A novel voltage sag approach during unintentional islanding scenarios: A survey from real recorded events

In this paper, a new voltage sag approach is analytically modelled and validated using both simulation and field measurements. The main aspect of this approach is to propose a new voltage sag feature which appears during unintentional islanding operations (IOs). The unintentional IO occurs when an induction motor is removed from the main utility following a circuit breaker (CB) clearing, transiently, the induction motors (IMs) are acting as generators maintaining the affected distribution feeder with voltage until it is reconnected. The voltage sag modelled in the current article follows an exponential form, as a matter of fact, here it will be demonstrated that the proposed model reaches satisfactorily the field measurements and evidences the dependability of the model adopted. Furthermore, it is worthwhile to note that this novel power quality (PQ) event has not been investigated yet and enhances voltage sag studies. Lastly, it is crucial to point out that all recorded events and a large amount of data needed so as to validate this transient, has been measured in a distribution network (DN) located in Spain.Postprint (published version

A novel voltage sag approach during unintentional islanding scenarios: A survey from real recorded events

In this paper, a new voltage sag approach is analytically modelled and validated using both simulation and field measurements. The main aspect of this approach is to propose a new voltage sag feature which appears during unintentional islanding operations (IOs). The unintentional IO occurs when an induction motor is removed from the main utility following a circuit breaker (CB) clearing, transiently, the induction motors (IMs) are acting as generators maintaining the affected distribution feeder with voltage until it is reconnected. The voltage sag modelled in the current article follows an exponential form, as a matter of fact, here it will be demonstrated that the proposed model reaches satisfactorily the field measurements and evidences the dependability of the model adopted. Furthermore, it is worthwhile to note that this novel power quality (PQ) event has not been investigated yet and enhances voltage sag studies. Lastly, it is crucial to point out that all recorded events and a large amount of data needed so as to validate this transient, has been measured in a distribution network (DN) located in Spain.Postprint (published version

Power quality disturbances assessment during unintentional islanding scenarios. A contribution to voltage sag studies

This paper presents a novel voltage sag topology that occurs during an unintentional islanding operation (IO) within a distribution network (DN) due to large induction motors (IMs). When a fault occurs, following the circuit breaker (CB) fault clearing, transiently, the IMs act as generators due to their remanent kinetic energy until the CB reclosing takes place. This paper primarily contributes to voltage sag characterization. Therefore, this novel topology is presented, analytically modelled and further validated. It is worth mentioning that this voltage sag has been identified in a real DN in which events have been recorded for two years. The model validation of the proposed voltage sag is done via digital simulations with a model of the real DN implemented in Matlab considering a wide range of scenarios. Both simulations and field measurements confirm the voltage sag analytical expression presented in this paper as well as exhibiting the high accuracy achieved in the three-phase model adopted.Postprint (published version

Theorical and descriptive analysis of the wave energy in the Barcelona World Race

The main objective of this paper is the presentation of a theoretical study of the wave energy in some zones of the Barcelona World Race (BWR) considering different theories, how much of this energy is transferred to the boat and if it is possible to use that energy, as propulsion energy. Nowadays, the absorption of wave energy (offshore, inshore or on board) is low utilized and has important costs. That makes this subject become more interesting. The first section of this paper is a study of the movement of the waves with different descriptions and of the energy potential depending on characteristic’s value. Secondly, a categorization of the wave’s characteristics is done of a part of BWR with the objective to be able to do an energy atlas of different areas. After that, a model of the vertical motion (simplified motion) is done in order to express the energy which is in the kinetic phase difference between the wave action and the boat reaction. Finally, all factors in the synchronism motion between wave and boat have been evaluated (in surf navigation) in order to analyze the results of equilibrium and the result force with different power propulsion.Postprint (published version

Assessment of unintentional islanding operations in distribution networks with large induction motors

