entre fases y neutro. Obteniendo como resultado que la forma de onda de la corriente que circula por la red eléctrica sea senoidal (bajo factor armónico). Estructuralmente el filtro, en su sistema de potencia, consta de dos puentes inversores o dos etapas por fase, para la carga o descarga de los dispositivos almacenadores de energía, que para el presente caso es de tipo capacitivo, obteniendo así cinco niveles de tensión por fase. En lo que corresponde al sistema de control del filtro está basado en un control predictivo y adaptativo. Se hace la predicción del estado de conmutación  de los IGBT´s de los inversores en base a los cálculos de la función costo de corriente y la comparación con una corriente de referencia que depende de la carga de la red.

 

Una vez implementado el filtro se comprobó el cumplimiento de los objetivos, se demostró que existe una reducción en el THD de corriente, además se dio la corrección  deseada en la forma de onda de la corriente y del voltaje, mejorando así la eficiencia de la red.


Model of the InductionMachine including Saturation

Jose M. Aller , Daniel Delgado, Alexander Bueno, Julio C. Viola and Jose A. Restrepo
UNIVERSIDAD SIMON BOLIVAR
Valle de Sartenejas, Baruta, Edo. Miranda
Caracas, Venezuela
Development Bureau of the Simón Bolívar University (GID-04) and Universidad Politécnica Salesiana -Ecuador

Abstract:

This work proposes a model for induction machines in natural coordinates “abc”, developed considering the nonlinear characteristics of saturation. Traditionally, the models for the induction machine including this effect make use of linear transformations. However, the nonlinearity of saturation does not allow the use of these transformations, giving invalid results. Flux linkage in each phase leads to the saturation coefficient and this to the magnetic permeance. Hence, the saturation coefficient produces a new inductance in natural coordinates that considers the nonlinearity of saturation. The machine behavior is computed using a state variable model in natural coordinates described in the space vector frame. The results obtained by the proposed model give a better harmonic representation than the “dq0”models obtained by neglecting the magnetic hysteresis effect. A comparison between the proposed representation and the traditional one shows the advantages of the former.



Motor de Inducción de una Sola Espira

F.A. Quizhpi F. Bresciani
Universidad Politécnica Salesiana – Cuenca, Ecuador

Abstract:

El trabajo presenta el proceso completo de diseño y construcción de un motor trifásico de una sola espira. El motor es destinado para uso como máquina normal con la ventaja de trabajar a tensión próxima a cero. Se presenta el dimensionamiento y montaje del devanado estatórico sobre núcleo  magnétic. Para verificar  el nivel de rendiminto y su uso eficiente de energia  se realiza el análisis de la respuesta ante el sistema de alimentación nominal, esto es tensión cero, respuestas ante condiciones de funcionamiento en vacío, con carga y cortocircuito de barra. Se verifica que la alimentación de la red contaminada es filtrada con el sistema  de  bobina de sola espira, manteniendo parámetros mecánicos. Se demuestra que el sistema aporta, sobre el sistema contaminado, con reducciones de armónicos conforme cambie las características de la carga máquina.


Vector Analysis of a Four-Phase Induction Machine

Julio Viola
Universidad Simón Bolívar – Caracas, Venezuela
Proyecto Prometeo SENESCYT – Cuenca, Ecuador
Email: jcviola@usb.ve

Flavio Quizhpi, Gustavo Parra
Universidad Politécnica Salesiana
Cuenca, Ecuador
Email: fquizhpi@ups.edu.ec; gustavoparra1104@hotmail.com

Abstract:

In this work a vector analysis for a previously designed four-phase induction machine (4P-IM) is addressed. The set of equations that models the 4P-IM is developed and used to obtain simulations of the machine performance when it is started with a balanced four-phase voltage system which is obtained with a special transformer arrangement. The topology of a four-phase voltage source inverter (4P-VSI) is analyzed prior to be connected to the machine. Simulations and experimental results are obtained when the 4P-IM is started with the 4P-VSI.


2012


Análisis Técnico de una Central Solar para la Producción de Energía Eléctrica en el Cantón Santa Isabel de la Provincia del Azuay

Washington E. Macancela V., Edmundo V. Regalado C., Fredy F. Campoverde A. y Flavio A. Quizhpi P.
Carrera de Ingeniería Eléctrica, Grupo de Energías, CIDII
Universidad Politécnica Salesiana, Ecuador

Abstract:

Se realizó la evaluación de una serie de mediciones de radiación solar tomadas por ElecAustro S.A. durante varios años en la región de Uchucay-Sumaypamba, cercanas al Proyecto Eólico Minas de Huascachaca de la misma Empresa, se considero el análisis técnico, verificando normativa, para determinar un perfil de Irradiación promedio, dato necesario para establecer una posible producción de electricidad y el tipo de central solar que aporte la máxima producción para enlazarla al sistema nacional interconectado. Con la finalidad que una futura Central Solar se implemente, es necesario estudiar las regulaciones del sector aplicadas a energías no convencionales. Para lograr mayor fiabilidad acerca de las alternativas obtenidas, se realizó un Análisis Económico, determinando la opción de mayor rentabilidad versus la inversión por vatio instalado en la central. Finalmente se calculó las emisiones que evitaría se emanen a la atmósfera y los ingresos por la venta de bonos de carbono. ——Palabras clave —Irradiación, Irradiancia, Fotovoltaico (F.V.), Dish Stirling, Colectores Cilindro Parabólicos (CCP), SNI,
Central Solar.


