INTEGRATION OF DISTRIBUTED GENERATION IN THE POWER SYSTEM

Transcription

1 INTEGRATION OF DISTRIBUTED GENERATION IN THE POWER SYSTEM

2 IEEE Press 445 Hoes Lane Piscataway, NJ IEEE Press Editorial Board Lajos Hanzo, Editor in Chief R. Abhari M. El-Hawary O. P. Malik J. Anderson B-M. Haemmerli S. Nahavandi G. W. Arnold M. Lanzerotti T. Samad F. Canavero D. Jacobson G. Zobrist Kenneth Moore, Director of IEEE Book and Information Services (BIS) Technical Reviewer Dr. Bimal K. Bose, Life Fellow, IEEE Condra Chair of Excellence/Emeritus in Power Electronics Department of Electrical Engineering and Computer Science University of Tennessee Knoxville, TN USA A complete list of titles in the IEEE Press Series on Power Engineering appears at the end of this book.

3 INTEGRATION OF DISTRIBUTED GENERATION IN THE POWER SYSTEM MATH BOLLEN and FAINAN HASSAN

4 Copyright 2011 by Institute of Electrical and Electronics Engineers. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) , or on the web at Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) , fax (201) , or online at Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) , outside the United States at (317) or fax (317) Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at Library of Congress Cataloging-in-Publication Data: Bollen, Math H. J., Integration of distributed generation in the power system / Math H. Bollen and Fainan Hassan p. cm. (IEEE press series on power engineering) Includes bibliographical references. ISBN (hardback) 1. Distributed generation of electric power. I. Title. TK1006.B dc obook ISBN: epdf ISBN: epub ISBN: Printed in Singapore

5 CONTENTS PREFACE ACKNOWLEDGMENTS xi xiii CHAPTER 1 INTRODUCTION 1 CHAPTER 2 SOURCES OF ENERGY Wind Power Status Properties Variations in Wind Speed Variations in Production Capacity The Weibull Distribution of Wind Speed Power Distribution as a Function of the Wind Speed Distribution of the Power Production Expected Energy Production Solar Power Status Properties Space Requirements Photovoltaics Location of the Sun in the Sky Cloud Coverage Seasonal Variations in Production Capacity Fast Variations with Time Combined Heat-and-Power Status Options for Space Heating Properties Variation in Production with Time Correlation Between CHP and Consumption Hydropower Properties of Large Hydro Properties of Small Hydro Variation with Time Tidal Power Wave Power Geothermal Power Thermal Power Plants 68 v

6 vi CONTENTS 2.9 Interface with the Grid Direct Machine Coupling with the Grid Full Power Electronics Coupling with the Grid Partial Power Electronics Coupling to the Grid Distributed Power Electronics Interface Impact of the Type of Interface on the Power System Local Control of Distributed Generation 81 CHAPTER 3 POWER SYSTEM PERFORMANCE Impact of Distributed Generation on the Power System Changes Taking Place Impact of the Changes How Severe Is This? Aims of the Power System Hosting Capacity Approach Power Quality Voltage Quality Current Quality Multiple Generator Tripping Voltage Quality and Design of Distributed Generation Normal Operation; Variations Normal Events Abnormal Events Hosting Capacity Approach for Events Increasing the Hosting Capacity 100 CHAPTER 4 OVERLOADING AND LOSSES Impact of Distributed Generation Overloading: Radial Distribution Networks Active Power Flow Only Active and Reactive Power Flow Case Study 1: Constant Production Case Study 2: Wind Power Case Study 3: Wind Power with Induction Generators Case Study 4: Solar Power with a Hotel Minimum Consumption Overloading: Redundancy and Meshed Operation Redundancy in Distribution Networks Meshed Operation Redundancy in Meshed Networks Losses Case Study 1: Constant Production Case Study 2: Wind Power Increasing the Hosting Capacity Increasing the Loadability 126

