Advanced Load Dispatch for Power Systems

The series Advances in Industrial Control aims to report and encourage technology transfer in control engineering. The rapid development of control technology impacts all areas of the control discipline. New theory, new controllers, actuators, sensors, new industrial processes, computer methods, new applications, new philosophies ... , new challenges. Much of this development work resides in industrial reports, feasibility study papers and the reports of advanced collaborative projects. The series offers an opportunity for researchers to present an extended exposition of such new work in all aspects of industrial control for wider and rapid dissemination. In Europe, and soon in the United States, power system deregulation is becoming widespread. This involves the privatisation of former public power utilities and the creation of power markets. The United Kingdom has recently undergone this transformation and the countries of the European Union are being encouraged to follow this deregulation policy. This volume Advanced Load Dispatch for Power Systems and its companion volume Control of Modem Integrated Power Systems both by Professor E. Mariani and Professor S.S. Murthy are therefore very timely additions to the power system literature and to the Advances in Industrial Control series.

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.