Advanced Load Dispatch for Power Systems

1. Introduction.- 1.1 Development of Interconnected Power Systems.- 1.2 Benefits of Operation of Interconnected Power Systems.- 1.2.1 Reduction in Generating Capacity Due to the Diversity of Load Demands.- 1.2.2 Reduction in Standby Capacity.- 1.2.3 Increase in the Size of Generating Sets.- 1.2.4 Optimum Utilisation of the Available Plant Capacity and Transmission Facilities.- 1.2.5 Reliability of Power Supply.- 1.2.6 Improvement in Frequency.- 1.3 Developing and Developed Systems.- 1.3.1 India.- 1.3.2 UCPTE.- 1.3.3 Indian Grid Systems.- 1.3.4 The UCPTE System.- 1.4 Human Factors in the Operation of Interconnected Power Systems.- 1.4.1 Mutual Trust.- 1.4.2 Understanding Problems Peculiar to Constituents.- 1.4.3 Effective Communication.- 2. Objectives, Functions and Location of Load Dispatch Centres.- 2.1 Objectives.- 2.2 Operational Planning.- 2.3 Functions.- 2.3.1 Programming.- 2.3.1.1 Load Forecasting.- 2.3.1.2 System reserve.- 2.3.1.3 Daily generation scheduling.- 2.3.1.4 Reactive power.- 2.3.2 System Monitoring.- 2.3.3 System Control.- 2.4 Hierarchical Set-Up of Load Dispatch Centres.- 2.4.1 Great Britain.- 2.4.2 France.- 2.4.3 India.- 2.5 Location of Load Dispatch Centres.- 3. Facilities at Load Dispatch Centres.- 3.1 Equipment and General Arrangement.- 3.2 Building.- 3.3 Control Room.- 3.3.1 Mosaic Diagram.- 3.3.2 Computerised Display.- 3.3.3 Control Desks and Instrument Consoles.- 3.4 Computer System.- 3.5 Teleprinter Facilities.- 3.6 Weather Information System.- 3.7 Operational Data Logging.- 3.7.1 Service Logs and Records.- 3.7.2 Loading Log.- 3.7.3 Measured Value Log.- 3.7.4 Switching Log.- 3.7.5 Generation Plant Availability.- 3.7.6 Energy Generation.- 3.7.7 Inter-System Energy Transfers.- 3.7.8 Reservoir Levels, Inflows, etc..- 3.7.9 Fuel Consumption and Stocks.- 3.8 Auxiliary Power Supply.- 3.8.1 DC Battery System.- 3.8.2 AC Stabilised Supply.- 3.8.3 Uninterruptible Power Supply (UPS).- 3.8.4 Diesel-Generator Set.- 3.8.5 HVAC System.- 3.8.6 A Case Study.- 3.9 Training of System Operators.- 3.9.1 General.- 3.9.2 Placement of Staff.- 3.9.3 Training Facilities.- 3.9.3.1 Workshops.- 3.9.3.2 Simulator Training.- 3.9.3.3 Computer-based training (CBT).- 4. Telecommunications in Power System Operation.- 4.1 General.- 4.2 Communication Systems.- 4.2.1 Power Line Carrier Communication (PLCC).- 4.2.2 Microwave Communication.- 4.2.3 Leased Telephone Circuits.- 4.2.4 Fibre Optic Communication.- 4.2.4.1 Optical Fibres.- 4.2.4.2 Numerical Aperture.- 4.2.4.3 Techniques of Installing Fibre Optic Cable.- 4.2.5 Satellite Communication.- 4.3 Practices in Some Countries.- 4.4 Role of Communications in Load Dispatch Centres.- 4.4.1 Teleprinting.- 4.4.2 Telesignalling and Remote Control.- 4.4.3 Telemetering.- 4.5 Telemetering Systems.- 4.5.1 Analog Telemetering.- 4.5.1.1 Continuous Telemetering.- 4.5.1.2 Selective analog.- 4.5.2 Digital Telemetering.- 4.5.2.1 Digital Cyclic Telemetering.- 5. Determination of Operating Reserve.- 5.1 General.- 5.2 Availability of Generating Units.- 5.2.1 Availability of a Single Generating Unit.