Good and Bad of Mini Hydro Power Vol.1
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Transcript of Good and Bad of Mini Hydro Power Vol.1
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GOOD & BADof
Mini Hydro Power
Volume 1 Site Identification Civil Works Electro-Mechanical
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Klaus Jordewith the resources of Entec AG
Ekart Hartmann, Heinz Unger
Edited by
Roman RitterGTZ
ASEAN-German Mini Hydro Project(AGMHP)
GOOD & BADof
Mini Hydro Power
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GOOD & BAD of Mini Hydro Power
Imprint
GOOD & BADof Mini Hydro Power
Authors: Klaus Jorde with the resources of Entec AG;Ekart Hartmann, Heinz Unger
Editing:Roman Ritter, GTZ
Photos, drawings and graphics provided by: The Indonesian-German Mini Hydro Power Project (MHPP)
Published by: The ASEAN Centre for Energy (ACE)under the direction of its Executive Director, Nguyen Manh Hung,supported by the ASEAN-German Mini Hydro Project (AGMHP)
Jl. HR. Rasuna Said, Blok X-2, Kav 7-8, KuninganJakarta 12950, IndonesiaPhone : +62 (0)21 527 8027Fax : +62 (0)21 529 63820Websites : http://www.aseanenergy.org http://agmhp.aseanenergy.org http://www.gtz.de/energy
First published by ACE in June 2009
Photographs, drawings and any other graphical elements are intellectual copyright protected and therefore must not be extracted separately from this publication. However, complete chapters of this book may be translated into other languages and thereby be reproduced for training purposes, provided the publisher is informed of these purposes and proper acknowledgements are made.
Disclaimer:The publication has been prepared to illustrate good & bad practice examples in micro and mini hydro power planning, implementation, operation & management. While all reasonable care has been taken in the preparation of this publication, the authors, editors, ACE, AGMHP, Entec AG, GTZ, MHPP, PT Entec Indonesia and any other individuals and parties involved accept no responsibility for damage, injury or any other undesirable events resulting from its application or interpretation.The ultimate responsibility for quality, reliability and safety remains with designers, suppliers, installation teams and operating agencies. It is strongly recommended that any design, construction, electrical or mechanical installation, operation, maintenance and repair works are carried out and/or supervised and checked by qualified technicians and engineers only.
ISBN : 978-979-8978-26-5/978-979-8978-27-2
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GOOD & BAD of Mini Hydro Power
Table of Contents
Volume 1
1 SITE IDENTIFICATION 11.1 General 21.2 Run of River Hydro Power Station 21.3 Feasibility 41.3.1 Site Identification and Flow Measurement 41.3.2 Rough Calculation of Possible Hydro and Electrical Power 61.3.3 Estimate Electrical Load 71.3.4 How to Measure the River/Stream Flow? 71.3.5 Discharge Measurements and Flow Duration Curve 141.3.6 Head Measurement 151.3.7 General Project Data 241.3.8 Synergies, Ownership and Management 261.3.9 Energy Supply and Demand 271.3.10 Consultants 29
2 CIVIL WORKS 312.1 Construction Basics 322.2 Individual Components 442.2.1 Weir and Intake 442.2.2 Sand Trap - Settling Basin 532.2.3 Headrace Channel 572.2.4 Forebay 702.2.5 Trash Rack 752.2.6 Spillway 812.2.7 Penstock and Support 852.2.8 Power House and Tailrace 97
3 ELECTRO-MECHANICAL EQUIPMENT 1053.1 Basics 1063.2 Individual Components 1113.2.1 Turbine 1113.2.2 Main Elements of a Generator 1173.2.3 Panel, Controller and Ballast 1213.2.4 Inside the Power House 1293.2.5 Power House Wiring 1363.2.6 Mechanical Transmission 1433.2.7 Tools and Spare Parts 152
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GOOD & BAD of Mini Hydro Power
Volume 2
4 TRANSMISSION & DISTRIBUTION 1614.1 General Basics 1624.1.1 Basics for Grid Planning, Design & Layout 1624.1.2 Implications of Productive End Use on Network Design 1634.2 Major Components 1644.2.1 Transformer Station 1644.2.2 Distribution Poles and Lines 1684.2.3 Wiring connections 1704.2.4 Maintenance 178
5 HOUSE INSTALLATION 1815.1 General 1825.2 Major Elements 1835.2.1 Service Connection 1845.2.2 Current Limiting Device 1865.2.3 Metering 1885.2.4 House Wiring and Fittings 192
6 MANAGEMENT AND ADMINISTRATION 2016.1 Community Participation and Mobilisation 2026.2 Institutional Setup 2076.3 Capacity Building and Training 2106.4 Tariff Policy 2116.5 Financial Management 2156.6 Monitoring and Documentation 216
7 UTILIZATION OF ENERGY 219
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GOOD & BAD of Mini Hydro Power
Foreword
The urgent call for reducing the carbon footprint of our economies combined with the worlds ever growing demand for scaling-up access to energy is a priority challenge on the global agenda which defines the role for renewables.