7 CONTENTS vii Building New Connections Intertrip Schemes Advanced Protection Schemes Energy Management Systems Power Electronics Approach Demand Control Risk-Based Approaches Prioritizing Renewable Energy Dynamic Loadability 139 CHAPTER 5 VOLTAGE MAGNITUDE VARIATIONS Impact of Distributed Generation Voltage Margin and Hosting Capacity Voltage Control in Distribution Systems Voltage Rise Owing to Distributed Generation Hosting Capacity Induction Generators Measurements to Determine the Hosting Capacity Estimating the Hosting Capacity Without Measurements Choosing the Overvoltage Limit Sharing the Hosting Capacity Design of Distribution Feeders Basic Design Rules Terminology An Individual Generator Along a Medium-Voltage Feeder Low-Voltage Feeders Series and Shunt Compensation A Numerical Approach to Voltage Variations Example for Two-stage Boosting General Expressions for Two-Stage Boosting Single-Stage Boosting Microgeneration Tap Changers with Line-Drop Compensation Transformer with One Single Feeder Adding a Generator Calculating the Hosting Capacity Multiple Feeders from the Same Transformer Probabilistic Methods for Design of Distribution Feeders Need for Probabilistic Methods The System Studied Probability Density and Distribution Functions Distributions of Functions of Random Variables Mean and Standard Deviation Normal Distributions Stochastic Calculations Using Measurements Generation with Constant Production Adding Wind Power 191

8 viii CONTENTS 5.7 Statistical Approach to Hosting Capacity Increasing the Hosting Capacity New or Stronger Feeders Alternative Methods for Voltage Control Accurate Measurement of the Voltage Magnitude Variations Allowing Higher Overvoltages Risk-Based Approach to Overvoltages Overvoltage Protection Overvoltage Curtailment Dynamic Voltage Control Compensating the Generator s Voltage Variations Distributed Generation with Voltage Control Coordinated Voltage Control Increasing the Minimum Load 221 CHAPTER 6 POWER QUALITY DISTURBANCES Impact of Distributed Generation Fast Voltage Fluctuations Fast Fluctuations in Wind Power Fast Fluctuations in Solar Power Rapid Voltage Changes Very Short Variations Spread of Voltage Fluctuations Voltage Unbalance Weaker Transmission System Stronger Distribution System Large Single-Phase Generators Many Single-Phase Generators Low-Frequency Harmonics Wind Power: Induction Generators Generators with Power Electronics Interfaces Synchronous Generators Measurement Example Harmonic Resonances Weaker Transmission Grid Stronger Distribution Grid High-Frequency Distortion Emission by Individual Generators Grouping Below and Above 2 khz Limits Below and Above 2 khz Voltage Dips Synchronous Machines: Balanced Dips Synchronous Machines: Unbalanced Dips Induction Generators and Unbalanced Dips Increasing the Hosting Capacity Strengthening the Grid 292

9 CONTENTS ix Emission Limits for Generator Units Emission Limits for Other Customers Higher Disturbance Levels Passive Harmonic Filters Power Electronics Converters Reducing the Number of Dips Broadband and High-Frequency Distortion 298 CHAPTER 7 PROTECTION Impact of Distributed Generation Overcurrent Protection Upstream and Downstream Faults Hosting Capacity Fuse Recloser Coordination Inverse-Time Overcurrent Protection Calculating the Fault Currents Upstream Faults Downstream Faults Induction Generators, Power Electronics, and Motor Load Calculating the Hosting Capacity Busbar Protection Excessive Fault Current Generator Protection General Requirements Insufficient Fault Current Noncontrolled Island Operation Islanding Detection Harmonic Resonance During Island Operation Protection Coordination Increasing the Hosting Capacity Dedicated Feeder Increased Generator Impedance Generator Tripping Time-Current Setting Adding an Additional Circuit Breaker Directional Protection Differential or Distance Protection Advanced Protection Schemes Islanding Protection 365 CHAPTER 8 TRANSMISSION SYSTEM OPERATION Impact of Distributed Generation Fundamentals of Transmission System Operation Operational Reserve and (N 1) Criterion Different Types of Reserve Automatic or Manual Secondary Control 375