This paper is aimed at assessing the impact of unintentional islanding operations (IOs) in the presence of large induction motors (IMs) within distribution networks (DNs). When a fault occurs,followingthecircuitbreaker(CB)faultclearing,theIMsacttransientlyasgenerators,duetoits inertia, until the CB reclosing takes place. The present work is the outcome of a project carried out in a small DN, where ¿eld measurements were recorded over two years. This paper provides a detailed description of the test system, a selected list of ¿eld measurements, and a discussion on modeling guidelinesusedtocreatethemodeloftheactualpowersystem. Themaingoalistovalidatethesystem model by comparing ¿eld measurements with simulation results. The comparison of simulations and ¿eld measurements prove the appropriateness of the modeling guidelines used in this work and highlight the high accuracy achieved in the implemented three-phase Matlab/Simulink modelPostprint (published version

Realization of a 10 kW MES power to methane plant based on unified AC/DC converter

This paper presents a galvanic isolated multi output AC/DC topology that is suitable for Microbial electrosynthesis (MES) based Power to Methane energy storage systems. The presented scheme utilizes a three phase back to back converters, a single-input and multiple-output three phase transformer, single diode rectifiers and buck converters that employ a proper interconnection between MES cells and the mains. The proposed topology merges all the required single phase AC/DC converters as a unified converter which reduces the overall system size and provides system integrity and overall controllability. The proposed control scheme allows to achieve the following desired goals:1) Simultaneous control of all cells; 2) Absorbing power from the grid and covert to methane when the electricity price goes down; 3) the power factor and the quality of grid current is under control; 4) Supplying MES cells at the optimal operating point. For verification of system performance, Real time simulation results that are obtained from a 10-kW MES energy storage are presented.Postprint (author's final draft

The influence of the self-excited induction machine into the electrical grid under instability situation - Real case measurement

The three phase induction machine is used in the mainly part of the industry and it requires reactive power from the grid to start and function. The reactive power consumption is economically fined so the industries install capacitors in parallel with the motors and loads. The bank capacitor, gives this reactive power to the machine in order to improve the cos f factor in the installation. When a fault appears in the grid, this machine gives the active power to the fault, but when the overcurrent relay sets the fault, the induction machine is already with inertia with electromagnetic and mechanic specific parameters that originate a non-controlled islanding mode and it provides the power to the loads on this feeder. Even though several works are published within the islanding detection, the islanding operation about the induction machine as a generator in power wind energy applications, nevertheless in the following we show the motor perspective. The stability of the system in the time period between the relay opening and the fast reconnection is out of control, so a complete study a about the electric magnitudes, voltage and reactive power , active power and frequency and the angle stability is needed. In this paper we show a real case that appears in a distribution Medium Voltage (MV) radial network in Spain in a 25 kV feeder and we summarize the voltage /current wave form and the frequency oscillation.Postprint (published version

Detection of partial discharges in an underground electrical installation by means of digital thermal image processing

The installation of power cables must be considered a series of factors to ensure good performance in its operation and thus significantly improve the reliability of the system where it is located. During the installation, the use of specific accessories for connection to aerial systems or for connection of equipment is involved, such accessories are known as terminals and splices. According to the statistics, these accessories present 90% of the failures due to problems during their installation or its life, so it is necessary to carry out scheduled studies or monitoring of the operation of electrical installations in order to reduce risks and prevent installation failures. In the present work, an incipient fault detection method is presented, which is based on the analysis of thermographic images of the accessories (splices and terminals) of medium voltage in operation. The objective is to identify the area of a terminal in which there is an incipient failure due to partial discharges, which cannot be observed with a simple thermographic image, but rather requires a digital analysis and processing of the thermographic image in order to identify the point of failure where with digital image processing it is possible to extract information that is not perceived by the naked eye in an image obtained with a thermal imaging camera. The results obtained in the laboratory of faults previously established in an underground electrical installation model are presented.Peer ReviewedPostprint (published version