Renewable energies offer climate-friendly, low risk technology options for decentralized power generation. In remote areas, utilizing local renewables to support the development of poor rural communities is often more economically viable than transporting diesel fuel or expanding the national electricity grid over long distances. In locations where however the network infrastructure is already in place, harnessing natural resources for feeding power into the central grid also offers an important source of local income that contributes to macroeconomic stability by gaining independence from price-volatile fossil fuels.
In the light of this, the Association of South East Asian Nations (ASEAN) is emphasizing the need to strengthen the development of renewable energies. Promoting mutual cooperation for the transfer of knowledge and skills in order to narrow development gaps among the ASEAN countries, to empower the regions peoples, and ultimately to alleviate poverty is seen as the way forward.
With this publication, GOOD & BAD of Mini Hydro Power, the ASEAN Centre for Energy (ACE) aims to provide valuable lessons from experiences gained in one member country for the dissemination of good practices throughout the whole region. This is intended to support the capacity development of ASEANs human resources in the sustainable planning, design, implementation, management, operation and maintenance of mini hydro power (MHP).
The two underlying principles of this book are: a picture is worth a thousand words and the only real mistake is the one from which we learn nothing. Thus along the sequence from water to wire contrasting pictures of good & bad examples are provided to illustrate what actually defines the difference. Each picture is complemented by short explanations so that the book can serve as a technical training manual that offers direct and easy-to-understand guidance.
Although MHP is a relatively mature and cost-competitive energy technology, a lot of mistakes are still being made which lead to increased maintenance cost, reduced power output, shortened service life or even physical danger. The good news is that in many cases it is only small changes which need to be made doing things the right way often requires no more funds than doing them the wrong way. However, what is definitely required is a proper awareness and expertise among hydro practitioners and their principals for whom, quite literally, knowledge is power.
Nguyen Manh Hung Roman RitterACE, Executive Director GTZ, Principal Advisor AGMHP
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GOOD & BAD of Mini Hydro Power
AcknowledgementsThis book draws on countless photographs and experiences which have been collected in practically applying international MHP know-how for the successful improvement of mini hydro power implementation in Indonesia.
Therefore special thanks go to the Indonesian Directorate General for Electricity and Energy Utilization (DGEEU) and its Mini Hydro Power Project (MHPP) which has been jointly implemented for more than 10 years by DGEEU and GTZ, the German Technical Cooperation Deutsche Gesellschaft fr Technische Zusammenarbeit.
Big thanks also go to the team of authors who made great efforts in bringing together Entecs expertise in MHP development with the didactical concept of using contrasting pictures which require only short explanations to point out the decisive difference.
Last but certainly not least, the ASEAN Centre for Energy (ACE) is highly grateful to the German Federal Ministry for Economic Cooperation and Development (BMZ) for its continuous support of the ASEAN-German Mini Hydro Project (AGMHP) which provided the necessary resources for compiling this publication.
