Contents 1 Introduction 1 1.1 Why Is Flexibility Necessary for the Power System 1 1.2 Overview of Power System Flexibility 2 1.2.1 History and Development 2 1.2.2 Taxonomy-Power System Flexibility Sources 4 1.2.3 Power System Flexibility Analysis 5 1.3 Market Solutions 6 1.4 Summary 7 References 8 2 Power System Flexibility Modelling 9 2.1 Introduction 9 2.2 Power System Flexibility Resource Classification 11 2.2.1 Demand Side Flexibility Resources 11 2.2.2 Power Supply Side Flexibility Resources 11 2.2.3 Grid Side Flexibility Resources 13 2.3 Flexible Power Supply Resources: Analysis and Modelling 13 2.3.1 Technical Characteristics of Flexible Power Supply Resources 14 2.3.2 Economic Characteristics of Power Supply Resources Flexibility 20 2.4 Demand Side Flexibility Model 21 2.4.1 Interruptible Load 22 2.4.2 Adjustable Load 22 2.4.3 Shiftable Load 24 2.5 Power Grid Flexible Regulation Technologies 25 2.5.1 Voltage Source Converter (VSC) Based Multiple-Terminal DC Transmission 25 2.5.2 AC Grid Flexible Topology Control 27 2.6 Conclusions 28 References 29 3 Flexibility-Based Economic Dispatch 31 3.1 Introduction 31 3.2 Quantifying Accommodated Domain of Wind Power for Flexible Look-Ahead Unit Commitment 33 3.2.1 Formulation of ADWP 33 3.2.2 Flexible Look-Ahead Unit Commitment Models 37 3.3 Flexibility Based Day-Ahead Generation–Reserve Bilevel Decision Model 42 3.3.1 Day-Ahead Unit Commitment Model Considering Flexibility Constraint 42 3.3.2 Flexibility Based Reserve Decision Method 45 3.4 An Endogenous Approach to Quantifying the Wind Power Reserve 51 3.4.1 Dynamic S&NCED Model with AARO 52 3.4.2 Two-Stage Solution Method Based on the Benders Decomposition 55 3.5 Case Studies 60 3.5.1 Case Studies of the Flexible Look-Ahead Unit Commitment 60 3.5.2 Case Studies of the Day-Ahead Generation-Reserve Bilevel Decision Model 66 3.5.3 Case Studies of the Endogenous Approach to Quantifying theWind Power Reserve 73 3.6 Conclusion 77 References 78 4 Distributed Dispatch Approach in AC/DC Hybrid Systems 81 4.1 Introduction 81 4.2 Distributed Dispatch Approach in Bulk AC/DC Hybrid Systems 83 4.2.1 Distributed Scheduling Framework for Bulk AC/DC Hybrid Transmission Systems 83 4.2.2 Improved ATC-Based Distributed SCUC for a Bulk AC/DC Hybrid System 86 4.2.3 Solution Procedure 91 4.3 Distributed Dispatch Approach in the VSC-MTDC Meshed AC/DC Hybrid Systems 94 4.3.1 Hierarchy of VSC-MTDC Meshed AC/DC Grid 94 4.3.2 Hierarchical and Robust Scheduling Formulation 98 4.3.3 Solution Methodology 103 4.4 Case Studies 107 4.4.1 Distributed Dispatch Approach in Bulk AC/DC Hybrid Systems 107 4.4.2 Distributed Dispatch Approach in VSC-MTDC Meshed AC/DC Hybrid Systems 115 4.5 Conclusion 122 References 122 5 Exploring Operational Flexibility of AC/DC Power Grids 125 5.1 Introduction 125 5.2 Improving Flexible Operation of MTDC Hybrid Networks by VSC Power Regulation 126 5.2.1 Problem Description 126 5.2.2 Flexible Operation Mechanism and Model 128 5.2.3 Flexible Operation Improvement Mode for VSC Station 135 5.3 Exploiting the Operational Flexibility of Wind Integrated Hybrid AC/DC Power Systems 141 5.3.1 SCED Model with TS for Hybrid AC/DC Grid 141 5.3.2 Two-Stage RO Based on C&CG 144 5.4 Case Studies 147 5.4.1 Verify of Power Margin Tracking Droop Regulation(PMT)Mode 147 5.4.2 Exploring Operational Flexibility of AC/DC Power Networks Using TS 152 5.5 Conclusion 156 References 157 6 Demand Side Flexibility 159 6.1 Introduction 159 6.2 Residential Load Demand Response Model 161 6.3 Price-Based Demand Response Model 163 6.3.1 Energy Management Model of the ITCA 164 6.3.2 Flexibility of ITCAs 166 6.3.3 ITCAs’ Flexibility Under TOU Power Price 169 6.3.4 Unit Scheduling Model Considering the Flexibility of ITCAs 170 6.4 Integrated Energy System Demand Response Model 173 6.4.1 Typical Topology 174 6.4.2 Integrated Demand Response Model 175 6.4.3 Two-Stage Stochastic Chance-Constrained Programming Model 179 6.5 Case Studies 185 6.5.1 Residential Load Demand Response 185 6.5.2 Price-Based Demand Response Model 188 6.5.3 Integrated Energy System Demand Response 191 6.6 Conclusion 197 References 198 7 Large-Scale Distributed Flexible Resources Aggregation 199 7.1 Introduction 199 7.2 Large Scale Interruptible and Shiftable Load Aggregation 202 7.2.1 Equivalent Aggregated Model for Large-Scale Interruptible and Shiftable Loads 202 7.2.2 Equivalent Model for a Single Group 203 7.2.3 Scheduling with Equivalent Aggregated Model 213 7.3 Large Scale EV Aggregation 217 7.3.1 Market Framework 217 7.3.2 Aggregate Model of Electric Vehicle Fleets 218 7.3.3 Model of Optimal Bidding Strategy of Microgrid 223 7.4 Case Study 226 7.4.1 Large Scale Interruptible and Shiftable Load Aggregation 226 7.4.2 Large Scale Distributed Energy Storage Aggregation 233 7.5 Conclusion 237 References 238 8 Market Mechanism Design for Enhancing the Flexibility of Power Systems 241 8.1 Introduction 242 8.2 The Framework of Balancing Market 243 8.2.1 The Framework of Balancing Market 243 8.2.2 Key Design Elements in Imbalance Settlement 244 8.3 System Model 247 8.3.1 Balancing Market Clearing Optimization Model Embedded with the Offering Strategy of Wind Power Producers 247 8.3.2 Offering Strategy of the Wind Power Producer 248 8.3.3 Objective Function and Constraints 248 8.3.4 SolutionMethod 250 8.3.5 ABMMethod 251 8.3.6 TheMCDA Evaluation 255 8.4 Case Studies 261 8.4.1 Analysis of Wind Power Supplier’s Strategic Offering 261 8.4.2 Analysis of Strategic Interaction Behavior of Market Players 265 8.5 Conclusion 269 References 270