- 5.2.2 Availability of a Set of Generating Units.- 5.3 Load Uncertainty Distribution.- 5.3.1 Load Forecast Errors.- 5.3.2 Random Fluctuations of Load.- 5.4 Determination of Necessary Reserve.- 5.5 Classification and Assessment of Reserve.- 5.6 Assignment of Reserve to Various Units and Resources.- 5.7 UCPTE Philosophy.- 6. Load-Generation Balance.- 6.1 Introduction.- 6.2 Short-Term Scheduling.- 6.2.1 Thermal Power Systems.- 6.2.1.1 Unit commitment.- 6.2.1.2 System incremental cost grid.- 6.2.1.3 Determination of hydro generation.- 6.2.1.4 Determination of generation-pumping diagrams of pumped storage power stations.- 6.2.1.5 Determination of thermal generation diagrams.- 6.2.1.6 Split saving.- 6.2.2 Hydro Power Systems.- 6.2.2.1 Assigned reservoir generations.- 6.2.2.2 Assigned medium-term water values.- 6.2.3 Hydro-Thermal Power Systems.- 6.2.4 A New Framework of Scheduling Procedures.- 6.2.5 Conclusions.- 6.3 Medium-Long Term Operation Planning Ill.- 6.3.1 Definition of Some Key Concepts.- 6.3.1.1 Value of reliability.- 6.3.1.2 Firm and non-firm energy.- 6.3.1.1 Cost and revenue functions or curves.- 6.3.1.2 Elementary time interval (or time stage) in medium-long term operation planning.- 6.3.1.3 Value of water.- 6.3.2 Operations planning in randomness.- 6.3.2.1 Operation strategy or closed loop.- 6.3.2.2 Operation policy or open loop.- 6.3.2.3 Deterministic computations.- 6.3.2.4 Comparison of closed loop and open loop methodologies.- 6.3.2.5 Conclusion.- 6.3.3 Methodologies in Use in Some Utilities.- 6.3.3.1 Purely hydro (thermal energy generation less than 15% of the load).- 6.3.3.2 Hydro-thermal (hydro and thermal generation not less than 15% each).- 6.3.3.3 Purely thermal (thermal generation higher than 85.- 6.3.4 Conclusions.- 7. Load Management and Methods of Meeting Peak Demand.- 7.1 General.- 7.2 Flattening of Load Curve.- 7.2.1 Differentiation of Tariffs.- 7.2.2 Ripple Control.- 7.2.3 Under — Voltage Operation.- 7.3 Characteristics of Loads.- 7.4 Measures For Load Management.- 7.5 State-Of -The-Art in the USA.- 7.6 Swedish Project to Optimise Energy Consumption Pattern.- 7.7 Methods of Meeting Peak Demand.- 7.8 Pumped Storage Plant.- 7.8.1 Advantages and Storage Cycles.- 7.8.1.1 Daily Storage Cycle.- 7.8.1.2 Weekly Storage Cycle.- 7.8.1.3 Seasonal Storage Cycle.- 7.8.2 Types of Pumped Storage Equipment.- 8. Security and Reliability of Energy Control Systems.- 8.1 Introduction.- 8.2 Organisation.- 8.2.1 Structure of the ECS.- 8.2.2 Role of Man.- 8.3 Administration.- 8.3.1 Formulation of Orders and Instructions.- 8.3.1.1 The Operational or decision sub-system.- 8.3.1.2 The Information sub-system.- 8.3.1.3 The Executive sub-system.- 8.3.2 Data Base.- 8.3.3 Quality of Documentation.- 8.4 Equipment.- 8.4.1 Role and Principal Components of Equipment.- 8.4.2 The Information System.- 8.4.3 The Decision System (Fig. 8.1).- 8.4.4 The Executive System (Fig. 8.1).- 8.4.4.1 Permanent Automatic Control.- 8.4.4.2 Power System Protective Arrangements.- 8.4.4.3 Operating and Switching remote control equipment.- 8.4.5 Conceptual Criteria For ECS.- 8.4.5.1 Reliability and security.- 8.4.5.2 Response time.