Extruded Cables for High-Voltage Direct-Current Transmission E-Book

Giovanni Mazzanti

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: IEEE Press Series on Power Engineering
• Sprache: Englisch

Seitenzahl: 647

Veröffentlichungsjahr: 2013

Beschreibung

The only book on the market that provides current, necessary, and comprehensive technical knowledge of extruded cables and high-voltage direct-current transmission This is the first book to fully address the technical aspects of high-voltage direct-current (HVDC) link projects with extruded cables. It covers design and engineering techniques for cable lines, insulation materials, and accessories, as well as cable performance and life span and reliability issues. Beginning with a discussion on the fundamentals of HVDC cable transmission theory, Extruded Cables for High-Voltage Direct-Current Transmission: Advances in Research and Development covers: * Both the cable and the accessories (joints and terminations), each of which affects cable line performance * The basic designs of HVDC cables--including a comparison of mass insulated non-draining cables with extruded HVDC cables * The theoretical elements on which the design of HVDC cables is based--highlighting the differences between HVAC and HVDC cables * Space charge-related problems that have a critical impact on extruded insulation for HVDC application * Recent advances in extruded compounds for HVDC cables such as additives and nano-fillers * The improved design of extruded HVDC cable systems--with emphasis on design aspects relevant to accessories * Cable line reliability problems and the impact on cable system design Including more than 200 illustrations, Extruded Cables for High-Voltage Direct-Current Transmission fills a gap in the field, providing power cable engineers with complete, up-to-date guidance on HVDC cable lines with extruded insulation.

Leseprobe

Contents

Cover

Series Page

Title Page

Copyright

Foreword

Acknowledgments

List of Symbols and Acronyms

Introduction

Chapter 1: Introduction

References

Chapter 2: Fundamentals of HVDC Cable Transmission

2.1 Historical Evolution of HVDC Power Transmission

2.2 Economic Comparison between HVAC and HVDC Transmission Systems

2.3 Configurations and Operating Modes of HVDC Transmission Systems

2.4 CSC and VSC Converters

2.5 Cables for HVDC Transmission

References

Chapter 3: Main Principles of HVDC Extruded Cable Design

3.1 Differences between HVAC and HVDC Extruded Cables

3.2 Transient DC Field Distribution

3.3 Influence of the Environment Temperature on the Steady Field of an HVDC Extruded Cable

3.4 Impulses Superimposed onto a DC Voltage

3.5 Statistical Approach to Impulse Voltage Test Levels for HVDC Cables

3.6 Modification of the Stress Distribution by Trapped Space Charge Effects

3.7 Dielectrics for HVDC Extruded Cables

3.8 Morphology of Polyethylene and Its Influence on Electrical Properties

References

Chapter 4: Space Charge in HVDC Extruded Insulation: Storage, Effects, and Measurement Methods

4.1 Space Charge in HVDC Cable Insulation

4.2 Charge Injection and Transport in Insulating Polymers

4.3 Space-Charge Accumulation

4.4 Review of Space-Charge Measurement Methods for HVDC Extruded Insulation

4.5 Up-to-Date Developments of the Best Techniques for Measuring Space Charges

4.6 Final Comparison between the Best Space-Charge Measurement Methods for Power Cables: PEA versus TSM

References

Chapter 5: Improved Design of HVDC Extruded Cable Systems

5.1 R&D Trends in Improving Extruded Polymeric Insulation for HVDC Cables

5.2 Use of AC LDPE, XLPE, or HDPE Cable Compounds for HVDC Applications without Any Modifications

5.3 Stress Inversion-Free or -Limited DC Cable

5.4 Suppression of Space Charge in the Polymer

5.5 Further Requirements for the Improvement of HVDC Extruded Cable Design

5.6 Improved Design of HVDC Extruded Cables

5.7 Improved Design of Accessories for HVDC Extruded Cable Systems

5.8 Improved Cable System Design

5.9 Testing of HVDC Extruded Cable Systems

References

Chapter 6: Life Modeling of HVDC Extruded Cable Insulation

6.1 Fundamentals of Life Modeling and Reliability Estimates of Power Cables

6.2 Space-Charge-Based Life Models for Extruded HVDC Cables

6.3 From Space Charges to Partial Discharges: Life Model Based on Damage Growth from Microvoids

6.4 Space Charge: Cause or Effect of Aging?

References

Chapter 7: Main Realizations of HVDC Extruded Cable Systems in the World

7.1 Overview

7.2 Extruded Systems in Service

References

Index

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IEEE Press Editorial Board 2013

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Copyright © 2013 by The Institute of Electrical and Electronics Engineers, Inc.

