The need to improve electric supply systems is stipulated by development of industry, transport, civil engineering and the agroindustrial complex. These enterprises are the main consumers of electric power in complex infrastructure of industrial centers. They consume electric power with different frequencies, voltages and currents. They are also characterized by high density of electric loads. Their electric supply systems have multilevel stages of power distribution; large-scale load centers with different transformations of electromagnetic energy parameters, power consumers of various types; power sources of power system, local thermal power stations, synchronous compensators, sources of reactive power, in emergencies - motors went to generating mode; significant degree of branching; negative feedback of electric technological processes and powerful consumers on the system operation in emergencies.

Construction and maintenance of the electric power supply systems involves considerable material resources. That is why it is very important to improve their efficiency and reliability in different operating conditions, including malfunctions and post-emergency modes. This stipulates high requirements to these systems, to their operating modes and electric power quality. These requirements can be assessed on the basis of transient investigation.

Methods of investigation and evaluations of transients is the important field of research and development. Their aim is development of new level electric power supply systems, sustaining their modes stability with the required levels of economy, electric power quality, reliability, and maintenance safety. Use of simulation methods and computing facilities greatly contributes to solving tasks arising at analysis and evaluations of transients. They allow to choose the most appropriate circuit designs and electric characteristics of the system components, and also to forecast their economical and technical performances not only in normal, but also in transient modes.

The problems are analyzed with use of language structures, which will assist to students’ self-instruction, their comprehension of teaching material and mastering in modem research and evaluation principles in English.

The book consists of introduction and two parts. In the first part electromagnetic transients caused by shorts, longitudinal and lateral asymmetry are considered. Chapter 1 covers starting positions, basic assumptions and principles of equivalent representation for analysis of transients in electric power supply system. Equivalents of electric supply system elements and its mode parameters are the basis for construction of equivalent circuits (chapter 1), which are used for analytical (chapter 2) and practical (chapter 3) calculations of three-phase short circuits. Various types of lateral (chapter 5) and longitudinal (chapter 6) asymmetry, their combinations and complex faults are analyzed using the method of symmetrical components. Influence of technology and electric consumers operating modes on supply networks is illustrated in chapter 7. Measures of short circuit currents and power limitation are considered in chapter 8. Also conditions for their optimization are formulated.

The part two is devoted to electromechanical transients and to combined influence of the electromagnetic and electromechanical transients on power supply system operation stability. Investigation of the electromechanical transients unlike the electromagnetic processes is based on use of the power supply system characteristics and its components mathematical models (chapter 9). In chapters 10 and 11 techniques of analysis the power supply system important properties such as static and dynamic operation stability with reference to its part and to external power supply networks are described. Influence of large (chapter 12) and small (chapter 13) disturbances on load nodes of internal power supply networks are discussed. Possible measures providing the power supply system operation stability are resulted (chapter 14). In the chapter 15 methods of monitoring and diagnostics of the electric power system emergency operation modes are given.

There are control questions and topics for essays at the end of the chapters for better comprehension of the given material. They will help students' self-dependent activities in learning the discipline.

Authors will gratefully accept remarks and readers’ opinion, which will assist to further improvement of this text-book.

Acknowledgments

Authors wish to thank O. Balakhontsev, V. Gavrilyuk and L. Tokar, who have translated the book into English; Professors O. Ivanov and S. Kostritskaya for editing the English version of the textbook; assisting lecturers A. Siomin and S. Dybrin who have prepared the computer version of the edition.