- 8.4.5.3 Expandability and Adaptability of the ECS.- 8.4.6 Main Phases of Implementation of An ECS.- 8.4.6.1 User’s specifications.- 8.4.6.2 Development of software.- 8.4.6.3 Auxiliary equipments.- 8.4.6.4 Premises and buildings.- 8.5 Conclusions.- 9. Inter-System Exchanges, Tariffs and Billing.- 9.1 General Principles of Power Exchanges.- 9.1.1 Programming.- 9.1.2 Frontier Point.- 9.1.3 Inadvertent Exchange.- 9.1.4 Billing.- 9.1.5 Bonus or Penalty Factors for Regulation.- 9.1.6 Modification of the Programmes During Operation.- 9.1.7 Control of Exchanges.- 9.1.8 Tariff for Inadvertent Exchanges.- 9.2 Power Exchanges in the UCPTE Countries.- 9.2.1 Pattern of Exchanges.- 9.2.1.1 Energy exchanges and Accounting.- 9.3 Power Pooling and Interchanges in the Usa.- 9.3.1 Operating Hierarchy.- 9.3.2 Typical Interchange Transactions.- 9.3.2.1 Central dispatch.- 9.3.2.2 Sequential dispatch.- 9.3.2.3 Broker dispatch.- 9.3.3 Scheduling, Billing and Accounting.- 9.3.3.1 Scheduling.- 9.3.3.2 Pricing.- 9.3.3.3 Billing for interchange transactions.- 9.3.3.4 Accounting Practice.- 9.3.3.5 Wheeling of power.- 9.4 Banking Transactions and Barter Deal.- 9.4.1 Banking Transactions.- 9.4.1.1 Accounting of the banked energy.- 9.4.1.2 Tariff For Banked Energy.- 9.4.2 Barter Deals.- 9.5 New Organisational Structures.- 9.5.1 Structural Organisation of the Functions of the Electricity Supply Industry.- 9.5.2 Ancillary Services.- 9.5.3 Third Party Access.- 9.5.4 Security of Interconnection.- 9.5.5 Marketing of Electrical Energy.- 9.5.6 Current Status of Application of New Structures and Functions.- Appendix 1: Present Practices in Load Forecasting.- 1. Introduction.- 2. Time Spans.- 3. General Characteristics.- 4. Objectives of Load Forecasting.- 5. Parameters Influencing Load Forecasts.- 5.1 Main Parameters.- 5.2 Meteorological Factors.- 5.3 Special Events.- 6. Methods.- 6.1 Load Forecasting in Practice.- 7. Data and Hardware.- 7.1 Characteristics of the data.- 7.2 Maintenance and Collection of Data.- 7.3 Period considered.- 7.4 Computational Means.- 8. Medium-Long Term.- 9. Short-Term.- 10. Very Short-Term.- 11. Related Issues.- 11.1 Share of load forecast among load buses.- 11.2 MV Ar Demand.- 11.3 Monitoring the Errors.- 12. User’s Opinion.- 13. Conclusions and Recommendations.- Appendix 2: (Reference Chapter 6 — Load-Generation Balance).- Appendix A.- 1. Partitioning of Time in the Scheduling Problems.- 2. Simplifications.- 3. Categorisation of Generation, Load and Power Exchanges.- 4. Constraints.- 5. Criteria of Optimisation.- 5.1 First case: no hydro storage (or “purely thermal”).- 5.2 Second case: no thermal generation (or “purely hydro”).- 5.3 Third case: hydro-thermal power system.- 5.4 Fourth case: no market opportunity.- 5.5 Fifth case: purely hydro, no opportunity exchanges, no secondary load.- 6. Value of Water.- 6.1 Medium term water value.- 6.2 Short-term water value.- 7. Cost Function and Revenue Function.- 7.1 Thermal generation plus opportunity import (cost).- 7.2 Secondary load plus opportunity export (revenue).- 7.3 Combining the two functions.- Appendix B.- Appendix C.- Appendix D.- Appendix E.