Small Hydroelectric Engineering Practice is a comprehensive reference book covering all aspects of identifying, building, and operating hydroelectric schemes between 500 kW and 50 MW. In this range of outputs there are many options for all aspects of the scheme and it is very important that the best options are chosen. As small hydroelectric schemes are usually built against a limited budget it is extremely important that the concept design is optimum and every component is designed to maximise the benefi t and minimise the cost. As operating costs are often a high proportion of the income it is very important to make sure that everything is designed to be simple, reliable and long lasting. The book is based on the experience gained over 45 years on the overall and detailed design, construction and commissioning of more than 30 small hydropower schemes. It includes contributions from experts in the field of intakes, water diversion structures, geology, canals, painting and other aspects of hydropower development. It is intensely practical with many drawings and photographs of schemes designed and commissioned by Leyland Consultants and others.There are also sections on preparing specifi cations, tender assessment and operation and maintenance. The book includes a CD with spreadsheet programs for analysing aspects of small hydropower development and many arrangement drawings and detail designs for gates, penstocks, electrical systems and control systems. Typical specifi cations for generating plant are also included. The spreadsheets will be useful during the feasibility stage and the drawings will enable designers to scale the designs as needed for their own projects. Consultants, developers, designers, builders and operators of small hydroelectric schemes will find this book invaluable.
Preface xiii
Acknowledgements xv
About the author xvii
List of figures xix
List of abbreviations xxiii
1 Introduction 1 (4)
1.1 Key features of small hydro schemes 3 (2)
2 Scheme identification 5 (6)
2.1 Preliminary study 5 (1)
2.1.1 Cost estimates 6 (1)
2.2 Feasibility study 6 (5)
2.2.1 Site survey 6 (1)
2.2.2 Hydrology 7 (1)
2.2.3 Geology 8 (1)
2.2.4 Environmental assessment 8 (1)
2.2.5 Preliminary estimates 9 (1)
2.2.6 Preliminary report 10 (1)
3 Refining the design 11 (14)
3.1 Hydrology 11 (1)
3.2 Geology 12 (1)
3.3 Headworks 12 (4)
3.3.1 Spillway options 13 (1)
3.3.2 Intakes 13 (1)
3.3.3 Canal design 14 (2)
3.4 Penstocks and intakes 16 (1)
3.4.1 Penstock intakes 16 (1)
3.4.2 Steal penstocks 16 (1)
3.4.3 Wood stave penstocks 16 (1)
3.4.4 Plastic and GRP penstocks 17 (1)
3.5 Turbine selection 17 (3)
3.5.1 Low head turbines 17 (2)
3.5.2 Medium head turbines 19 (1)
3.5.3 High head turbines 19 (1)
3.6 Powerhouse arrangement 20 (1)
3.7 Useful spreadsheets 20 (1)
3.8 Preliminary financial analysis 21 (1)
3.9 Outside financing 21 (4)
3.9.1 "Bankable" feasibility study 22 (1)
3.9.2 Economic and financial analysis 22 (3)
4 Detailed design of intake works, canals and 25 (48)
penstocks
4.1 Environmental factors 25 (2)
4.2 Final optimisation 27 (2)
4.2.1 Technical optimisation 28 (1)
4.2.2 "Alab" computer program 28 (1)
