Springer Theses Recognizing Outstanding Ph.D Research Hugo Campelo FluSHELL – A Tool for Thermal Modelling and Simulation of Windings for Large Shell-Type Power Transformers Springer Theses Recognizing Outstanding Ph.D Research Aims and Scope The series “Springer Theses” brings together a selection of the very best Ph.D theses from around the world and across the physical sciences Nominated and endorsed by two recognized specialists, each published volume has been selected for its scientific excellence and the high impact of its contents for the pertinent field of research For greater accessibility to non-specialists, the published versions include an extended introduction, as well as a foreword by the student’s supervisor explaining the special relevance of the work for the field As a whole, the series will provide a valuable resource both for newcomers to the research fields described, and for other scientists seeking detailed background information on special questions Finally, it 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in that particular field More information about this series at http://www.springer.com/series/8790 Hugo Campelo FluSHELL – A Tool for Thermal Modelling and Simulation of Windings for Large Shell-Type Power Transformers Doctoral Thesis accepted by the University of Porto, Portugal 123 Author Dr Hugo Campelo Transformers R&D Department EFACEC Energia, S.A Porto Portugal Supervisors Prof José Carlos Lopes Department of Chemical Engineering Faculty of Engineering of the University of Porto Porto Portugal Prof Madalena Maria Dias Department of Chemical Engineering Faculty of Engineering of the University of Porto Porto Portugal ISSN 2190-5053 ISSN 2190-5061 (electronic) Springer Theses ISBN 978-3-319-72702-8 ISBN 978-3-319-72703-5 (eBook) https://doi.org/10.1007/978-3-319-72703-5 Library of Congress Control Number: 2017961502 © Springer International Publishing AG 2018 This work is subject to copyright All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed The use of general descriptive names, registered names, trademarks, service marks, etc in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland The only true wisdom is in knowing you know nothing Socrates To my wife Maria João, to my sons Vasco and Miguel for driving me and balancing me along this long journey Without them it would not have been so funny Last but not the least my parents who always believed in me with their hearts wide open Thank you very much for being here Supervisors’ Foreword This thesis addresses a novel application of network modelling methodologies to power transformers Network modelling is used to develop a tool to simulate the thermal performance of these machines, widely acknowledged to be critical assets in electrical networks After strong deregulation of electricity markets and decarbonization of worldwide economies, electrical networks have been changing fast Both asset owners and equipment manufacturers are being driven to develop increasingly accurate simulation capabilities to optimize either their operation or their design Temperature is a critical parameter in every electric machine, and power transformers are not an exception In this work, a novel thermal model has been developed and its simulation results verified against predictions of a commercial CFD code as well as experiments conducted in a dedicated set-up built exclusively for this purpose Hence, this work cross-links three of the most important aspects in high-quality research: model development, simulation and experimental validation Its content is relevant to a plurality of stakeholders, from utilities to power transformer manufacturers and science community in general This work was funded by a Portuguese company, EFACEC Energia, one of the world leaders in power transformer technology and represents a major milestone in a long collaboration between EFACEC and FEUP, the Engineering School of University of Porto Within this collaboration, further work has been started, namely on the development of dynamic thermal network models Porto, Portugal June 2017 Prof José Carlos Lopes Prof Madalena Maria Dias ix Abstract The current design cycle of power transformers, in general, and shell-type transformers, in particular, demands contradicting features from the design tools On the one hand, it demands faster responses, but on the other hand, it requires more detailed information to enable optimized decisions At the design stage, the thermal performance of the windings is a key characteristic to be addressed The thermal design tools currently used are targeted to determine just the average and maximum temperatures of the windings based on a reduced number of parameters and empirical factors Although useful and valid, these tools reflect the current design practices and not provide means for differentiation with innovative technological solutions Therefore, the capability of accurately predicting the detailed spatial distribution of the winding temperatures and cooling fluid velocities can be a relevant competitive advantage In this work, and to bridge this gap, a novel thermal-hydraulic network simulation tool has been first developed for shell-type windings—the FluSHELL tool Its comparison against simulations on a commercial Computational Fluid Dynamics (CFD) code reveals equivalent degrees of accuracy and detail FluSHELL shows average accuracies of 1.8 °C and 2.4 °C for the average and maximum temperatures, respectively, and the locations of the maximum winding temperatures have been consistently well predicted The fluid mass flow rate and pressure distributions show similar trends, and both can be predicted with average deviations of 20% Similar to CFD, this has been accomplished by discretizing the calculation domain into sets of smaller interconnected elements, but FluSHELL is observed to be approximately 100 times faster than a comparable CFD simulation An experimental set-up has been designed, constructed and used to prove this concept The set-up represents the closed cooling loop of a shell-type winding, and due to its operation under DC conditions, it provides means to complement the measurements of local temperatures with accurate measurements of the average temperatures The experimental validation showed predictions with the same trends and with average accuracies in the same order of magnitude of the combined uncertainties associated with the measurements Based on these results, the FluSHELL tool developed and its associated methodology are both considered conceptually validated Further applications of this tool to commercial transformers can now be envisaged xi List of Publications Parts of this thesis have been published in the following journal articles/conference proceedings: H M R Campelo, R T Oliveira, Carlos M Fonte, X M López-Fernandez, M M Dias, José Carlos B Lopes, “Modelling the Hydrodynamics of Cooling Channels inside Shell-Type Power Transformers with CFD.”, 12th International Chemical and Biological Engineering Conference, Porto, Portugal, 2014 H M R Campelo, L F Bra, X López-Fernandez, “Thermal Hydraulic Network Modelling Performance in Real Core Type Power Transformers.”, 21th International Conference on Electrical Machines, Berlin, Germany, 2014 H M R Campelo, R T Oliveira, Carlos M Fonte, M M Dias, José Carlos B Lopes, “Modelling the Hydrodynamics of Cooling Channels inside Shell-Type Power Transformers with CFD”, 3rd International Colloquium on Transformer Research and Asset Management, Split, Croatia, 2014 H M R Campelo, J P B Baltazar, R T Oliveira, Carlos M Fonte, M M Dias, José Carlos B Lopes, “Extracting Relevant Transport Properties Using CFD Simulations of Shell-Type Electric Transformers.”, ICHMT International Symposium on Computational Heat Transfer, New Jersey, USA, 2015 H M R Campelo, J P B Baltazar, C M M Carvalho, R C Lopes, R T Oliveira, Carlos M Fonte, M M Dias, José Carlos B Lopes, “SmarTHER Shell-Type Transformers: Integrating advanced thermal modelling techniques in the design-cycle.”, 5th European Conference on HV & MV Substation Equipment, Lyon, France, 2015 H M R Campelo, J P B Baltazar, C M M Carvalho, R C Lopes, R T Oliveira, Carlos M Fonte, M M Dias, José Carlos B Lopes, “Novel Thermal-Hydraulic Network Model for Shell-Type Windings Comparison with CFD and Experiments.”, Cigré Session 46, Paris, France, 2016 xiii ... degrees of accuracy and detail FluSHELL shows average accuracies of 1.8 °C and 2.4 °C for the average and maximum temperatures, respectively, and the locations of the maximum winding temperatures have... of Publications H M R Campelo, M A Quintela, J P B Baltazar, R C Lopes, C M M Carvalho, “Practical Relevance of Advanced Thermal Modelling Techniques for the Modern Design and Management of Power. .. Thermal Modelling and Simulation of Windings for Large Shell-Type Power Transformers Doctoral Thesis accepted by the University of Porto, Portugal 123 Author Dr Hugo Campelo Transformers R&D Department