Reactive Power Compensation E-Book

Wolfgang Hofmann

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 346

Veröffentlichungsjahr: 2012

Beschreibung

The comprehensive resource on reactive power compensation, presenting the design, application and operation of reactive power equipment and installations

The area of reactive power compensation is gaining increasing importance worldwide. If suitably designed, it is capable of improving voltage quality significantly, meaning that losses in equipment and power systems are reduced, the permissible loading of equipment can be increased, and the over-all stability of system operation improved. Ultimately, energy use and CO₂ emisson are reduced.

This unique guide discusses the effects of reactive power on generation, transmission and distribution, and looks at the compensation of existing installations in detail. It outlines methods for determination of reactive power and answers the questions that arise when controlling it, for example, at parallel operation with generators. There is also a chapter devoted to installation, maintenance and disturbances.

Key features include:

• A concise overview as well as deep specific knowledge on the segment power factor regulation and network quality
• Theory of reactive power compensation coupled with typical application examples such as car manufacturing, metal rolling and chemical works
• Chapter summaries with charts explaining how to put the theory into practice
• Coverage on the cost-saving aspects of this technology, including the efficient use of energy and the reduction of CO₂

A practical guide for electrical engineers and technicians in utilities, this is also essential reading for maintenance engineers, designers, electrical contractors, manufacturing companies, and researchers, also those in industry and planning agencies. Insightful and clear, the book will also appeal to senior undergraduate and graduate electrical engineering students and professors.

Leseprobe

Contents

Cover

Title Page

Copyright

Foreword and Acknowledgements

1: Basics of Reactive Power

1.1 Chapter Overview

1.2 Phasors and Vector Diagrams

1.3 Definition of Different Types of Power

1.4 Definition of Power for Non-Sinusoidal Currents and Voltages

1.5 Equivalent Mechanical Model for Inductance

1.6 Equivalent Mechanical Model for Capacitance

1.7 Ohmic and Reactive Current

1.8 Summary

2: Reactive Power Consumers

2.1 Chapter Overview

2.2 Reactive Energy Demand

2.3 Simplified Model: Series Reactive Power Consumer

2.4 Realistic Model: Mixed Parallel and Series Reactive Power

2.5 Reactive Power Demand of Consumers

2.6 Summary

3: Effect of Reactive Power on Electricity Generation, Transmission and Distribution