10 x CONTENTS 8.3 Frequency Control, Balancing, and Reserves The Need for Reserves Primary Control and Reserves Secondary Control and Reserves Tertiary Control and Reserves Impact of Decay in Production on Reserves Prediction of Production and Consumption Restoration after a Blackout Voltage Stability Short-Term Voltage Stability Long-Term Voltage Stability Kinetic Energy and Inertia Constant Frequency Stability Angular Stability One Area Against the Infinite Grid Impact of Distributed Generation: Before the Fault Impact of Distributed Generation: During the Fault Impact of Distributed Generation: Critical Fault-Clearing Time Impact of Distributed Generation: After the Fault Impact of Distributed Generation: Importing Area Fault Ride-Through Background Historical Cases Immunity Requirements Achieving Fault Ride-Through Storage HVDC and Facts Increasing the Hosting Capacity Alternative Scheduling of Reserves Increasing the Transfer Capacity Large-Scale Energy Storage Distributed Generation as Reserve Consumption as Reserve Requirements on Distributed Generation Reactive Power Control Probabilistic Methods Development of Standard Models for Distributed Generation 464 CHAPTER 9 CONCLUSIONS 465 BIBLIOGRAPHY 471 INDEX 497

11 PREFACE The idea of writing this book first came in February 2008, with its final structure being decided by May 2009 when the main writing work also started. The contents of most chapters were finalized about a year thereafter. In the period of 2.5 years that we worked on this book, there have been a lot of developments in the related area: concerning not only new sources of energy (from biomass to nuclear) but also the power system. For the first time in many years, the power system is on the political agenda, instead of just the electricity production or the electricity market. Two important concepts of this book, the hosting capacity and the use of risk-based methods have within the last few months been propagated in important reports by international organizations. The hosting capacity is proposed as a method for quantifying the performance of future electricity networks by both the European energy regulators 1 and by a group of leading European network operators. 2 The latter also recommends the development of risk-based methods for transmission system operation, whereas ENARD, 3 a government-level cooperation within the IEA, makes the same recommendation for the design of distribution networks. During the last few years, while writing this book, giving presentations about the subject, and listening to other s presentations, we also realized that distributed generation and renewable electricity production are very sensitive areas. It is extremely difficult to keep some middle ground between those in favor and those against the idea. We would, therefore, like to emphasize clearly that this book is not about showing how good or how bad the distributed generation is. This book is about understanding the impact of distributed generation on the power system and about methods for allowing more distributed generation to be integrated into the power system, where the understanding is an essential base. By writing this book, we hope to help removing some of the technical and nontechnical barriers that the power system poses to a wider use of renewable sources of energy. June 2011 Math Bollen and Fainan Hassan 1 European Regulators Group for Electricity and Gas, Position paper on smart grids, June 10, ENTSO-E and EDSO. European electricity grid initiative roadmap and implementation plan, May 25, J. Sinclair. ENARD Annex III: Infrastructure asset management. Phase 1 final report, March xi

12 ACKNOWLEDGMENTS The material presented in this book is obtained from different sources. Most of it is work done by the authors themselves, but with important contributions from others. Although some of the ideas presented in this book are much older, the main philosophical thoughts were triggered when André Even introduced the term hosting capacity in 2004 during one of the first meetings of the EU-DEEP project. Discussions with other project partners helped in further refining the concepts. Important contributions, in different forms, were also made by Johan Lundquist (Götene Elförening), Peter Axelberg, Mats Wahlberg (Skellefteå Kraft Elnät), Waterschap Roer en Overmaas, and Emmanouil Styvaktakis. Also, our colleagues and former colleagues Alstom Grid, Chalmers University of Technology, STRI AB (especially Mats Häger, Carl Öhlén and Yongtao Yang, but also many others), Luleå University of Technology, and the Energy Markets Inspectorate should be mentioned for many interesting discussions, which often triggered new ideas. Of course, we should not forget our families and friends here, having been forced to forget them too often during the past two years. xiii