Detección de Fallas en el Aislamiento en las Chapas del Estator de Máquinas Eléctricas Rotativas

Luisa Salazar 1,∗, Flavio Quizhpi 2, José Manuel Aller 3, Alexander Bueno 4, Rodney Reyna 5

Abstract:

En este trabajo se comparan dos metodologías para la detección de cortocircuitos y fallas entre chapas de núcleos magnéticos, para lo cual se realizaron los ensayos sobre las chapas que conforman el estator de un motor de inducción, con el objetivo de determinar el método de detección más eficaz. Los métodos sometidos a comparación son: Método de la prueba de aislamiento del laminado del núcleo del estator, recomendado por el estándar IEEE-56 Guide for Insulation Maintenance of Large Alternating - Current Rotating Machinery (10000 KVA and Larger) y el método de variaciones de flujo, el cual permite mediante dos electroimanes o bobinas (sensora y patrón) sobre las chapas, determinar las variaciones en magnitud y fase de la corriente que circula por las mismas, ubicando los puntos de falla.


Diagnóstico y Evaluación de la Confiabilidad del Alimentador  122 para la Empresa Eléctrica Azogues C.A. usando el Método de Simulación de Montecarlo

M. Escudero J. Rojas F.Quizhpi
Universidad Politécnica Salesiana Cuenca

Abstract:

El presente trabajo es un estudio para el análisis y evaluación de confiabilidad del  Alimentador # 122 para la Empresa Eléctrica Azogues, aplicando Montecarlo. En primer lugar, se hace el cálculo estadístico de los índices que modelan el comportamiento del sistema de distribución 22/12,7kV par  posteriormente, conocer las zonas críticas del alimentador así como los puntos de mayor impacto conforme la indisponibilidad de los componentes.

 


EVALUACIÓN DEL COMPORTAMIENTO DE UN SISTEMA ELECTRICO AISLADO ANTE RAMPAS DE VIENTO UTILIZANDO AEROGENERADORES DE VELOCIDAD FIJA

L.J. Salazar† F.A.Quizhpi‡
† Departamento de Tecnología Industrial, Universidad Simón Bolívar, Caracas, Venezuela
Email: luisalazar@usb.ve
‡ Departamento de Ingeniería Eléctrica y Electrónica, Universidad Politécnica Salesiana, Cuenca, Ecuador
Email: fquizhpi@ups.edu.ec

Abstract:

Las turbinas eólicas producen fluctuaciones de potencia continuas y complejas, que se deben principalmente a la variación de la velocidad del viento. Estas variaciones afectan la calidad de energía y fluctuaciones; y por tal motivo es importante la simulación precisa de las fluctuaciones de potencia de las centrales eólicas durante su operación continua. Con el objetivo de investigar las características operativas de un sistema de conversión de energía eólica, es deseable y conveniente disponer de un registro secuencial, por un año al menos, de velocidades de viento. Algunas veces no está disponible esta información para el análisis de los datos reales. Tener medidas del viento tiene como ventaja que al utilizarse en los modelos dinámicos se determina con mayor precisión el desempeño de la turbina. En este trabajo teniendo como base los resultados de estabilidad transitoria para las diferentes fallas monofásicas y trifásicas en el sistema eléctrico en estudio, se realizan simulaciones y análisis del comportamiento del sistema para el caso de un parque eólico de 20 MW con aerogeneradores de velocidad fija para rampas de viento que inician y finalizan desde velocidad mínima – velocidad máxima y velocidad máxima – velocidad mínima.


Mantenimiento Centrado en la Confiabilidad (MCC) Aplicado a los equipos de Recepción, Esterilización, Envasadoras para la elaboración de la leche UHT, empleando modelo matemático de las cadenas de Markov

Freddy Yerovi, Marcos Peralta y Flavio Quizhpi
Carrera de Ingeniería Eléctrica, Grupo de Energías, CIDII
Universidad Politécnica Salesiana, Ecuador

Abstract:

El mantenimiento de los equipos de proceso de elaboración de Leche UHT, representa un reto
importante debido a las condiciones existentes en las plantas procesadoras. Además, los equipos
de proceso para producción involucrados son críticos. El mantenimiento juega un papel
determinante para mantener o incrementar los niveles de disponibilidad, por esta razón debe
ser evaluado y corregido con herramientas objetivas. En este trabajo se utilizan modelos basados
en cadenas de Markov e indicadores probabilísticos que permiten analizar y corregir los
procesos de chequeo, mantenimiento preventivo y correctivo utilizado en la planta. Los datos
obtenidos a partir de las reuniones del Grupo Mantenimiento Centrado en Confiabilidad (MCC)
y las conclusiones que se obtuvieron de la planta, se han utilizado como insumo para analizar
sus procesos de mantenimiento, evaluar alternativas y proponer cambios que incrementen la
disponibilidad de la planta. Con la ayuda del MCC aplicando el modelo matemático de Markov
se obtuvieron resultados aceptables a lo largo de los seis meses que se realizó el análisis
y la elaboración del sistema a implementar. Se elaboraron una serie de listas para chequeo que
fueron implementadas con MCC y se cumplieron de acuerdo al tiempo que se establece como
recomendable. Debido a la naturaleza estocástica inherente a los componentes del sistema se
muestra el uso del Mantenimiento Centrado en la Confiabilidad para su elaboración con el uso
de las Cadenas de Markov para la forma de implementación y como decidir sobre registros a
seguir después de los resultados obtenidos. Finalmente se presenta un análisis de las ventajas
económicas que conlleva la implementación del sistema. ——Palabras clave —Confiabilidad,
Cadenas, Leche, Mantenimiento, Markov, Pasteurización, Proceso, Ultrapasteurización.


 

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