Nguyen Manh HungACE, Executive Director
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GOOD & BAD of Mini Hydro Power
1. Site Identification1. Site Identification
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Site Identification
2 GOOD & BAD of Mini Hydro Power
1.1GENERAL
Mini hydro power stations (MHP) are installations often referred to as generating less than 1,000 kW electrical energy. The hydraulic sources are:
t 3JWFSTBOETUSFBNTt 8BUFSTPVSDFTt 8BUFSTVQQMZNBJOTt 8BTUFXBUFSTZTUFNT
To create electricity in a small hydro power station the following two questions are essential:
t )PXNVDIXBUFSJTBWBJMBCMFUISPVHIPVUUIFZFBSGPSUIFUVSCJOFPX t 8IBUJTUIFQPTTJCMFEJFSFODFJOIFJHIUIFBE
1.2 RUN OF RIVER HYDRO POWER STATION
Flow and head are the most important parameters for the design of a hydro power plant.
Typical example of a diversion type run-of-river hydropower plant
t "SVOPGSJWFSIZESPQPXFSQMBOUJTB.)1XJUIPVUBOZSFTFSWPJSPSTUPSBHFDBQBDJUZt "EJWFSTJPOUZQFIZESPQPXFSQMBOUJTB.)1XIFSFUIFXBUFSJTEJWFSUFEGSPNUIFSJWFSJOUP
a channel and/or penstock system
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Site Identification
3GOOD & BAD of Mini Hydro Power
t *OHFOFSBMUIFSFBSFUXPUZQFTPG.)1SFHBSEJOHHSJEDPOOFDUJPO- Isolated MHP- Grid connected MHP
t *O TPNF BTQFDUT UIF EFTJHO PG BO JTPMBUFE .)1 JT EJFSFOU UIBO UIF POF PG B HSJEconnected. Most components, such as civil works and hydraulic components are the same
t *OTPNFDBTFT.)1BSFCVJMUBTJTPMBUFE.)1BOEMBUFSBSFDPOOFDUFEUPUIFHSJE
Note:
CHOOSING INCORRECT PARAMETERS AND DEVELOPING THEREWITH A NON-OPTIMIZED DESIGN RESULTS IN MASSIVE COST INCREASES OR UNSATISFYING PERFORMANCE!
IT IS THEREFORE STRONGLY RECOMMENDED TO CALL AN EXPERIENCED MHP EXPERT FOR THE DESIGN PHASE!
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Site Identification
4 GOOD & BAD of Mini Hydro Power
1.3 FEASIBILITY
The most important information which must be available is the general location and UPQPHSBQIZPGUIFTJUFUIFPXXIJDIJTBWBJMBCMFJOUIFSJWFSUISPVHIPVUUIFZFBSBOEUIFhead difference which can be utilized. Additionally it is important to know the distance to the potential electricity consumers and/or the closest power line near by.
1.3.1 Site Identification and Flow Measurement
The following information must be gathered:
t 5IFXBUFSPXEVSJOHUIFXIPMFZFBSXJUINBYJNVNBOENJOJNVNPXt 5IF PQUJNBM MBZPVU PG UIF XIPMF TDIFNFXJUI JOUBLF IFBESBDF TBOE USBQ QFOTUPDL
powerhouse and tailrace
t 4J[FBOEMFOHUIPGUSBOTNJTTJPOBOEEJTUSJCVUJPOMJOFGSPNQPXFSIPVTFUPUIFVTFSTPGthe electricity
t "EFNBOEGPSFDBTUGPSIPVTFIPMETTNBMMJOEVTUSJFTBOETPDJBMJOGSBTUSVDUVSFGBDJMJUJFTGPSbe connected in the future
Collect river/stream flow data
'PSIZESPQPXFSEFTJHOJUJTWFSZJNQPSUBOUUPIBWFPXEBUBPWFSBTNBOZZFBSTBTQPTTJCMFUPbe sure how much water (in rainy and dry season) is available to run a turbine. These data give the designer the basic information for the selection of a turbine that works most efficiently.
With this information and the demand of the consumers, the designer can choose the proper turbine and generator as well as he can define size and length of the grid for an isolated MHP.
