National Cheng Kung University Department of Electrical Engineering Tainan City, Tarwan, R O C Master of Science Thesis Dynamic-Stability Improvement of a Multi-machine Power System connected with a Large-scale Offshore Wind Farm Using a Generalized Unified Power Flow Controller Student: Advisor: Nguyen Thị Ha Li Wang July 2014 Dynamic-Stability Improvement of a Multi-machine Power System connected with a Large-scale Offshore Wind Farm Using a Generalized Unified Power Flow Controller Nguyen Thi Ha* and Li Wang** Department of Electrical Engineering National Cheng Kung University Tainan City, Taiwan, R O C Abstract This thesis studies the dynamic-stability improvement of a multi-machine system connected with a large-scale offshore wind farm based on doubly-fed induction generator (DFIG) using a generalized unified power-flow controller (GUPFC) A twoarea four-generator system model Two is employed as the studied multi-machine proportional-integral-derivative (PID) damping controllers (FLCs) of the proposed GUPFC system controllers and two fuzzy logic are respectively designed to improve the stability of the studied multi-machine power system connected with the offshore wind farm under different operating conditions A frequency-domain approach based on a linearized system model using eigenvalue analysis and a time-domain method based on nonlinear-model simulations subject to various disturbances are both performed to examine the effectiveness of the proposed GUPFC combined with the designed damping controllers It can be concluded from the comparative simulation results that the proposed GUPFC joined with the designed FLCs demonstrates better damping performance for improving the stability of the studied multi-machine system subject to different disturbances than the designed PID damping controllers Keywords: Multi-machine generalized system, unified power-flow AC transmission systems * The student ** The advisor wind farm, doubly-fed controller, induction dynamic generator, stability, flexible ACKNOWLEDGEMENTS First of all, I would like to express my deep gratitude to my advisor Professor Li Wang for his help, his advice and his teaching His valuable suggestions, his encouragement and his patience have been a big help for me over the last time I am very grateful to all Professors in Power Group of Electrical Engineering Department, National Cheng Kung University (NCKU) as well as Professors from other Universities for their teaching, encouragement, and valuable comments I also would like to thank my colleagues at the laboratory for the enjoyable discussions and friendly atmosphere Furthermore, I would like to extend my deepest gratitude and personal thanks to those closest to me In particular, | would like to thank my families for their support, encouragement and understanding Last but not least, I would like to say special thanks to the NCKU Scholarship Program for giving me the opportunity to work on a highly studying environment and for their financial support Nguyen Thi Ha H LIST OF CONTENTS 0i ốốốốĂ 0401/50/2510 I 27777 List Of COTI{€TIẨS Q2 1112111112111 111 1111111111111 11111111 List Of fIQ™UIES H KH KH kg II mnDDD VI 880: 1): x Nomenclature 0cccccccccccccscceeseceesceeceeeceseeeeeeeeeecessceecsseeceseeeseeesesaeeesseeseneeeseesenseeens XII IO8oe¿ 19175 Chapter Ín{FOđUCẨTOTN XIV c0 55 6 95 96 999999 09.64 9.96 088988999996 9696608686889999999969606 LoL Motivation cccccccccccccsceeneccesceccsseeeceeeceeeeseneeeesseeesseeeesseeceseeeeseeeeseeeeseesseeseses | 1.2 Literature i22 1.2.1 Topics of DFIG-based OWFES QQQQ TQ n Q.2 HH HH SH HT HH nh 1.2.2 Topics 006/00 1)90 1.3 Contribution of the fheSI1S 1.4 Outline of the th€S1S c1 c1 2121101111211 15521 111111111111 1211 111111 81k rệt 1221111211 1121111 511115 111111111111 111 11H k KH kkt Chapter Configuration Of the SVSÍCITI co 5< < G5 9699999909996 996060886886669996969666 2.1 Configuration of the sysf†em - - c1 211111122211 1111115011111 ng ngu 2.2 Two-area four-generator system and 1ts subsysfems -s+cc+