Developing BP-driven web application through the use of MDE techniques

Model driven engineering (MDE) is a suitable approach for performing the construction of software systems (in particular in the Web application domain). There are different types of Web applications depending on their purpose (i.e., document-centric, interactive, transactional, workflow/business process-based, collaborative, etc). This work focusses on business process-based Web applications in order to be able to understand business processes in a broad sense, from the lightweight business processes already addressed by existing proposals to long-running asynchronous processes. This work presents a MDE method for the construction of systems of this type. The method has been designed in two steps following the MDE principles. In the first step, the system is represented by means of models in a technology-independent manner. These models capture the different aspects of Web-based systems (these aspects refer to behaviour, structure, navigation, and presentation issues). In the second step, the model transformations (both model-to- model and model-to-text) are applied in order to obtain the final system in terms of a specific technology. In addition, a set ofEclipse-based tools has been developed to provide automation in the application of the proposed method in order to validate the proposal.Torres Bosch, MV.; Giner Blasco, P.; Pelechano Ferragud, V. (2012). Developing BP-driven web application through the use of MDE techniques. Software and Systems Modeling. 11(4):609-631. doi:10.1007/s10270-010-0177-5S609631114Andrews, T., Curbera, F., Dholakia, H., Goland, Y., Klein, J., Leymann, F., Liu, K., Roller, D., Smith, D., Thatte, S., Trickovic, I., Weerawarana, S.: Business process execution language for Web services version 1.1 (May 2003)Barna, P., Frasincar, F., Houben, G.J.: A workow-driven design of Web information systems. In: Wolber, D., Calder, N., Brooks, C., Ginige, A. (eds.) ICWE, ACM, pp. 321–328Bakshi, K., Karger, D.R.: Semantic Web applications. In: Proceedings of the ISWC 2005 Workshop on End User Semantic Web Interaction (November 2005)Brambilla M., Ceri S., Fraternali P., Manolescu I.: Process modeling in Web applications. ACM Trans. Softw. Eng. Methodol. 15(4), 360–409 (2006)Brambilla, M., Preciado, J.C., Trigueros, M.L., Sánchez-Figueroa F.: Business process-based conceptual design of rich internet applications. In: ICWE, pp. 155–161 (2008)Brambilla, M., Butti, S., Fraternali, P.: Webratio bpm: a tool for designing and deploying business processes on the Web. In: ICWE, pp. 415–429 (2010)Business process modeling notation (BPMN). OMG final adopted specification. dtc/06-02-01 (February 2006)Ceri, S., Fraternali, P., Bongio, A.: Web modeling language (Webml): a modeling language for designing Web sites. In: Proceedings of the 9th international World Wide Web conference on Computer networks : the international journal of computer and telecommunications networking, Amsterdam, The Netherlands, pp. 137–157. North-Holland Publishing Co., The Netherlands (2000)Davis J.: Open Source SOA. Manning Publications Co, Greenwich (2009)Distante, D.: Reengineering legacy applications and Web transactions: an extended version of the UWA transaction design model. Ph.D. thesis, University of Lecce, Italy (2004)Distante D., Rossi G., Canfora G., Tilley S.R.: A comprehensive design model for integrating business processes in Web applications. Int. J. Web Eng. Technol. 3(1), 43–72 (2007)Duhl, J.: Rich internet applications. Technical report, IDC (November 2003)Fons, J.: OOWS: A model driven method for the development of web applications. Ph.D. thesis, Universidad Politécnica de Valencia (2008)Fons, J., Pelechano, V., Pastor, O., Valderas, P., Torres, V.: Applying the OOWS model-driven approach for developing web applications. The internet movie database case study. In: Web Engineering: Modelling and Implementing Web Applications. Human–Computer Interaction Series, pp. 65–108. Springer, London (2008)Fowler, M.: Inversion of control containers and the dependency injection pattern. http://martinfowler.com/articles/injection.html (January 2004)Gershenfeld N., Krikorian R., Cohen D.: The internet of things. Sci Am 291(4), 76–81 (2004)Giner P., Cetina C., Fons J., Pelechano V.: Developing mobile business processes for the internet of things. IEEE Pervasive Comput. 