Hydrographs for a 16 year period
5IFHVSFTIPXTEBJMZPXTNFBTVSFEPWFSBQFSJPEPGZFBST5IJTJTBOJEFBMEBUBTJUVBUJPOIn reality, such good data are often not available.
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Site Identification
5GOOD & BAD of Mini Hydro Power
Flow duration curve
"TPDBMMFEPXEVSBUJPODVSWFJTHFOFSBUFECZTPSUJOHBMMNFBTVSFEPXEBUBTJ[FXJTFBOEprinting them over 100% of the time covered by the measurements. The diagram says for example that during 23% of the time the discharge is higher than 10 m3/s. This curve is the most important information for the design of the hydropower plant. If it is not based on good data everything else becomes equally speculative as well.
*G UIF SFRVJSFE NFBTVSFNFOUT BSF OPU BWBJMBCMF UIFO UIF PX TIPVME CF NFBTVSFE BOErecorded every day during minimum one year in order to get the following curve:
&YBNQMFPGBPXEVSBUJPODVSWFGPSPOFZFBS
5IFPXEVSBUJPODVSWF JTHFOFSBUFEGSPNUIFSJWFSEJTDIBSHFDVSWFCZTPSUJOHBMM UIFWBMVFT#BTFEPOUIFPXEVSBUJPODVSWFUIFEFTJHOFSFWBMVBUFTUIFBWBJMBCMFDBQBDJUZ5IFEJNFOTJPOJOHPGUIFQMBOUEFQFOETPOUIFBWBJMBCMFPXPGXBUFSBOEUIFFTUJNBUFEGVUVSFdemand of the customers. Ideally the MHP should allow covering the demand all around the year. If the demand is higher than the available capacity, alternative energy resources have to be identified and/or energy efficiency measures have to be taken into consideration.
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Site Identification
6 GOOD & BAD of Mini Hydro Power
If you cannot get good measurements over an extended period of time you need the help of an experienced hydrologist for this analysis.
1.3.2 Rough Calculation of Possible Hydro and Electrical Power
By answering the following questions youll find out, if the scheme is worth to go ahead with the planning:
)PXNVDIPXJTBWBJMBCMF .FBTVSFBOEESBXBXBUFSPXDVSWFIZESPHSBQIBTTIPXOBCPWF GPSNJOJNVNPOF ZFBS5BLF UIFNJOJNVN PX GPSZPVSGVSUIFSDPOTJEFSBUJPOT5IJTJTUIFPXPGXBUFSXIJDIyou have available all year round.
2. How much head is available?
Measure the head from the location of the possible forebay
to the place where the turbine is planned to be placed.
8IFOIFBEBOEEJTDIBSHFXBUFSPXJTLOPXOJUJTFBTZUPDBMDVMBUFUIFUIFPSFUJDBMIZESPpower:
P = Power in WattQ = Minimum available flow H = Head, difference in height in meter
This formula shows the hydraulic capacity only and refers to 100% efficiency without losses. Losses in penstock, turbine, gear transmission, generator and electricity transmission reduce the final electrical power. By calculating losses of 20.30%, the final electrical power will approximately be:
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Site Identification
7GOOD & BAD of Mini Hydro Power
EXAMPLE:
-FUTVTFUIFPXEVSBUJPODVSWFGPSPOFZFBSPOPOFPGUIFQSFWJPVTQBHFTBTBOFYBNQMF5IFNJOJNVNUVSCJOFPXXIJDIJTJOEJDBUFEUIFSFJTBSPVOEMT5IJTPXJTFYDFFEFEEBZTQFSZFBSUIFSFNBJOJOHEBZTUIFPXJTTMJHIUMZTNBMMFSTPUIFIZESPQPXFSQMBOUXJMMgenerate less power accordingly. Lets assume that we have a head of 30 m available. In this case the power generation will be:
So this MHP will generate almost 19 kW.