3.1 Chapter Overview

3.2 Loading of Generators and Equipment

3.3 Power System Losses

3.4 Generators

3.5 Voltage Drop

3.6 Available Power of Transformers

3.7 Summary

4: Reactive Power in Standard Energy Contracts

4.1 Chapter Overview

4.2 Introduction

4.3 Reactive Energy to be Considered in Standardized Contracts of Suppliers

4.4 Importance of Reactive Power in Determining the Costs of Connection

4.5 Summary

5: Methods for the Determination of Reactive Power and Power Factor

5.1 Chapter Overview

5.2 Methods

5.3 Summary

6: Improvement of Power Factor

6.1 Chapter Overview

6.2 Basics of Reactive Power Compensation

6.3 Limitation of Reactive Power without Phase Shifting

6.4 Compensation of Reactive Power by Rotational Phase-Shifting Machines

6.5 Compensation of Reactive Power by Means of Capacitors

6.6 Summary

7: Design, Arrangement and Power of Capacitors

7.1 Chapter Overview

7.2 Basics of Capacitors

7.3 Reactive Power of Capacitors

7.4 Different Technologies in Manufacturing Capacitors

7.5 Arrangements and Reactive Power of Capacitors

7.6 Design of MV Capacitors

7.7 Long-Term Stability and Ageing of Capacitor Installations

7.8 Summary

8: Determination of Required Power of Capacitors

8.1 Chapter Overview

8.2 Basics of Calculation

8.3 Determination of Compensation at New Projected Plants

8.4 Summary

9: Types of Reactive Power Compensation

9.1 Chapter Overview

9.2 Single-Type Compensation

9.3 Bulk-Type Compensation

9.4 Central-Type Compensation

9.5 Mixed Compensation

9.6 Advantages and Disadvantages of Different Types of Compensations

9.7 Summary

10: Compensation of Existing Installations

10.1 Chapter Overview

10.2 Methods of Determining the Reactive Power for Extension

10.3 Calculation of the Extension Unit by Means of Energy Invoices

10.4 Summary

11: Control of Reactive Power

11.1 Chapter Overview

11.2 General

11.3 Control of Reactive Power by Automatic Reactive Power Controllers

11.4 How to Wire a Power Factor Relay

11.5 Reactive Power Control by ‘Mixed Measurement’

11.6 Reactive Power Control with Multiple Feed-ins

11.7 Performances of Automatic Compensation Banks

11.8 Summary

12: Discharging Devices for Power Capacitors

12.1 Chapter Overview

12.2 Basis at LV Applications

12.3 Discharging Devices in MV Capacitors

12.4 Calculation of the Electric Charge to be Stored on an MV Capacitor

12.5 Summary

13: Protection of Capacitors and Compensations

13.1 Chapter Overview

13.2 Protection against Overcurrent and Short Circuit

13.3 Overvoltage Protection

13.4 Protection against Overtemperatures

13.5 Protection against Internal Faults

13.6 Protection by Balance Observation at Single-Phase MV Capacitors

13.7 Summary

14: Switching of Capacitors

14.1 Chapter Overview

14.2 General

14.3 Selection of Switchgear

14.4 Switching by Semiconductors (Thyristor Modules)

14.5 Summary

15: Installation, Disturbances and Maintenance

15.1 Chapter Overview

15.2 Installation of Automatically Controlled Compensation Banks

15.3 Automatic Compensation Banks: Setting into Operation

15.4 Disturbances and How to Solve Them

15.5 Working and Maintenance

15.6 Summary

16: Reactive Power Compensation in Electrical Plants with Generators

16.1 Chapter Overview

16.2 General

16.3 Automatic Control of Reactive Power within Four Quadrants

16.4 Summary

17: Effects of Perturbation Considering Especially the Impact of Harmonics on Power Factor Correction Capacitors

17.1 Chapter Overview

17.2 Perturbations and Improved Power Quality for Business Customers

17.3 Measuring and Analysis [2,3]

17.4 Summary

18: Resonances in Electrical Power Systems

18.1 Chapter Overview

18.2 Parallel Resonance Circuit

18.3 Series Resonance Circuit

18.4 Typical Resonances in Power Systems

18.5 Summary

19: Reactor-Protected Capacitors and Filter Circuits

19.1 Chapter Overview

19.2 Effect of Reactor-Protected Systems and System Configuration

19.3 Notes on the Selection of Reactors [3]

19.4 Influence of the Reactor Rate on the Capacitor's Lifetime [4]

19.5 Filter Effect with Detuned Filters [4]

19.6 Filter Circuits

19.7 Neutral Line Harmonic Filtering

19.8 Summary

20: Dynamic Reactive Power Compensation Systems

20.1 Chapter Overview

20.2 Motor Startup Compensation

20.3 Flicker Compensation

20.4 Evaluation of Power Factor Correction Solutions as Seen by the Distribution System Operator (Power Utility) [3,5,7]

20.5 Summary

21: Compensation Effects at Rectifiers

21.1 Chapter Overview

21.2 Compensation Bank at a Six-Pulse Rectifier

21.3 Characteristic Behaviour of Reactive Power Controllers at Rectifiers

21.4 Summary

22: Environmental and Climate Protection Using Capacitors

22.1 Chapter Overview

22.2 PCB-Filled Capacitors

22.3 Climate Change and Energy Efficiency through Power Factor Correction

22.4 Summary

Symbols and Abbreviations

Index

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This edition first published 2012 © 2012, John Wiley & Sons, Ltd

This book includes an authorised translation of selected content from the original German edition published by VDE Verlag GmbH

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Library of Congress Cataloguing-in-Publication Data

Hofmann, Wolfgang, 1945-

[Blindstrom-Kompensation in der Betreibspraxis. English]

Reactive power compensation : a practical guide / Wolfgang Hofmann, Jurgen Schlabbach, Wolfgang Just.

p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-97718-7 (alk. paper)

1. Capacitors. 2. Reactance (Electricity) 3. Electric capacity. 4. Electric action of points. I. Schlabbach, J. (Jürgen) II. Just, Wolfgang. III. Title.