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Published simultaneously in Canada.

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Library of Congress Cataloging-in-Publication Data:

Mazzanti, Giovanni, 1962-

Extruded cable for high voltage direct current transmission : advances in research and development / Giovanni Mazzanti, Massimo Marzinotto.

pages cm

Includes bibliographical references.

ISBN 978-1-118-09666-6 (cloth)

1. Electric power distribution–Direct current. 2. Electric power distribution–High tension. 3. Electric cables. 4. Electric cable sheathing. I. Marzinotto, Massimo, 1975- II. Title.

TK3111.M39 2013

333.793′2–dc23

2012042392

Foreword

High-voltage direct-current (HVDC) transmission is not new. Edison, a pioneer of all things DC, constructed a 45-km link connecting Miesbach and Munich in 1882 using rotating DC machines at each end. A few HVDC links were constructed in the next 50 or so years, partly following the advent of mercury arc rectifiers; but they largely fell out of favor when the advantages of alternating-current (AC) transmission were realized. AC benefits from using transformers—which are straightforward to manufacture and efficient to use—to step-up and step-down voltages. The AC induction machine, while perhaps not so efficient, is rugged and low in maintenance and cheap to make. The twentieth century saw the development of electrical distribution systems connecting consumers and generators within cities and of transmission systems using national grids.

However, in the infamous words of Bob Dylan, “The times they are a-changin'.” Grids are no longer national—the countries of Europe are connected, the states of the United States are connected, and the provinces of China are connected. We are moving to pan-continental grids covering typically 10 million square kilometers and distances of 4000 km or more. Yet our grids have transmission lines that rarely stretch more than a 100 km at a time. This is partly because of the capacitive and inductive limitations of AC transmission and partly because they were never designed for anything else. Our networks are getting congested: On occasions more than 90% of the power transmitted in Belgium is not being used by the Belgians. It is simply transmitted across the country connecting the neighboring countries on either side.

Our current electrical transmission networks are analogous to road networks with no motorways (or interstate highways.) We need electrical superhighways to transmit huge amounts of power long distances across continents. This is partly to connect consumers with sustainable sources of power. For example, the windy wet northern climate of Europe offers wind and hydroelectric generation, while the sunnier climes in the south offer photovoltaic and solar thermal possibilities. Generally, humans shy away from the really wet, windy, and hot climates and so long-distance transmission is often necessary to connect such regions of generation to centers of population. Nuclear power stations are often distant from cities, perhaps for reasons of safety. Similarly, the Three Gorges Dam situated near Yichang in China, which the guidebook states generates the equivalent of 10 nuclear power stations, needs to transmit vast amounts of power to Shanghai, 1000 km to the east. East–west pan-continental electrical superhighways facilitate “power lopping.” The 4000-km width of a typical continent is about 10% of the circumference of the world and therefore corresponds to a 2.5-h time difference. Those in the east will be switching on their kettles for breakfast while those in the west are still asleep. Those in the west will be cooking their dinners while those in the east are doing the washing up. Transmitting power east and west can therefore reduce a region's peak power generation requirements. Electrical grids are necessary for the 21st century, and the lower electrical losses and reduced space demands afforded by HVDC transmission systems when used over longer distances are likely to afford the appropriate solution technologies.