If the designer chooses a larger turbine, lets say with the design charge of 220 l/s, the MHP DPVMEHFOFSBUFBSPVOEL8CVUPOMZGPSBCPVUEBZTFWFSZZFBSEVSJOHIJHIPXT5IFremainder of the year, around 300 days, the MHP would generate much less power, depending on the discharge which is available.
1.3.3 Estimate Electrical Load
Try to estimate the required electrical power supply needed for all households, public infrastructure facilities (e.g. schools, markets, clinics, community buildings, and street lightings), workshops, etc in the electrical system. For each household calculate around 50150 W for lighting, radio, TV, fan, refrigerator, etc.8JUIUIFPXPGUIFBCPWFFYBNQMFBSPVOEIPVTFIPMETDBOCFTVQQMJFEBMMZFBSSPVOEby a possible MHP.
1.3.4 How to Measure the River/Stream Flow
*UTOPUFBTZUPNFBTVSFBOBDDVSBUFPXPGBSJWFSPSTUSFBN5IFPXNFBTVSFNFOUIBTUPCFUBLFOFWFSZEBZEVSJOHPOFGVMMZFBS'PSUIJTUIFJOTUBMMBUJPOhas to be appropriate and robust. Depending on the size of the river or stream there are EJFSFOUNFUIPETUPNFBTVSFUIFPX
t #VDLFU.FUIPEt 'MPBU.FUIPEt $VSSFOU.FUFS.FUIPE7FMPDJUZ"SFB.FUIPET
t 4IBSQ$SFTUFE8FJS.FUIPEt 4BMU$PODFOUSBUJPO.FUIPE
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Site Identification
8 GOOD & BAD of Mini Hydro Power
Bucket Method
'PSTNBMMPXBSPVOEMTPOMZt *GZPVIBWFPOMZBTNBMMPXZPVDBOEPUIFNFBTVSFNFOUTXJUIUIJTNFUIPEt *UTJNQPSUBOUUPUBLFBCJHUBOLBSPVOEMJUFSXJUIESBJOQMVHBUUIFCPUUPNt 5IFPXUPCFNFBTVSFEJTEJWFSUFEJOUPUIFUBOLPGLOPXOWPMVNFt 5IFUJNFJUUBLFTUPMMUIFUBOLNVTUCFSFDPSEFEt #ZEJWJEJOHUIFWPMVNFJO MJUFSPGUIFUBOLCZUIFMMJOHUJNFJOTFDPOETUIFPXJO
liter/seconds can be calculated
Note:
THIS METHOD IS VERY ACCURATE IF YOU ARRIVE TO REALIZE SUCH AN INSTALLATION! BUT USE IT FOR SMALL FLOWS ONLY!
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Site Identification
9GOOD & BAD of Mini Hydro Power
Float Method
'PSPXMT
Profile
Define the cross section area first. Normally its more difficult than in our example (Cross section = H x W). Try to divide the whole cross section into several sections, when the profile is not rectangular, and add the different sections together to define the whole cross section.
Float
For a known length of the stream (L), an average cross section should be available, where a half filled plastic bottle of water has to be timed over a measured length (L = 1020 m). By NVMUJQMZJOHDSPTTTFDUJPOBSFBXJUIBWFSBHFPXWFMPDJUZBOFTUJNBUJPOPGPXSBUFDBOCFmade now. For any case a correction factor of +/- 20% must be applied.
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Site Identification
10 GOOD & BAD of Mini Hydro Power
Current Meter Method (Velocity-Area Methods)
t "UBOZQPJOU JOUIFSJWFS UIFWFMPDJUZ JTEJFSFOUoGBTUFSPOUIFTVSGBDFBOETMPXFSPOUIFCPUUPN5IFWFMPDJUZPGUIFPXDBOCFNFBTVSFEBUEJFSFOUEFQUITBOEBUBOZQPJOUof the rivers cross section by a so called current meter
t 5IF WBMVFT IBWF UP CF BWFSBHFE 5IF WFMPDJUZ NFBTVSFNFOU EBUB BSF UIFO VTFE UPDBMDVMBUFUIFBDUVBMPXCBTFEPOUIFBSFBPGFBDITFHNFOU
t #FGPSF TUBSUJOH UIFWFMPDJUZNFBTVSFNFOUTNBSL UIF DSPTT TFDUJPOXJUI BIPSJ[POUBMMZlaid out piece of steel or timber to get a reference height. Note the location of the cross TFDUJPOPOBNBQBOEBMTPOPUFEBUFBOEUJNFPGUIFPXNFBTVSFNFOU
Note:
THIS METHOD IS SUITABLE FOR FLOW VELOCITIES RANGING FROM 0.2 - 5 m/s AND WHERE YOU CAN SAFELY WADE THE STREAM!
