Table Of Content

G U I D E L I N E S F O R D E S I G N O F SMALL HYDROPOWER PLANTS Editor Helena RAMOS TECHNICAL CARD Copyright c 2000. Published in 2000 through WREAN (Western Regional Energy Agency & Network) and DED (Department of Economic Development), Belfast, North Ireland. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means except under terms of the Copyright, Designs and Patents Act 1988 without the permission in writing of the publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system for exclusive use by the purchaser of the publication. Title: Guideline for Design of SMALL HYDROPOWER PLANTS Helena Ramos (Chapters: 1, 2, 3, 5, 6, 7 and 9) A. Betâmio de Almeida (Chapters 1, 2, 3, 5, 7, 9 and reviser) M. Manuela Portela (Chapters: 4 and 10) H. Pires de Almeida (Chapter 8) A. Carvalho Quintela (Foreword and reviser) Legal deposit: July 1999. Contents production: Helena Ramos. Cover production - Designer: Joana Cruz. This book has the support of CEHIDRO, WREAN and DED. Typeset in 11/14 pt Times New Roman MS Word 97. FOREWORD The book Guidelines for design of SMALL HYDROPOWER PLANTS comprises the following ten chapters covering the main subjects connected with the design of such plants: 1 – Hydroenergy. 2 – General types of small hydropower plants. 3 – Hydropower and water uses. 4 – Hydrology. 5 – Hydraulic design of small power plants. 6 – Small hydraulic turbines. 7 – Hydraulic transients and dynamic effects. 8 – Electrical equipment. 9 – Environment. 10 – Economic analysis. The first three chapters contain an introduction to the problems involved in the subject under consideration. Chapter 4 deals with hydrologic studies for small hydroelectric schemes with a run-of-the-river exploitation in order to define the design discharges of water conveyance systems and of hydraulic turbines, and power productions. The proposed methodologies may overcome the non-existence of basic flow information at the river section of the scheme intakes. Chapter 5 contains relevant information about the hydraulic design of intakes, bottom outlets, hydraulic conveyance systems (including canals and penstocks) and powerhouses. The object of Chapter 6 is to characterise the differences among the types of small turbines and their behaviour, as well as turbines application ranges and to estimate main dimensions of the turbines. Chapter 7 is the longest one (it fulfils with chapters 5 and 6 half of the book) and presents the main problems concerning hydraulic transients and dynamic effects. Chapter 8 deals with synchronous and asynchronous generators, electrical facilities and control systems. Environment impact assessment is the object of chapter 9. Chapter 10, after considering capital costs, annual operations costs and benefits, presents an economic analysis according to two different concepts and defines economic indexes. It includes an application example of economic analysis. The chapters authors are as following: • Helena Ramos - author of chapters 1, 2, 3, 5, 9 (being second author A. Betâmio de Almeida), and 6, and second author of chapter 7 (being first author A. Betâmio de Almeida). • A. Betâmio de Almeida - author of chapter 7 (being second co-author Helena Ramos) and second author of chapters 1, 2, 3, 5 and 9 (being Helena Ramos the first author). • M. Manuela Portela - author of chapters 4 and 10. • Pires de Almeida. - author of chapter 8. Each author has a good professional experience as consulting engineer in the field of his participation in this book. The first three mentioned authors also have a significant teaching and research experience in such field. The very special background of Prof. A. Betâmio de Almeida must be emphasised. The book identifies the more important subjects of interest for the design of small hydropower plants, which are treated under a rigorous, synthetic and understandable way. The text is completed by appropriated illustrations. Thus, I think that the book will be a very useful tool for those who have a participation in one or more of the multi-disciplinary aspects involved in the design of small power plants and a favourable acceptance will be expected. António de Carvalho Quintela ACKNOWLEDGEMENTS This book is the result of the applied experience in several small hydropower base and final type projects, since I joined the HIDRO4 (now a part of SOMAGUE Engineering Group). A research program in this domain was developed, since the eighties, at Instituto Superior Técnico (IST) of Technical University of Lisbon, and was the basis of my PhD. The book also benefited from the contribution and support from different parts that I would like to acknowledge hereafter. Firstly, I would like to give special thanks to my adviser Professor A. Betâmio de Almeida (Full Professor of IST and an expert in hydraulic transients), whose enthusiasm and scientific revision contributed substantially with their suggestions. Moreover, the colleague Prof. M. Manuela Portela for chapters 4 and 9 and Eng. H. Pires de Almeida, Manager of ENERSIS a mini-hydro power company, with his contribution for chapter 7, are greatly appreciated. I also want to express my gratitude to Professor A. Carvalho Quintela (Full Professor of IST and a very experienced designer of hydroelectric schemes) for taking the time out to do relevant remarks to the original and to write the foreword of this book. Special thanks go to Dr. Robert Gibson, manager from WREAN (Western Regional Energy Agency and Network, North Ireland) and Dr. Lawrence Foy from DED (Department of Economic Development – Energy Division) through their invitation, confidence and interest always proved along the development of this book. I am thankful for the co-operation of several companies, such as ALSTHOM, BOUVIER, CEHIDRO, DED - Energy Division, DUMONT, ENERSIS, EDP, HIDRO4/SOMAGUE, HIDROCENTRAIS REUNIDAS, LNEC, NEYRPIC, VOITH and WREAN, which allowed to support the publishing of this document including some knowledge, photos, project elements and data information. Helena Ramos PhD in Hydraulic/Civil Engineering I S T - Technical University of Lisbon [email protected] CONTENT 1- HYDROENERGY 1 1.1- Renewable energy concept 1 1.2- Hydroelectricity: energy conversion and hydropower principles 3 1.3- Environmental considerations 7 2- GENERAL TYPES OF SMALL HYDROPOWER SCHEMES 9 2.1- Classification of hydropower plants 9 2.2- Hydropower schemes 10 2.3- Site location 13 3- HYDROPOWER AND WATER USES 15 3.1- Power generation and different sector-users 15 3.2- The benefit of small hydropower plants 19 4- HYDROLOGY 21 4.1- Introduction. Scope of the studies 21 4.2- Basic data required for the hydrologic study 22 4.3- Mean annual And mean daily flow series 25 4.3.1- Introduction 25 4.3.2- Annual precipitation and annual flow. Mean daily flow series 26 4.3.3- Mean annual flow duration curve 31 4.4- Energy Evaluation 34 5- HYDRAULIC DESIGN OF SMALL POWER PLANTS 39 5.1- Introduction 39 5.2- Layout schemes 40 5.2.1- Intakes 40 5.2.1.2- Minimum submergence 40 5.2.1.3- Bottom intake 44 5.2.2- Protection rack 48 5.2.3- Sedimentation or desilting basin 51 5.2.4- Weir 54 5.3- Sluice bottom outlet 57 5.4- Conveyance system 58 5.4.1- General layout 58 5.4.2- Head losses and net head 60 5.4.3- Canals 66 5.4.3.1- Uniform and steady state hydraulic regimes 67 5.4.3.2- Boundary conditions 69 5.4.3.3- Forebays 69 5.4.4- General remarks about mixed circuit 71 5.4.5- Penstocks 72 5.5- Powerhouses 75 5.6- Analysis of hydropower schemes 78 6- SMALL HYDRAULIC TURBINES 79 6.1- Types of turbines 79 6.2- Turbine similarity laws and specific speed (N) 84 s 6.3- Turbine efficiency 89