Hydroelectric Power Generation and Distribution Planning Under Supply Uncertainty
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Hydroelectric Power Generation and Distribution Planning Under Supply Uncertainty by Govind R. Joshi A Thesis Submitted to The Department of Engineering Colorado State University-Pueblo In partial fulfillment of requirements for the degree of Master of Science Completed on December 16th, 2016 ABSTRACT Govind Raj Joshi for the degree of Master of Science in Industrial and Systems Engineering presented on December 16th, 2016. Hydroelectric Power Generation and Distribution Planning Under Supply Uncertainty Abstract approved: ------------------------------------------- Ebisa D. Wollega, Ph.D. Hydroelectric power system is a renewable energy type that generates electrical energy from water flow. An integrated hydroelectric power system may consist of water storage dams and run-of-river (ROR) hydroelectric power projects. Storage dams store water and regulate water flow so that power from the storage projects dispatch can follow a pre-planned schedule. Power supply from ROR projects is uncertain because water flow in the river, and hence power production capacity, is largely determined by uncertain weather factors. Hydroelectric generator dispatch problem has been widely studied in the literature; however, very little work is available to address the dispatch and distribution planning of an integrated ROR and storage hydroelectric projects. This thesis combines both ROR projects and storage dam projects and formulate the problem as a stochastic program to minimize the cost of energy generation and distribution under ROR projects supply uncertainty. Input data from the Integrated Nepal Power System are used to solve the problem and run experiments. Numerical comparisons of stochastic solution (SS), expected value (EEV), and wait and see (W&S) solutions are made. These solution approaches give economic dispatch of generators and optimal distribution plan that the power system operators (PSO) can use to coordinate, control, and monitor the power generation and distribution system. The W&S solution approach provided the least cost plan. The EEV solution was worse than the SS. The PSO may invest in advanced technologies to more accurately reveal the uncertainties in the planning process, to operate at the W&S operational cost. However, the tradeoff between using the SS solution and investing in new technologies to operate at W&S solution may require rigorous feasibility study. ii Certificate of Acceptance This thesis presented in partial fulfillment of the requirements for the degree of Master of Science has been accepted by the program of Industrial and Systems Engineering, Colorado State University - Pueblo APPROVED --------------------------------------------------------------------------------------------------------------------- Dr. Ebisa D. Wollega Date Assistant Professor of Engineering and Committee Chair --------------------------------------------------------------------------------------------------------------------- Dr. Leonardo Bedoya-Valencia Date Associate Professor of Engineering and Committee Member --------------------------------------------------------------------------------------------------------------------- Dr. Jane M. Fraser Date Professor and Director of Engineering and Committee Member Master’s Candidate Govind R. Joshi Date of thesis presentation December 16, 2016 iii ACKNOWLEDGEMENTS This thesis would not have been possible without the guidance and the help of several individuals who contributed and extended their valuable assistance in the preparation and completion of this research. First and foremost, I offer my utmost gratitude to my academic advisor and committee chair, Dr. Ebisa Wollega, for his support throughout the development of this thesis with his knowledge and patience. I also would like to thank the Department of Engineering at Colorado State University -Pueblo for giving me the opportunity to work on this thesis and for providing me the required resources to carry out this research. Last but not the least, I would like to thank my parents as well as my uncle Rajendra Awasthi and aunt Kacie Awasthi for their guidance and support throughout my master degree at Colorado State University - Pueblo. iv ABBREVIATIONS Table I List of abbreviations Current measurement unit A (Amperes) MWhr/MWh Mega Watt Hour AC Alternating Current NEA Nepal Electricity Authority AI Artificial Intelligence OPF Optimal Power Flow CF Capacity Factor pf power factor DC Direct Current PF Plant Factor DGs Distributed Generators PP Power Plant DL Distribution Line Q Water discharge Expectation of Expected Water discharge during dry EEV Value Qdry season Water discharge during wet FY Fiscal Year Qwet season H Head or Height ROR Run-of -River HEP Hydroelectric Project SS Stochastic Solution Integrated Nepal Power INPS System TL Transmission Line kV Kilo Volts TP Transportation Problem Active power measurement unit LOLP Loss of Load Probability W (Watts) MW Mega Watts W&S Wait and See v LIST OF FIGURES Figure 1.1 Power system network block diagram consisting of hydroelectric power projects. ..... 5 Figure 2.1 Integrated power system ................................................................................................ 7 Figure 3.1 Electromechanical governor ........................................................................................ 34 Figure 3.2 Integrated power system network ................................................................................ 37 Figure 4.1 Plant factors of the ROR projects ................................................................................ 43 Figure 4.2 Monthly energy generation by the ROR projects. ....................................................... 44 Figure 4.3 Seasons of a year in the INPS..................................................................................... 45 Figure 4.4 Decision variable values from EEV approach. ............................................................ 52 Figure 4.5 Decision variable values from SS approach. ............................................................... 54 Figure 4.6 Decision variable values from W&S approach. .......................................................... 56 Figure A.1 Integrated Nepal Power System map………………………………………………...68 Figure A.2 Integrated Nepal Power System single line diagram………………………………...69 Figure A.3 MATLAB simulation diagram of the Integrated Nepal Power System……………..69 Figure B.1 Monthly energy generation by the ROR projects in Nepal………………………….71 Figure B.2 Total monthly energy generation by the ROR projects in Nepal……………………73 Figure B.3 Average monthly plant factor or the ROR projects in Nepal (in Percentage)……….74 Figure C.1 Hourly peak demand in the INPS……………………………………………………75 Figure E.1 MATLAB and PSAT results for bus voltages in the INPS………………………….79 Figure E.2 INPS bus voltage level for each season……………………………………………...80 vi LIST OF TABLES Table I List of abbreviations .......................................................................................................... vi Table 3.1 Notation ........................................................................................................................ 25 Table 4.1 Existing major hydroelectric power plants and their types (source: NEA [56]) .......... 42 Table 4.2 Nepali to English calendar conversion ......................................................................... 44 Table 4.3 Seasons in a year and their probabilities ....................................................................... 46 Table 4.4 Existing transmission and distribution lines capacity in the INPS .............................. 47 Table 4.5 Existing substations in the INPS and their capacities ................................................... 49 Table 4.6 Cost parameter computation ......................................................................................... 50 Table 4.7 Total operation and maintenance cost from the NEA report ........................................ 51 Table 4.8 Legend .......................................................................................................................... 52 Table 4.9 The objective function values from SS, W&S, and EEV approach ............................. 59 Table C.1 Current power supply and demand in Nepal………………………………………….75 Table D.1 Cost and capacity parameters computation of the power system components……….76 vii TABLE OF CONTENTS ABSTRACT .................................................................................................................................. II ACKNOWLEDGEMENTS ....................................................................................................... IV ABBREVIATIONS ...................................................................................................................... V LIST OF FIGURES .................................................................................................................... VI LIST OF TABLES .................................................................................................................... VII CHAPTER 1. INTRODUCTION ................................................................................................ 1 1.1. BRIEF OVERVIEW .................................................................................................................. 1 1.2. RESEARCH MOTIVATION ....................................................................................................... 2 1.3. OBJECTIVE OF THE STUDY ....................................................................................................