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Site Identification
11GOOD & BAD of Mini Hydro Power
Sharp Crested Weir Method
Why is this a good example?
t 4IBSQDSFTUFEXFJSTXJUIDPOUSPMMFEPXQSPWJEFHPPEPXNFBTVSFNFOUT
But:
t 5IFJOTUBMMBUJPOJTOPUFBTZBOEOFFETBMPUPGTLJMMBOEFYQFSJFODFt 3FGFSFODFUBCMFTIBWFUPJOEJDBUFSFMBUJPOCFUXFFOIFJHIUIBOEPX2t 5IFXFJSPOUIFQJDUVSFJTOPURVJUFSFDUBOHVMBS
Measuring rod
h
L
b
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Site Identification
12 GOOD & BAD of Mini Hydro Power
'PSSFDUBOHVMBSXFJSTXJUICNBOE-JTBQQSPYJNBUFMZoNUIFPXDBOCFSFBEPVUfrom following table:
t "OZNBUFSJBMDBOCFVTFEGPSUIFXFJSCVUUIFOPUDITIPVMEIBWFTIBSQFEHFTNFUBMJTthe best)
t 8FJSTBSFBMXBZTPSJFOUFEBUBSJHIUBOHMFUPUIFTUSFBNPXt *GCJTXJEFSPSOBSSPXFSUIBONZPVDBOTJNQMZNVMUJQMZUIF2WBMVFTJOUIFUBCMFCZ
UIFTBNFSBUJP-FUTTBZGPSBNXJEFXFJSZPVNVMUJQMZUIF2WBMVFTCZBOEGPSBNXJEFXFJSZPVNVMUJQMZUIF2WBMVFTCZ
t " TIBSQ DSFTUFE XFJS JT BMTP B HPPE EFWJDF UP HFOFSBUF B PX EVSBUJPO DVSWF(hydrograph) over a longer period of time, e.g. one year. You only need to install a staff gauge 2-3 m upstream of the weir, read the gauge level every day at the same time, calculate the discharge based on the table above, and write this into a table
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Site Identification
13GOOD & BAD of Mini Hydro Power
Salt Concentration Method
The figure shows intensity of conductivity
t " CVDLFU XJUI TBMU XBUFS PG LOPXO DPODFOUSBUJPO JT QPVSFE JOUP UIF NJEEMF PG UIFTUSFBN5IFTBMUDPODFOUSBUFDMPVEXJMMCFTQSFBECZUIFPXPGUIFSJWFS
t 5IF QSPCF JT JOTFSUFE BU MFBTU UJNFT UIF SJWFS XJEUI EPXOTUSFBN UP NFBTVSF UIFelectric conductivity of the stream / salt concentrate mixture. So if the river is 10 m wide, you should measure at least 200 m downstream
t 5IFTUSFBNPXXJMMCFNFBTVSFEBOEDBMDVMBUFECZUIFDPOEVDUJWJUZNFUFS
Note:
THIS METHOD OF MEASUREMENT CAN ONLY BE USED BY A TRAINED PERSON WITH PROPER EQUIPMENT!
