Computer-Aided Power Systems Analysis

George Kusic

• Publisher: CRC Press
• Year: 2018
• Print ISBN: 9781420061062
• eBook ISBN: 9781351834964
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Computer applications yield more insight into system behavior than is possible by using hand calculations on system elements. Computer-Aided Power Systems Analysis: Second Edition is a state-of-the-art presentation of basic principles and software for power systems in steady-state operation.

Originally published in 1985, this revised edition explores power systems from the point of view of the central control facility. It covers the elements of transmission networks, bus reference frame, network fault and contingency calculations, power flow on transmission networks, generator base power setting, and state estimation from on-line measurements.

The author develops methods used for full-scale networks. In the process of coding and execution, the user learns how the methods apply to actual networks, develops an understanding of the algorithms, and becomes familiar with the process of varying the parameters of the program.

Intended for users with a background that includes AC circuit theory, some basic control theory, and a first course in electronic machinery, this book contains material based upon the author's experience both in the field and in the classroom, as well as many Institute of Electrical and Electronic Engineers (IEEE) publications. His mathematical approach and complete explanations allow readers to develop a solid foundation in power systems analysis.

This second edition includes downloadable resources with stand-alone software to perform computations of all principles covered in the chapters. Executable programs include 0,1,2 conversions, double-hung shielded transmission line parameters, zero and positive bus impedance computations for unbalanced faults, power flow, unit commitment, and state estimation.

1

Central Operation and Control of Power Systems

1.1 General

Electric power systems came into service in the 1880s and since that time have grown enormously in size and complexity. Their power generation, transmission, and distribution methods and equipment have consistently improved in performance and reliability. The power industry provided the first large-scale application of nuclear energy, was among the first to use analog controls for turbine generators, and introduced the use of on-line digital control computers. These advances were often mandatory because of the enormous growth in megawatt requirements of the power systems.

As power systems increased in size, so did the number of lines, substations, transformers, switchgear, and so on. Their operation and interactions became more complex; therefore, it became essential to monitor this information simultaneously for the total system at a focal point, which is now called an energy control center. A fundamental design feature of energy control centers is that they increase system reliability and economic feasibility, but system operation is possible without the energy control center. This is essentially a fail-safe type of operation. In practice, all communication links between equipment and the control center could be interrupted and the electric service maintained. For example, most systems maintain local as opposed to centralized control of protective switchgear that must function within several cycles of the 60 Hz line upon detection of an overload. The same switchgear may be operated on a slower basis from the energy control center. As another example, a generating plant in the system remains synchronized to the transmission network and maintains its existing power output level even without signals received from the control center.

An energy control center fulfills the function of coordinating the response of the system elements in both normal operations and emergency conditions. The burden of repetitious control in normal situations is delegated to the digital computer, and selective monitoring is performed by human operators. Essentially, the digital computer is used to process the incoming stream of data, detect abnormalities, and then alarm the human operator via lights, buzzers, or graphical interface (i.e., computer screens) presentations. Many lower-level or less serious cases of exceeding normal limits are routinely handled by the digital computer. For example, if an increase in generation must be allocated to all machines of the system and a generator is already at its high power limit, its share would be distributed among the remaining units. A more serious abnormality detected by the digital computer may cause suspension of normal control functions.

In extreme emergencies, such as loss of a major generator or excess power demands by a neighboring utility on the tie lines, many alarms would be detected and the system would enter an emergency state. The operator may be flooded with information and no diagnostics. The present state of the art is that the digital computer programs perform the first attempts at diagnosing the source of several simultaneous alarms, but remedial or corrective actions remain the responsibility of the human operator, usually called a dispatcher.

1.2 Control Center of a Power System

Figure 1.1 is a photograph of the interior of an energy control ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• Preface
• 1 Central Operation and Control of Power Systems
• 2 Elements of Transmission Networks
• 3 Bus Reference Frame
• 4 Network Fault and Contingency Calculations
• 5 Power Flow on Transmission Networks
• 6 Generator Base Power Setting
• 7 State Estimation from Real-Time Measurements
• Appendix A Conductor Resistance and Rating
• Index