Analysis of Integration of Plug-In Hybrid Electric Vehicles in the Distribution Grid
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Analysis of Integration of Plug-in Hybrid Electric Vehicles in the Distribution Grid Ahmad Karnama Master of Science Thesis Stockholm, Sweden 2009 Analysis of Integration of Plug-in Hybrid Electric Vehicles in the Distribution Grid Ahmad Karnama Thesis for rewarding Master of Science Degree in Electric Power Engineering from School of Electrical Engineering at Royal Institute of Technology (KTH), Stockholm, Sweden. Involved Academic Divisions: Electric Power Systems Electrical Machines and Power Electronics Academic Supervisors: Professor Lennart Söder Professor Stefan Östlund Industrial Partner: Fortum Distribution AB Industrial Supervisors: Mr. Olle Hansson Mr. Jonas Tosting Examiner: Professor Lennart Söder [II] در ر وزه ری رم دوش ددم دو ھزار وزه و و وش وزه رآورد روش و وزه ر و وزه ر و وزه روش Once, in a potter's shop, a company Of cups in converse did I chance to see, And lo! One lifted up his voice, and cried, "Who made, who sells, who buys this crockery? " 1 ,born 1048 AD, Neyshapur, Iran—1123 AD, Neyshapur) ,( ر م :From Omar Khayyam (Persian 1 Iran), a Persian polymath, mathematician, philosopher, astronomer and poet. [III] [IV] Abstract The new generation of cars are so-called Plug-in Hybrid Electric Vehicles (PHEVs) which has the grid connection capability. By the introduction of these vehicles, the grid issues will be connected to the private car transportation sector for the first time. The cars from the gird perspective can be considered as a regular load with certain power factor. The effects of this type of new load in distribution grid are studied in this thesis. By modelling the cars as regular load, the effects of the cars in three distinct areas in Stockholm are investigated. The car number in each area is estimated based on the population and commercial density of electricity consumption in the three areas. Afterward, the average electricity consumption by the cars in one day is distributed among 24 hours of the day with peak load in the studied year. This distribution is done by two regulated and unregulated methods. The regulated method is based on the desired pattern of electricity consumption of PHEVs by vehicle owners. On the other hand, the regulated pattern is designed based on encouragement of the car owners to consume electricity for charging their car batteries at low-power hours of day (usually midnight hours). The power system from high voltage lines in Sweden down to 11 kV substations in Stockholm simulated in PSS/E software has been used in this study. The automation program (written in Python) is run in order to get the output report (voltage variation and losses) of the load flow calculations for different hours of day by adding the required power for PHEVs both by regulated and unregulated patterns. The results show the possibility of introducing growing number of cars till year 2050 in each area with existing grid infrastructures. Moreover, the number of cars, yearly and daily electric consumption for PHEVs in pure electric mode are shown in this project and the effects of regulated electricity consumption are investigated. It is concluded that since the car number is estimated based on the population, the areas with higher residential characteristics are more problematic for integration of PHEVs from capacity point of view. Moreover, by regulating the charging pattern of PHEVs, the higher number of PHEVs can be integrated to the grid with the existing infrastructures. In addition, the losses have been decreased in regulated pattern in comparison with unregulated pattern with the same power consumption. The voltage in different substations is within the standard boundaries by adding 100 percent of PHEVs load for both regulated and unregulated patterns in all three areas. Keywords Plug-in Hybrid Electric Vehicles (PHEVs), grid integration, voltage variation, PSS/E, program automation in PSS/E by Python, valley filling, demand side management [V] [VI] Acknowledgements This thesis was performed in cooperation with Fortum Distribution AB and divisions of Electric Power Systems and Electrical Machines and Power Electronics in School of Electrical Engineering at Royal Institute of Technology (KTH). My special thanks go to my academic supervisors; Professor Stefan Östlund and Professor Lennart Söder. The idea of the thesis was initiated during the summer internship which I did with supervision of Professor Östlund. Moreover, his valuable comments and positive energy despite of his busy schedule was always the greatest assistance for me. From the power system side, I have to confess that I was fortunate that I had Professor Söder’s supervision. He was always welcome to answer my questions and his comments formed my way of thinking to do the thesis. I want to kindly appreciate Dr. Valerijs Knazkins my former supervisor who is now in ABB in Switzerland and Dr. Mehrdad Ghandhari for his comments and assistants. I really enjoyed the friendly environment in Fortum Distribution AB together with nice place and enough facilities to do my thesis. My special thank go to my industrial supervisors in Fortum; Mr. Olle Hansson and Mr. Jonas Tosting. Thank you so much Mr. Hansson for trusting me, for productive discussions and meetings and for invaluable comments. Thanks you Mr. Tosting for practical comments and discussions on business side of my thesis. I learned a lot with exceptional assistance from my industrial supervisors in Fortum’s nice work environment. I would like to kindly appreciate Fortum employees for their kind behavior and their undeniable help during my thesis. I want to specially thank Mr. Anders Ekberg, Ms. Marie Fossum, Mr. Daniel Terranova, Mr. Oskar Engblom, Ms. Emilia Käck, Mr. Christer Bergerland, Mr. Stefan Råstrom, Mr. Jan-Rune Thun, Mr. Thomas Josefsson and Mr. Åke Norman for productive discussions and invaluable assistance during my thesis. At last but not the least I want to thank my great family and specially my beloved parents in Iran for all their supports and understandings. Although I am physically far from them but their positive energy is continuously passing the 4535 km of distance between Kerman and Stockholm. Ahmad Karnama ا ر August 2009 [VII] [VIII] Table of Contents Abstract ................................................................................................................ V Acknowledgements ............................................................................................. VII Table of Contents ................................................................................................. IX List of Figures ...................................................................................................... XII List of Tables ...................................................................................................... XIV CHAPTER 1 ............................................................................................................ 1 Introduction .......................................................................................................... 1 1.1 Background ..................................................................................................... 1 1.2 How did the thesis get started? ........................................................................ 1 1.3 Thesis Description ............................................................................................ 3 1.4 Report Outline ................................................................................................. 4 CHAPTER 2 ............................................................................................................ 6 Transition from conventional vehicles to PHEVs ..................................................... 6 2.1 History ............................................................................................................. 6 2.2 Introduction ..................................................................................................... 7 2.3 Different types of vehicles ................................................................................ 8 2.3.1 Conventional vehicles ................................................................................ 8 2.3.2 Hybrid electric vehicles .............................................................................. 9 2.3.3 Plug-in Hybrid Electric Vehicles .................................................................. 9 CHAPTER 3 .......................................................................................................... 11 Plug-in Hybrid Electric Vehicles ............................................................................ 11 3.1 Why PHEV? .................................................................................................... 11 3.2 Comparison between a HEV and a PHEV ........................................................ 12 3.3.2 Available EV and PHEVs in the market ..................................................... 14 CHAPTER 4 .......................................................................................................... 17 PSS/E and Simulation Automation in PSS/E .......................................................... 17 4.1 PSS/E introduction ......................................................................................... 17 4.2 Static analysis of the power system in PSS/E .................................................. 19 4.3 Automation tools in PSS/E ............................................................................. 21 4.4 Automation program