gauging point
Distance: injection to gauging point
point of tracer injection
M=V.C1 tracer cloudA
B
trac
er co
ncen
trat
ion
FAFB
tBtA Time
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Site Identification
14 GOOD & BAD of Mini Hydro Power
1.3.5 Discharge Measurements and Flow Duration Curve
0GDPVSTFJUJTBDPOTJEFSBCMFFPSUUPNFBTVSFUIFPXOPNBUUFSXIJDINFUIPEZPVVTF4PZPVPOMZXBOUUPEPUIJTBGFXUJNFTCVUJUNVTUCFBUEJFSFOUPXTMFUTTBZEVSJOHUIFMPXFTUPXZPVDBOPCTFSWFBOEGVMMSJWFSPXBOEUXPTNBMMFSPXTJOCFUXFFO"UUIFTBNFtime you always measure the stage of the river at the same location and you must install a permanent staff gauge for this purpose. Then you can develop a relationship between the stage and the discharge, based in your measurements. It is a simple curve, shown green in the figure below.
Staff gauge for quick and easy water level reading
The red stars represent the measurements which you have taken. From then on you must only measure the stage, lets say every day at noon, and your curve will tell you what the discharge is at the same time. The two blue arrows indicate how this works. If you do this for POFZFBSZPVIBWFUIFQFSGFDUEBUBGPSBPXEVSBUJPODVSWF
Note:
IF YOU DO NOT UNDERSTAND THIS PROCEDURE YOU MUST HIRE AN EXPERT TO HELP YOU!
Staff
gau
ge (c
m)
Discharge (l/s)
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Site Identification
15GOOD & BAD of Mini Hydro Power
1.3.6 Head Measurement
Head is the difference in height between the water level of the planned forebay and the planned position of the turbine shaft. There are different ways to measure it.
Schematic example of head measurement
turbine
Head
Level of forebay
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Site Identification
16 GOOD & BAD of Mini Hydro Power
Head Measurement by Level
The principles of measurement by the levelling method
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Site Identification
17GOOD & BAD of Mini Hydro Power
Head Measurement by Water Level
This method is similar to the levelling method, except that a water-filled hose is used
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Site Identification
18 GOOD & BAD of Mini Hydro Power
Head Measurement by Pressure Gauge
What are the specifics of this simple head measurement method?
t 0OMZBQSFTTVSFHBVHFBOEBDMFBSQMBTUJDIPTFBSFOFFEFEt 0OMZUXPNBJOFSSPSTDBOBSJTF
- The gauge is not properly calibrated- There are air bubbles in the hose
t 'JSTU DBMJCSBUF UIF HBVHF TDBMF GSPN B MPX UP B IJHI SFBEJOH EP UIBU UJNFT UP HFUreliable results
t $IFDL UIF TJ[F BOE MFOHUIPG UIFIPTFCFDBVTF UIFXBUFSMMFEIPTFNVTUCF DBSSJFEaround the entire length from intake to tailrace
t 3FDPSEBMMEBUBPOBDIBSU
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Site Identification
19GOOD & BAD of Mini Hydro Power
Head Measurement by Barometer/Altimeter
Head is the difference of elevation 1 and 2
An altimeter is based on atmospheric pressure. The atmospheric pressure is different at different elevations. It decreases with increasing elevation above sea level.
When to use an altimeter?
t 6TFUIJTNFUIPEPOMZEVSJOHTUBCMFXFBUIFSDPOEJUJPOTt .FBTVSFNFOUTTIPVMECFDBSSJFEPVUJOBTIPSUUJNFt 1FSGPSNUIJTNFBTVSFNFOUTFWFSBMUJNFTBOEUIFODBMDVMBUFUIFBWFSBHFIFBEt %P OPU VTF UIJT NFUIPE GPS MPX IFBET #FDBVTF CBSPNFUFST IBWF DPOTJEFSBCMF
uncertainties this method should not be used for heads less than about 50 m
t 5IJT NFUIPE JT SFDPNNFOEFE BT B STU RVJDL NFBTVSFNFOU XIJDI MBUFS NVTU CFvalidated by more accurate measurements
Elevation 2 Turbine inlet
Elevation 1 Water level of forebay
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Site Identification
20 GOOD & BAD of Mini Hydro Power
Head Measurement by Clinometer
What is the use of a clinometer?
