High Voltage Engineering

Farouk A.M. Rizk, Giao N. Trinh

• Publisher: CRC Press
• Year: 2018
• Print ISBN: 9781466513761
• eBook ISBN: 9781351832335
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Inspired by a new revival of worldwide interest in extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission, High Voltage Engineering merges the latest research with the extensive experience of the best in the field to deliver a comprehensive treatment of electrical insulation systems for the next generation of utility engineers and electric power professionals. The book offers extensive coverage of the physical basis of high-voltage engineering, from insulation stress and strength to lightning attachment and protection and beyond.

Presenting information critical to the design, selection, testing, maintenance, and operation of a myriad of high-voltage power equipment, this must-have text:

• Discusses power system overvoltages, electric field calculation, and statistical analysis of ionization and breakdown phenomena essential for proper planning and interpretation of high-voltage tests
• Considers the breakdown of gases (SF6), liquids (insulating oil), solids, and composite materials, as well as the breakdown characteristics of long air gaps
• Describes insulation systems currently used in high-voltage engineering, including air insulation and insulators in overhead power transmission lines, gas-insulated substation (GIS) and cables, oil-paper insulation in power transformers, paper-oil insulation in high-voltage cables, and polymer insulation in cables
• Examines contemporary practices in insulation coordination in association with the International Electrotechnical Commission (IEC) definition and the latest standards
• Explores high-voltage testing and measuring techniques, from generation of test voltages to digital measuring methods

With an emphasis on handling practical situations encountered in the operation of high-voltage power equipment, High Voltage Engineering provides readers with a detailed, real-world understanding of electrical insulation systems, including the various factors affecting—and the actual means of evaluating—insulation performance and their application in the establishment of technical specifications.

1

Power System Overvoltages

1.1 Introduction

In general, a power system consists of a large number of generators, step-up or step-down transformers, and domestic, commercial, and industrial electrical loads, connected together through a network of overhead transmission lines and underground cables. Connection and disconnection of power system elements are undertaken by power circuit breakers and associated disconnecting switches under both normal operating conditions or to protect the system from occasional faults.

The voltage level of transmission trunk lines is economically determined by the magnitude of transmitted power and by the length of the transmission line. For a given power level, a higher voltage reduces the line current and accordingly the power losses. In ac systems, the steady-state stability limit is proportional to the square of the voltage. A higher voltage, therefore, improves the power system stability margin. On the other hand, system insulation has to be able to sustain the voltage in order to maintain reliability. Obviously, more insulation is more costly, which results in the concept of most economic voltage. Furthermore, for a given conductor size, higher voltage leads to more corona losses and more adverse environmental impact as expressed by radio interference (RI) and audible noise, leading to the necessity of optimizing the conductor bundle and the concept of most economic current density.

Power system insulation is exposed not only to normal stresses associated with steady-state conditions but also to external and internal overvoltages and to occasionally serious deterioration of the insulation due to adverse atmospheric conditions. External overvoltages occur when a transmission line is struck by lightning, while internal overvoltages are generated due to faults and switching operations. For high-voltage transmission systems, only direct strikes to ground wires, towers, or power conductors are important, while at lower voltages, induced lightning overvoltages become also important. Overvoltages generated due to switching operations and ground faults include temporary o...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Acknowledgments
• Authors
• 1. Power System Overvoltages
• 2. Electrostatic Field Calculation
• 3. Application of Statistical Analysis in High Voltage Engineering
• 4. Electrical Breakdown in Gases
• 5. Breakdown Characteristics of Long Air Gaps
• 6. Electric Breakdown in Liquids
• 7. Electric Breakdown in Solid and Composite Materials
• 8. Selection of Overhead Transmission Line Conductors
• 9. Lightning Incidence and Lightning Protection
• 10. High-Voltage Insulators
• 11. High-Voltage (Underground) Cables
• 12. Power Transformers
• 13. Insulation Coordination
• 14. High-Voltage Testing and Measuring Techniques
• Index