4.2.3 "Hydrohelp" computer program 29 (1)
4.3 Intakes at low weirs 29 (6)
4.3.1 Coanda screen 29 (3)
4.3.2 Streambed intake 32 (1)
4.3.3 Bypassing 32 (1)
4.3.4 Settling basin 33 (2)
4.4 Conventional intakes 35 (9)
4.4.1 Screen cleaners 37 (1)
4.4.2 Intake gates 38 (4)
4.4.3 Penstock filling 42 (1)
4.4.4 Additional information on intakes 43 (1)
4.5 Spillways 44 (8)
4.5.1 Flap (fish belly) gates 44 (1)
4.5.2 Obermeyer gates 45 (1)
4.5.3 Radial gates 46 (6)
4.6 Bypass gates 52 (1)
4.7 Stoplogs and bulkheads 53 (1)
4.8 Canal regulating gates 54 (2)
4.9 Additional information on gates 56 (1)
4.10 Canals 56 (3)
4.10.1 Controlling leakage 58 (1)
4.10.2 Small unlined canals 58 (1)
4.10.3 Canal linings 58 (1)
4.10.4 Under drainage 59 (1)
4.10.5 Further information 59 (1)
4.11 Penstocks and water hammer 59 (13)
4.11.1 Water hammer 60 (2)
4.11.2 Steel penstocks 62 (6)
4.11.3 Glass reinforced plastic (GRP) 68 (3)
penstocks
4.11.4 HDPE and PVC penstocks 71 (1)
4.12 Surface treatment and painting of 72 (1)
steelwork
5 Turbine selection 73 (52)
5.1 Introduction 73 (1)
5.2 Number of turbines 73 (1)
5.3 Particulate erosion 74 (1)
5.4 Kaplan and Francis turbines 75 (12)
5.4.1 Guide vanes 78 (3)
5.4.2 Guide vane actuation 81 (2)
5.4.3 Cavitation 83 (3)
5.4.4 Hydraulic stability and rough running 86 (1)
5.5 Low head turbines 87 (11)
5.5.1 Dimensions of Kaplan turbines 88 (1)
5.5.2 Vertical Kaplan turbines 88 (3)
5.5.3 Bulb turbines 91 (1)
5.5.4 Pit turbines 92 (1)
5.5.5 Matrix turbines 93 (2)
5.5.6 Axial Kaplan turbines 95 (1)
5.5.7 Open flume Kaplan turbines 95 (3)
5.5.8 Very low head turbines 98 (1)
5.5.9 Stoplogs and emergency isolation 98 (1)
5.6 Medium head turbines 98 (17)
5.6.1 Dimensions of Francis turbines 99 (3)
5.6.2 Air admission 102 (1)
5.6.3 Vertical Francis turbines 103 (1)
5.6.4 Horizontal Francis turbines 104 (3)
5.6.5 Twin horizontal Francis turbines 107 (4)
5.6.6 Inlet valves 111 (2)
5.6.7 Relief valves 113 (1)
5.6.8 Bypass valves 114 (1)
5.7 Pelton turbines 115 (6)
5.7.1 Dimensions of Pelton turbines 115 (1)
5.7.2 Pelton turbine arrangement 115 (2)
5.7.3 Pelton turbine runners 117 (2)
5.7.4 Pelton turbine options 119 (2)
5.7.5 Turgo turbines 121 (1)
5.8 Governing systems 121 (4)
6 Generators 125 (16)
6.1 Overspeed 125 (1)
6.2 Synchronous generators 126 (15)
6.2.1 Stators 127 (2)
6.2.2 Corona 129 (1)
6.2.3 Excitation systems 129 (1)
6.2.4 Neutral earthing 130 (1)
6.2.5 Lightning protection 131 (1)
6.2.6 Generator cooling 132 (3)
6.2.7 Overspeed testing 135 (1)
6.2.8 Increasing generator inertia 136 (1)
6.2.9 Bearings 136 (2)
6.2.10 PTFE bearings 138 (1)
6.2.11 Bearing cooling and monitoring 138 (1)
6.2.12 Induction generators 139 (2)
7 Electrical systems 141 (12)
7.1 Single line diagram 141 (4)
7.1.1 Transformers 142 (1)
7.1.2 Station earthing 143 (1)
7.1.3 Transmission 144 (1)
7.2 Control 145 (5)
7.2.1 Control philosophy 145 (1)
7.2.2 Communications 146 (1)
7.2.3 Programmable Logic Controllers 147 (1)
7.2.4 Programming instructions 148 (2)
7.3 Protection and instrumentation 150 (2)
7.4 Synchronising 152 (1)
8 Auxiliary plant 153 (4)
8.1 Auxiliary AC power supplies 153 (1)
8.2 DC power supplies 153 (1)
8.3 Water piping 154 (1)