Because our existing grids are connected together, we have also seen other problems. Cascading failures, where a failure on one network brings down a connected network leading to a domino effect bringing down successive networks, are difficult to control on massively interconnected AC network systems. Fifty-five million people were left without electricity in the northeastern and midwestern U.S. states and Ontario in August 2003 after such a cascading failure. HVDC back-to-back links between AC grids are likely to be efficacious firewalls preventing such wide-scale failures. Deregulation and privatization, smart grids, and indeed some renewable energy sources such as wind have led and will lead to faster changing demands and supplies requiring systems that can react more quickly. Without the problems of phase synchronization, this is more straightforward to achieve with DC than AC systems.

Of course, the move to HVDC brings with it some technical challenges. Since the 1980s, we have seen the successful wide-scale introduction of extruded coaxial high-voltage AC power cables with polymeric insulation (typically cross-linked polyethylene). These cables can support voltages of 10s to 100s of kilovolts and carry currents of 1000s of amps. Three-phase systems may transport all the energy from a large power station. Early problems with reliability have been overcome through the use of triple extrusion techniques for extruding “semicon” polymeric conductors contemporaneously with the insulation, and through the use of super-clean materials, the exclusion of water, and great care to avoid contaminants and voids in the insulation and protrusions from the electrodes. Due to geometrical effects, the electric field in the insulation is slightly higher nearer the center conductor, but not greatly so. Although the temperature near the center conductor can be significantly higher than that at the outer electrode, this makes little difference to the electric field in AC cables, as the field is controlled by the permittivity, which itself is not strongly dependent on temperature. The electric field is therefore defined everywhere by the applied voltage and the cable geometry; this is important since high electric fields are likely to lead to more rapid degradation and possibly to breakdown. Under DC conditions this is not necessarily the case. The electric field may be controlled by the conductivity, which is highly dependent on temperature, and may be enhanced by electrical charge (“space charge”) that can accumulate in the insulation. An in-depth understanding of these phenomena is therefore required to manufacture and operate HVDC systems using extruded power cables.

With the resurgence of interest in using HVDC transmission systems, this book is therefore timely and will, I am sure, be of great interest to manufacturers and operators of such systems. Although not all the problems are solved, especially with the quest to operate at higher voltage and powers, the book will help to guide the way forward. It will also provide an excellent introduction for researchers in this area and those developing new cable materials and systems.

I was therefore very pleased to be asked by Giovanni Mazzanti at the 2012 IEEE CEIDP to write this foreword and I would like to congratulate the authors on a job well done!

John Fothergill

City University London

Acknowledgments

First of all we sincerely thank some persons belonging to the IEEE DEIS (Dielectrics and Electrical Insulation Society) who—as reference members for both their role and their outstanding scientific contribution to this society—have encouraged our idea of writing this book since the beginning and have fostered its publication by Wiley-IEEE Press, namely Simon Rowland, Reuben Hackam, and Len Dissado. Moreover, we thank John Fothergill very much for its excellent foreword to this book.

We also thank all the peer referees that have reviewed our sample paragraphs before the acceptance of the manuscript for publication by Wiley-IEEE Press, as well as after the completion of the manuscript. They have spent a lot of time and attention in reading carefully this lengthy stuff and have provided precious suggestions for improving the quality of the book. Moreover, we are grateful to the Wiley-IEEE Press staff for the patience and care devoted to the editing and printing of our manuscript.

We greatly acknowledge the following people (in alphabetical order), who have provided valuable contributions to this book in terms of photos and design schemes from the main manufacturers of HVDC extruded cable systems in the world:

Shinya Asai (J-Power System Corporation)

Fabio Bocchi (Prysmian Powerlink)

Fabien Charles (General Cable - Silec)

Marc Jeroense (ABB High Voltage Cables)

Bengt Jonnerfeld (former ABB High Voltage Cables)

Cornelia Kohn (ABB High Voltage Cables)

Mohammed Mammeri (General Cable - Silec)

Marco Marelli (Prysmian Powerlink)

Josep Martinez (General Cable - Silec)

Pierre Mirebeau (Nexans)

Giorgio Mussi (Hitachi Cable Europe)

Akitoshi Watanabe (Viscas)

We also acknowledge Stefania De Felice for the valuable help with the graphics for the cover of the book.

Finally, we acknowledge our families for the patience and support they gave us during the lengthy writing of this book.