9, 18–26 (2010)Gómez J., Cachero C., Pastor O.: Extending a conceptual modelling approach to Web application design. In: Wangler, B., Bergman, L. (eds) CAiSE. Lecture Notes in Computer Science, vol. 1789, pp. 79–93. Springer, London (2000)Goth G.: The task-based interface: not your father’s desktop. IEEE Software 26(6), 88–91 (2009)Holmes, T., Tran, H., Zdun, U., Dustdar, S.: Modeling human aspects of business processes—a view-based, model-driven approach. In: ECMDA-FA, pp. 246–261 (2008)Kappel, G., Pröll, B., Reich, S., Retschitzegger, W. (eds): Web Engineering—The Discipline of Systematic Development of Web Applications. Wiley, England (2006)Koch, N.: Software Engineering for Adaptive Hypermedia Systems: Reference Model, Modeling Techniques and Development Process. Ph.D. thesis, Ludwig-Maximilians-University Munich, Germany (2001)Koch N., Kraus A., Cachero C., Meliá S.: Integration of business processes in Web application models. J. Web Eng. 3(1), 22–49 (2004)Limbourg, Q., Vanderdonckt, J.: Usixml: a user interface description language supporting multiple levels of independence. In: ICWE Workshops, pp. 325–338 (2004)Linaje M., Preciado J.C., Sánchez-Figueroa F.: Engineering rich internet application user interfaces over legacy Web models. IEEE Internet Comput. 11(6), 53–59 (2007)Link, S., Hoyer, P., Schuster, T., Abeck, S.: Model-driven development of human tasks for workflows. In: ICSEA ‘08: Proceedings of the 2008 third international conference on software engineering advances, Washington, DC, USA, pp. 329–335. IEEE Computer Society, Washington, DC (2008)Marcos, E., Cáceres, P., Castro, V. D.: An approach for navigation model construction from the use cases model. In: CAiSE Forum. Held in conjunction with the 16th Conference On Advanced Information Systems Engineering (June 2004)Pietschmann, S., Voigt, M., Meissner, K.: Adaptive rich user interfaces for human interaction in business processes. In: Proceedings of the 10th International Conference on Web Information Systems Engineering (WISE 2009), WISE, pp. 351–364. Springer LNCS (October 2009)Schwabe D., Rossi G.: An object oriented approach to Web-based applications design. Theor. Pract. Object Syst. 4(4), 207–225 (1998)Schmid H.A., Rossi G.: Modeling and designing processes in e-commerce applications. IEEE Internet Comput. 8(1), 19–27 (2004)Schwinger W., Retschitzegger W., Schauerhuber A., Kappel G., Wimmer M., Pröll B., Cachero C., Casteleyn S., Troyer O.D., Fraternali P., Garrigós I., Garzotto F., Ginige A., Houben G.J., Koch N., Moreno N., Pastor O., Paolini P., Pelechano V., Rossi G., Schwabe D., Tisi M., Vallecillo A., van der Sluijs K., Zhang G.: A survey on Web modeling approaches for ubiquitous Web applications. IJWIS 4(3), 234–305 (2008)Sousa K.S., Mendona H., Vanderdonckt J.: A model-driven approach to align business processes with user interfaces. J. UCS 14(19), 3236–3249 (2008)Sukaviriya, N., Sinha, V., Ramachandra, T., Mani, S.: Model-driven approach for managing human interface design life cycle. In: MoDELS, pp. 226–240 (2007)Tedre M.: What should be automated?. Interactions 15(5), 47–49 (2008)Torres, V., Giner, P., Bonet, B., Pelechano, V.: Adapting BPMN to Public Administration. In: Proceedings BPMN 2010 Springer’s Lecture Notes in Business Information Processing (LNBIP). Postdam, Germany (to appear)Troyer, O.D., Casteleyn, S.: Modeling complex processes for Web applications using wsdm. In: Proceedings of the Third International Workshop on Web-Oriented Software Technologies (held in conjunction with ICWE2003), IWWOST2003 (2003