8.4 Sump pumping 155 (2)
9 Specifications and contracts 157 (14)
9.1 Conditions of contract 158 (2)
9.1.1 General Conditions of Contract 158 (2)
9.2 Specifications for major generating plant 160 (7)
9.2.1 Turbine specifications 161 (3)
9.2.2 Governing systems 164 (1)
9.2.3 Inlet and bypass valves 165 (1)
9.2.4 Generator specifications 165 (1)
9.2.5 Tender schedules 166 (1)
9.2.6 Sample specifications 166 (1)
9.3 Specifications for other mechanical and 167 (1)
electrical plant
9.4 Surface preparation and painting 167 (2)
9.4.1 Background 167 (1)
9.4.2 Specification requirements 168 (1)
9.5 Assessment of tenders 169 (2)
10 Powerhouse layout and design 171 (4)
11 Construction and commissioning 175 (4)
11.1 Project construction 175 (1)
11.2 Commissioning 176 (3)
12 Operation 179 (4)
12.1 Generating plant 179 (2)
12.2 Civil works 181 (1)
12.3 Safety and environmental requirements 181 (2)
13 Lessons from failures 183 (8)
13.1 Civil engineering failures 183 (3)
13.1.1 Ruahihi canal collapse 183 (1)
13.1.2 Wheao canal and head-pond breach 184 (1)
13.1.3 Aniwhenua canal leak 185 (1)
13.1.4 Lessons from civil engineering 186 (1)
failures
13.2 Generating plant failures 186 (5)
13.2.1 Station in the Pacific, 1990 186 (2)
13.2.2 Mangahao power station 188 (1)
13.2.3 Tuai power station 189 (1)
13.2.4 Duffers power station 190 (1)
14 Appendix 1: Useful spreadsheets and computer 191 (6)
programs
14.1 Hydro scheme data and cost estimates 191 (1)
14.2 Intake screen head losses 192 (1)
14.3 Turbine dimensions 192 (1)
14.4 Cost estimates for turbines and 193 (2)
generators
14.5 Financial analysis 195 (2)
15 Appendix 2: Financial and economic 197 (4)
considerations
15.1 Objectives of financial analysis 197 (1)
15.2 Objectives of economic analysis 197 (1)
15.3 Approach and methodology 198 (3)
15.3.1 Financial evaluation 198 (1)
15.3.2 Levelized Cost of Electricity 199 (1)
15.3.3 Overview of economic cost benefit 200 (1)
analysis
16 Appendix 3: Environmental issues with two 201 (4)
hydropower schemes
16.1 Aniwhenua 201 (1)
16.2 Onekaka 202 (3)
17 Appendix 4: Making the most of hydro 205 (14)
specifications
17.1 Introduction 205 (1)
17.2 The tenderer/contractor - an interesting 206 (1)
species
17.3 Specifications 207 (5)
17.3.1 Performance specifications 207 (1)
17.3.2 Performance specification vs 207 (1)
prescriptive specification
17.3.3 Getting the "A" team 208 (1)
17.3.4 Life cycle cost analysis 209 (1)
17.3.5 Is the specification tough enough? 209 (1)
17.3.6 Interfacing with existing equipment 209 (1)
17.3.7 Warranties 210 (1)
17.3.8 Drawings 210 (1)
17.3.9 Innovation vs conservatism 210 (1)
17.3.10 Contract inspection 210 (1)
17.3.11 Works acceptance vs Site acceptance 211 (1)
17.3.12 Project schedule 211 (1)
17.4 Looking beyond the specification 212 (4)
17.4.1 Educating our masters 212 (1)
17.4.2 Legal advice 212 (1)
17.4.3 Commercial advice and instruction 213 (1)
17.4.4 General Conditions of Contract 213 (1)
17.4.5 Special Conditions of Contract 213 (1)
17.4.6 Instructions to tenderers 214 (1)
17.4.7 Partnering 215 (1)
17.4.8 Tender evaluation 215 (1)
17.5 Conclusion 216 (3)
References 219 (2)
Subject index 221 (4)
Contents of CD 225
新书报道