Mathematical modelling and solution on digital computers is the only practical approach to systems analysis and planning studies for a modern day power system with its large size, complex and integrated nature. The stage has, therefore, been reached where an undergraduate must be trained in the latest techniques of analysis of large-scale power systems. A similar need also exists in the industry where a practising power system engineer is constantly faced with the challenge of the rapidly advancing field. This book has been designed to fulfil this need by inte-grating the basic principles of power system analysis illustrated through the simplest system structure with analysis techniques for practical size systems. In this book large-scale system analysis follows as a natural extension of the basic principles. The form and level of some of the well-known techniques are presented in such a manner that undergraduates can easily grasp and appreciate them.

The book is designed for a two-semester course at the undergraduate level. With a judicious choice of advanced topics, some institutions may also find it useful for a first course for postgraduates.

The reader is expected to have a prior grounding in circuit theory and electrical machines. He should also have been exposed to Laplace transform, linear differential equations, optimisation techniques and a first course in control theory. Matrix analysis is applied throughout the book. However, a knowledge of simple matrix operations would suffice and these are summarised in an appendix for quick reference.

The digital computer being an indispensable tool for power system analysis, computational algorithms for various system studies such as load flow, fault level analysis, stability, etc. have been included at appropriate places in the book. It is suggested that where computer facilities exist, students should be encour-aged to build computer programs for these studies using the algorithms provided. Further, the students can be asked to pool the various programs for more advanced and sophisticated stud-ies, e.g. optimal scheduling. An important novel feature of the book is the inclusion of the latest and practically useful topics like unit commitment, generation reliability, optimal thermal scheduling, optimal hydro-thermal scheduling and decoupled load flow in a text which is primarily meant for undergraduates.

The introductory chapter contains a discussion on various methods of electrical energy generation and their techno-economic compar-ison. A glimpse is given into the future of electrical energy. The reader is also exposed to the Indian power scenario with facts and figures.

Chapters 2 and 3 give the transmission line parameters and these are included for the sake of completness of the text. Chapter 4 on the representation of power system components gives the steady state models of the synchronous machine and the circuit models of composite power systems along with the per unit method.

Chapter 5 deals with the performance of transmission lines. The load flow problem is introduced right at this stage through the simple two-bus system and basic concepts of watt and var control are illustrated. A brief treatment of circle diagrams is included as this forms an excellent teaching air for putting across the concept of load flow and line compensation. ABCD constants are generally well covered in the circuit theory course and are, therefore, relegated to an appendix.

Chapter 6 gives power network modelling and load flow analysis, while Chapter 7 gives optimal system operation with both approxi-mate and rigorous treatment.

Chapter 8 deals with load frequency control wherein both conven-tional and modern control approaches have been adopted for analy-sis and design. Voltage control is briefly discussed.

Chapters 9–11 discuss fault studies (abnormal system operation). The synchronous machine model for transient studies is heuristi-cally introduced to the reader.

Chapter 12 emphasises the concepts of various types of stability in a power system. In particular the concepts of transient sta-bility is well illustrated through the equal area criterion. The classical numerical solution technique of the swing equation as well as the algorithm for large system stability are advanced.

Every concept and technique presented is well supported through examples employing mainly a two-bus structure while sometimes three- and four-bus illustrations wherever necessary have also been used. A large number of unsolved problems with their answers are included at the end of each chapter. These have been so selected that apart from providing a drill they help the reader develop a deeper insight and illustrate some points beyond what is directly covered by the text.

The internal organisation of various chapters is flexible and permits the teacher to adapt them to the particular needs of the class and curriculum. If desired, some of the advanced level topics could be bypassed without loss of continuity. The style of writing is specially adapted to self-study. Exploiting this fact a teacher will have enough time at his disposal to extend the coverage of this book to suit his particular syllabus and to include tutorial work on the numerous examples suggested in the text.

The authors are indebted to their colleagues at the Birla Insti-tute of Technology and Science, Pilani and the Indian Institute of Technology, Delhi for the encouragement and various useful suggestions they received from them while writing this book. They are grateful to the authorities of the Birla Institute of Tech-nology and Science, Pilani and the Indian Institute of Technolo-gy, Delhi for providing facilities necessary for writing the book. The authors welcome any constructive criticism of the book and will be grateful for any appraisal by the readers.

I J NAGRATH
D P KOTHARI