Tutorial [Free for all conference attendants]
Date/Time: Monday, 6 December 2010 / 9:00am – 12:00pm
Large Wind Turbines and their Grid Connection
Dr. Janaka Ekanayake and Dr. Carlos E. Ugalde-Loo
With the increased concerns over climatic change, many countries in the world are imposing constraints on carbon emissions. The European Union has already given a directive to member countries to achieve 20% of all energy from renewable energy by 2020. In the UK in order to achieve EU directive, 35% of the electricity will be generated by renewable options. It is expected that most of which will come from wind and therefore the capacity of wind generation will rise to 30 to 40 GW by 2020.
Traditionally induction generators are employed for wind farms which are mainly onshore. However there are many limitation of these generators and they are unable to meet the grid code requirements without employing other enabling technologies. In recent years controllable renewable energy generators such as doubly-fed induction generators (DFIG) and full power converter (FPC) connected generators were emerged which are now being used extensively in onshore and offshore wind farms. With the increased size of the wind turbines, the gearless multi-pole induction generators are capturing the market interest. Many wind farm manufactures are now producing up to 5 MW of multi-pole permanent magnet wind turbines having as high as 28 poles.
Due to the variable nature of the wind power output, the utilities are imposing stringent grid connection codes. The Grid Codes specify the mandatory technical requirements that a large synchronous generator should fulfil for efficient, safe and economic operation of the power system. In addition to these mandatory requirements, power plants are expected to provide additional support to maintain a second-by-second power balance while maintaining the required level of quality and guaranteeing the security of the system. With the increasing penetration of wind power, the larger wind power plants are also now being expected to participate in the mandatory and additional services that the large synchronous generators are offering.
In this tutorial different technologies used for wind turbines are discussed. The grid code requirement of countries which has a large penetration of wind is presented and the measures taken by wind farm manufacturers to fulfil the grid code requirements are exemplified. VSC-HVDCs which are now considered as a preferred choice for connecting large offshore wind turbines is also introduced with the multi-terminal HVDC approach.
Dr. Janaka Ekanayake Ekanayake received the B.Sc.Eng. Degree in Electrical and Electronic Engineering from the University of Peradeniya in 1990 and PhD in Electrical Engineering from University of Manchester Institute of Science and Technology (UMIST), U.K. in 1995. He is presently attached to the Cardiff University, UK and is actively contributing to the research programmes of the Low Carbon Research Institute of the Welsh and the Institute of Energy of Cardiff University. Prior to that he was a Professor at the Department of Electrical and Electronic Engineering, University of Peradeniya. His main research interests include power electronic applications for power systems, renewable energy generation and its integration.
He is a Charted Engineer, Fellow of IET, Senior Member of IEEE, and Member of the IESL. He is a member of the Editorial Board of IEEE Transaction Energy Conversion. He has published more than 30 papers in refereed journals and has also co-authored three books. His recent book on Wind Turbine: Modelling and Control discusses the different wind turbine technologies and grid interconnection technologies.
Dr. Carlos E. Ugalde-Loo received the B.Sc. degree in Electronics and Communications Engineering from the Instituto Tecnologico y de Estudios Superiores de Monterrey (ITESM), Mexico, in 2002, the M.Sc. in Electrical Engineering from the Polytechnic National Institute (IPN), Mexico, in 2005, and the Ph.D. in Electronics and Electrical Engineering from the University of Glasgow, Scotland, U.K. in 2009. He is currently a Research Assistant within the Insitute of Energy of Cardiff University, UK. His research interests include power systems, FACTS devices, renewable energy generation and multivariable control.
He is a member of IET, IEEE and CIGRE.