TK2805.H6413 2012

621.3815–dc23

2011042394

Print ISBN: 9780470977187

A catalogue record for this book is available from the British Library.

Foreword and Acknowledgements

The book gives a general overview and also specific deep knowledge about the segment “compensation of reactive power”. Network quality, power losses, energy saving and reduction of CO2 are discussed within 22 chapters forming a technical “dictionary”. It is written to be accessible for all specialists; including engineers, electricians and students. The purpose of this book is to extend the knowledge in this specified field. This “technical guide” answers a lot of questions arising in controlling reactive power e.g. at parallel operation with generators.

This book is based on a book in German published by the VDE Verlag GmbH (Berlin and Offenbach) in the year 2003. Some chapters were revised and adapted or entirely rewritten to conform to new technological developments and changing standards. The chapters have been primarily revised by:

Jürgen Schlabbach – Chapters 1 incl. 4; 18 and 22

Wolfgang Hofmann – Chapters 5 incl. 16 and 21

Wolfgang Just – Chapters 17, 19 and 20

The authors would like to thank all the companies that have contributed pictures and information for the update of this book.We would like to express a special word of thanks to Mr. M. Kreienberg of VDE publishers who supported the idea for this book in English. His assistance in the creation of the drawings was very helpful. Special thanks are also due to the staff of John Wiley & Sons for their help and cooperation during the preparation of this book. We would also like to remember the late Miss Nicky Skinner, who looked after our book project at the very beginning.

Our thanks are also extended to our families for their patience during the uncounted hours of writing the book.

Our sincere thanks are directed to the following companies who supplied us with documentations, photos, (circuit-) diagrams and technical support for the total of 22 chapters of our book:

Maschinenfabrik Reinhausen GmbH

KoCos Power Grid Services GmbH

Janitza Electronics GmbH

Hans von Mangold GmbH & Co. KG

Electronicon Kondensatoren GmbH

System Electric Power Quality GmbH

Frako Kondensatoren und Anlagenbau GmbH

Condensator Dominit GmbH

IESA; Brazil

Boddingtons Power Controls LTD, U.K.

General Motors do Brasil

Schneider Electric; Brazil

Dr. Rolf Richter, ZVEI e.V., Frankfurt, Germany

Florence Richter (freelance translator, BA in English and Ancient Greek) in translating Chapters 17, 19 and 20

Munich, Dorsten, Bielefeld; Germany; 2011-10-20

In case the reader may have any questions, please contact the authors: [email protected]@[email protected]

1

Basics of Reactive Power

1.1 Chapter Overview

This chapter deals with the definitions and fundamentals of active, reactive and apparent power in the case of sinusoidal and non-sinusoidal current and voltage. The differences between power factor, taking account of only the fundamental frequency components, and distortion factor, taking account of higher frequency components as well, are explained. Equivalent mechanical models are presented to explain the behaviour of inductance and capacitance and the generation of reactive power.

1.2 Phasors and Vector Diagrams

Motors, discharge lamps, transformers, generators with lagging power factor, as well as cables and overhead lines with high current loading, need reactive power to build up the magnetic field, sometimes called the consumption of reactive or inductive power. Other equipment and consumers, such as rectifiers with capacitive smoothing, compact fluorescent lamps, capacitors, generators with leading power factor and overhead transmission lines and cables in no-load or low-load operation, need reactive power to build up the electric field, an effect called the generation of reactive or capacitive power. In contrast to active power, reactive power is not converted into heat, light or torque, but fluctuates between the source (e.g. capacitor) and the drain (e.g. motor). Compared with pure active power, the current is increased as the active current and the reactive current are added to the apparent current according to their amount and phase angle.

When dealing with AC and three-phase systems, it should be noted that currents and voltages are generally not in phase. The phase position depends on the amount of inductance, capacitance and ohmic resistance at the impedance.

The time course, for example of a current or voltage, varies in accordance with

(1.1a)

(1.1b)

as can be shown in a line diagram, see . In the case of sinusoidal variables, these can be shown at the complex numerical level by rotating pointers, which rotate in a mathematically positive sense (counter-clockwise) with angular velocity as follows: