1 Introduction: Basic Assumptions and Concepts -- 1.1 Importance of the envisioned control structures in a changing industry -- 1.2 System regulation issues affected by the vertical separation of the transmission grid from generation -- 1.3 Organization of this text -- 2 The Nested Hierarchy as a System Structure in a Changing Industry -- 2.1 Principles of existing horizontally structured electric power systems -- 2.2 Industry changes leading to the nested hierarchy structure -- 2.3 Examples of new industry arrangements as particular cases of the nested hierarchy structure -- 2.4 The need for new control structures -- 2.5 Can generation-based regulation be made price-competitive? -- 2.6 Relevance of dynamic problem formulation over mid- and long-term horizons -- 3 Performance Criteria Relevant to Operating Interconnected Electric Power Systems -- 3.1 Dynamics of system inputs to which the control responds -- 3.2 Time frames for present performance objectives -- 3.3 Modeling for systems control services in a changing industry -- 3.4 Performance criteria at the subsystem level -- 3.5 Static optimization in an open access system -- 3.6 Static optimization of a horizontally structured system -- 3.7 Present criteria for mid- and long-term dynamic performance -- 3.8 Static performance criteria for reactive power/voltage support -- 3.9 Summary -- 4 Structural Modeling and Control Design Using Interaction Variables -- 4.1 Structural modeling -- 4.2 Hierarchical control design -- 4.3 Tertiary level coordination -- 4.4 New tertiary-level aggregate model -- 4.5 Comparison of the proposed control structures to those used at present -- 4.6 Summary -- 5 Generation-Based Regulation of Real Power/Frequency -- 5.1 State of the art and potential problems of frequency regulation -- 5.2 New modeling -- 5.3 Analysis -- 5.4 Model derivations -- 5.5 Control design -- 5.6 Summary -- 6 Generation-Based Regulation of Reactive Power/Voltage -- 6.1 Modeling -- 6.2 Quasi-static voltage model -- 6.3 Quasi-static interaction variables -- 6.4 Voltage regulation -- 6.5 Regional voltage control -- 6.6 Tertiary coordination -- 6.7 New tertiary level-aggregate models -- 6.8 Summary -- 7 The Value of Generation-Based Regulation: Competition Versus Coordination -- 7.1 Relevant optimality questions for determining the value of control services -- 7.2 Control-dependent values of subsystems in a competitive environment -- 7.3 Systems control structure-related issues -- 7.4 Long-term stability of decentralized systems control services -- 7.5 Achievable optimality as a function of the level of control co-ordination -- 7.6 Limitations of existing systems control in a competitive environment -- 7.7 Proposed approach to real-time systems control and its pricing in a competitive market -- 7.8 Summary -- 8 Network-Based System Regulation -- 8.1 Engineering issues and opportunities in operating power transmission grids of the future -- 8.2 Recent changes affecting the transmission grid and their relation to the basic engineering issues -- 8.3 A brief review of the present principles for regulating a transmission grid and the power system -- 8.4 The basic planning problem on a transmission grid -- 8.5 Operating problems using mechanically switched reactive devices -- 8.6 Opportunities and problems presented by very fast regulation of the transmission grid: FACTS trends -- 8.7 Direct flow control via FACTS devices -- 8.8 Summary -- 9 Conclusions -- 9.1 Summary of our approach to linking technical and economic processes under competition -- 9.2 Relevance of our proposed modeling and control framework -- 9.3 A Final Word.