Sponsored by: Supergen/FLEXNET
Date/Time: Monday, 6 December 2010 / 2:00pm – 5:00pm
Bi-directional and Wireless Power Technology for V2G Systems
Dr. U. K. Madawala and Dr. Duleepa Thrimawithana
Depletion of fossil fuel reserves and current practice in generation, transmission, distribution and utilization of energy are major worldwide concerns, for which distributed generation (DG) and harnessing of renewable energy are considered to be partial and acceptable solutions. However, the quality of power delivered by DG systems, especially those based on wind and solar energy, is largely affected by the stochastic nature of their energy production. Consequently, in order to improve the power quality while meeting the demand in the most economical and efficient way, energy suppliers rely on energy storage systems, particularly for DG systems of medium power levels. Amongst various storage solutions such as fly-wheels, batteries, super-capacitors etc, vehicle-to-grid (V2G) concept, which uses hybrid vehicles or pure EVs to store and supply energy back to the grid, is gaining more and more popularity as both hybrid and EVs are considered to be an indispensable component in both ‘living and mobility’ and sustainable living in near future. Irrespective of whether the EV or a fleet of EVs is used solely for medium scale energy storage or micro-scale residential use as in the case of ‘Living and Mobility’, there lies the challenge of charging and retrieval (discharging) of energy. Consequently, techniques for charging and discharging of EVs, with the emphasis on simplicity, low cost, convenience, high efficiency and flexibility, have become the main focus of current research in both industrial and academic community, whose fields of interests are in V2G and sustainable living. Contactless or wireless charging techniques have thus become a viable choice as they meet most of the above attributes.
Inductive Power Transfer (IPT) is a technology that has gained global acceptance and popularity as a technique, which is suitable for supplying power to variety of applications with no physical contacts. IPT technology transfers power from one system to another through weak or loose magnetic coupling, and offers the advantages of high efficiency, typically about 85-92%, robustness and high reliability in hostile environments being unaffected by dust or chemicals, which in fact are the key to its popularity. According to literature, many IPT systems with various circuit topologies or compensation strategies and levels of sophistication in control, have been proposed and successfully implemented to cater for a wide range of applications, which range from very low power bio-medical implants to high power battery charging system. The focus of all these reported systems has solely been improvements to the contactless power flow in unidirectional applications. Consequently, they have specifically been designed for uni-directional power flow, and thus are not suitable for applications, such as EVs, V2G systems, regenerative equipment etc, which require bi-directional power flow.
This tutorial provides an introduction to IPT Technology with particular emphasis on bi-directional IPT concept, which is suitable for simultaneous contactless charging/discharging and grid integration of multiple EVs used in V2G systems. The tutorial intends to cover material in such a way that participants will gain valuable knowledge in relation to applications, theory and analysis of both unidirectional and bidirectional IPT Systems.
Dr. Udaya K. Madawala (Senior Member IEEE) graduated with B. Sc. (Electrical Engineering) (Hons) from The University of Moratuwa, Sri Lanka in 1987 and received his PhD (Power Electronics) from The University of Auckland, New Zealand in 1993. He was employed by Fisher & Paykel Ltd, New Zealand as a Research and Development Engineer in 1993, and he joined the Department of Electrical and Computer Engineering at The University of Auckland, New Zealand, as a Research Fellow and worked on energy related various power electronics projects. At present, he is a full-time Senior Lecturer, and serves as an Associate Editor for IEEE Transactions on Industrial Electronics, IEEE Transactions on Power Electronics and International Journal on Industrial Electronics and Motor Drives. He is a member of the Power Electronics Technical Committee and the Chairman of the sub-committee of Power Electronic Converters of the IEEE Industrial Electronic Society, and also the Chairman of the Joint Chapter of IEEE Industrial Electronics and Industrial Applications Society, New Zealand (North). He has more than 100 international publications and 4 patents. His research interests are in the fields of renewable or green energy, power electronics and inductive power transfer, and he works as a consultant to industry in these fields.
Duleepa J. Thrimawithana (Member IEEE) graduated with B. E. (Electrical Engineering) (1st class Hons.) from The University of Auckland, New Zealand in 2005. He received his PhD (Power Electronics) from the same university in 2009. From 2005 to 2008 he worked, in collaboration with Tru-Test Ltd, New Zealand as a research engineer in the areas of power converter and high voltage pulse generator design. In 2008 he joined the Department of Electrical and Computer Engineering at the University of Auckland as a part-time lecturer. During this time he worked in collaboration with the Department of Energy Technology, Aalborg University, Denmark and was involved in modeling of micro-grids and vehicle to grid interface systems. At present he is working as a fulltime lecturer and a research fellow at the department of Electrical and Computer Engineering, University of Auckland, New Zealand. His main research areas are in the fields of inductive power transfer systems and power electronic converters that are suitable for green energy applications.
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