Modeling & Analysis of Small Hydroelectric Generation and Battery Energy Storage Connected as a Microgrid Kelly Kozdras A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering University of Washington 2016 Committee: Daniel S. Kirschen Baosen Zhang Program authorized to offer degree: Electrical Engineering ProQuest Number: 10138844 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. ProQuest 10138844 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 ©Copyright 2016 Kelly Kozdras 2 University of Washington Abstract Modeling & Analysis of Small Hydroelectric Generation and Battery Energy Storage Connected as a Microgrid Kelly Kozdras Chair of the Supervisory Committee: Close Professor of Electrical Engineering, Dr. Daniel Kirschen Electrical Engineering Interest in battery energy storage continues to grow as a way to realize a variety of benefits in complement to their ability to store energy, including incorporation in microgrids that can operate in parallel with or completely isolated from the larger power grid. This paper considers small hydroelectric generation and battery energy storage connected as a microgrid. The specific project studied is located in the mountains of Washington State, and the microgrid analyzed could provide backup power to a small town that experiences frequent power outages. A dynamic model is generated and a transient stability analysis of the system is performed to study whether it remains stable if operated as the proposed microgrid. In particular, the ability of the battery energy storage to provide frequency regulation to the generator is considered. 3 Acknowledgement: The information, data, or work presented herein was funded in part by the Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy, under Award Number DE‐ EE0002668 and the Hydro Research Foundation. Disclaimer: The information, data or work presented herein was funded in part by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes and warranty, express or implied, or assumes and legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 4 Contents Table of Figures ............................................................................................................................... 6 1. Introduction ............................................................................................................................. 8 1.1. Battery energy storage systems ....................................................................................... 8 1.2. Small hydroelectric generation ...................................................................................... 11 1.3. Microgrids ...................................................................................................................... 12 1.4. Transient stability ........................................................................................................... 14 2. Problem Description .............................................................................................................. 16 2.1. Puget Sound Energy project description ........................................................................ 16 2.2. Description of this project .............................................................................................. 18 3. Method .................................................................................................................................. 20 3.1. Modeling & analysis in PowerWorld .............................................................................. 20 3.2. Generator model ............................................................................................................ 21 3.3. Exciter model .................................................................................................................. 23 3.4. Governor model ............................................................................................................. 26 3.5. Transmission & distribution model ................................................................................ 28 3.6. Battery energy storage system model ........................................................................... 28 4. Results .................................................................................................................................... 33 4.1. Transient stability analysis without BESS ....................................................................... 33 4.2. BESS parameter tuning ................................................................................................... 38 4.3. Transient stability studies with BESS.............................................................................. 42 5. Conclusions and Future Work ............................................................................................... 47 5.1. Conclusions..................................................................................................................... 47 5.2. Future work .................................................................................................................... 49 Appendix A .................................................................................................................................... 52 Appendix B .................................................................................................................................... 54 5 Table of Figures Figure 1: Possible applications of energy storage systems [1] ....................................................... 8 Figure 2: Battery energy storage system schematic [1] ............................................................... 10 Figure 3: Example small‐scale run‐of‐river hydroelectric system [5] ........................................... 11 Figure 4: Example microgrid schematic [8] .................................................................................. 13 Figure 5: Proposed microgrid in Glacier, WA ................................................................................ 17 Figure 6: Map of proposed microgrid in Glacier, WA [17] ............................................................ 18 Figure 7: GENSAL block diagram [20] ........................................................................................... 22 Figure 8: Power generation system block diagram [11] ............................................................... 24 Figure 9: IEEET1A block diagram [20] ........................................................................................... 26 Figure 10: Pelton wheel high‐head turbine [11] ........................................................................... 26 Figure 11: IEEEG1 block diagram [20] ........................................................................................... 27 Figure 12: Simple BESS model [26] ............................................................................................... 29 Figure 13: REPC_A active power control block diagram [20] ....................................................... 31 Figure 14: Existing system with default exciter & governor settings (T3 = 0.1 s) ......................... 35 Figure 16: Existing system with default exciter settings & governor T3 = 0.25 s .......................... 37 Figure 17: Generator speed with default exciter settings & governor T3 = 0.25 s ....................... 37 Figure 18: Generator electrical power output with BESS Kpg = 1 ................................................. 40 Figure 19: Generator rotor speed with BESS Kpg = 1 .................................................................... 40 Figure 20: BESS output with BESS Kpg = 1 ..................................................................................... 41 Figure 21: Summary of microgrid transient stability simulations ................................................ 42 Figure 22: Generator electrical power output, 25% load increase (simulation 2) ....................... 44 Figure 23: Generator rotor speed, 25% load increase (simulation 2) .......................................... 44 Figure 24: Load bus voltage, BESS internal voltage is 1.0 p.u. (simulation 2) .............................. 45 Figure 25: Load bus voltage, BESS internal voltage > 1.0 p.u. (simulation 3) ............................... 45 Figure