t %JFSFOUNFBTVSFNFOUTDBOCFQFSGPSNFEXJUIBDMJOPNFUFSt 'PSBOHMFNFBTVSFNFOUTUIFDMJOPNFUFSNVTUIBOHWFSUJDBMMZt 'PSTMPQFNFBTVSFNFOUTUIFDMJOPNFUFSNVTUCFIFMEBOEQPJOUFEXJUIUIFiwBU
the bottom/top of the point to be measured
t 'PSEJTUBODFNFBTVSFNFOUUIFDMJOPNFUFSNVTUCFIFMEBOEQPJOUFEXJUIUIFiiBUUIFbottom/top of the point
t #FTU BOE NPTU BDDVSBUF SFTVMUT BSF PCUBJOFE CZ FJUIFS TUFBEZJOH UIF IBOE PO UIFforehead or on a pole
t 'SPN UIF NFBTVSFNFOU UIF EJFSFODF JO IFJHIU CFUXFFO UIF UXP QPJOUT DBO CFcalculated
4 scales availableClinometer
Up- and downward measurements are
possible
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Site Identification
21GOOD & BAD of Mini Hydro Power
Head Measuring by Level Instrument
Why to use an automatic level instrument?
t .FBTVSFNFOUTBSFGBTUBOEBMTPXPSLGPSMPOHFSEJTUBODFTTVDIBTJOBUUFSSBJOJOTUFFQterrain, the instrument has to be set up more often
t 5IFBDDVSBDZPGNFBTVSFNFOUTJTWFSZIJHIJGUIFZBSFEPOFDPSSFDUMZt .BLFTVSFUIBUMFWFMJOTUSVNFOUJTTFUVQIPSJ[POUBMMZPOUIFUSJQPEt -FWFMJOTUSVNFOUTDBONFBTVSFPOMZJOBIPSJ[POUBMMJOFoOPEFFDUJPOJTQPTTJCMFt 5IF SFTVMUPGNFBTVSFNFOU JT UIFEJFSFODF
in height and distance between the two points where the rod is set up
t #Z SFDPSEJOH BMM NFBTVSFNFOUT BOE BEEJOHthem up, the distance and the height (which is the available head) can be calculated
t 5IJTNFUIPEJTTJNJMBSUPUIFPOFVTFEXJUIBclinometer but more accurate
backsight
foresight
La -b Lb -c
ChangePoint
O%
a
b
c
O% O%O%
foresight
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Site Identification
22 GOOD & BAD of Mini Hydro Power
Land Survey Instruments (Theodolite or Total Station)
Specifics of the high tech instruments:
t "UIFPEPMJUFDBONFBTVSFEJTUBODFTIFJHIUTBOEBOHMFTEBUBBSFSFDPSEFENBOVBMMZt " i5PUBM 4UBUJPOw EPFT UIF TBNF CVU UIF TVSWFZ EBUB BSF TUPSFE BVUPNBUJDBMMZ PO B
memory chip
t 5IFTFJOTUSVNFOUTBSFVTFECZQSPGFTTJPOBMMBOETVSWFZPSTt 'PS IFBE DBMDVMBUJPO POMZ TVDI JOTUSVNFOUT BSF OPU SFBMMZ OFDFTTBSZ CVU UIFZ DBOCF
very useful if larger areas have to be surveyed
Theodolite On site Total Station
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Site Identification
23GOOD & BAD of Mini Hydro Power
Head Measurement with High-Tech Instruments
These instruments should be used by people who are trained to handle them as well as to analyzethe data of the measurements
Altimeter Clinometer Leveling Instrument
Theodolite Total Station
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Site Identification
24 GOOD & BAD of Mini Hydro Power
1.3.7 General Project Data
Try to get an answer to the following questions:
t 8IFSFJTUIFQSPKFDUBSFBMPDBUFE oEFOFDPPSEJOBUFTCZ(14t 8IPXJMMCF UIFEFWFMPQFSPG UIFQSPKFDUNFBOTXIJDIPSHBOJ[BUJPOT TVQQPSUT UIF
project?
t 'JOEBQFSTPOXJUIJOUIFWJMMBHFGPSDPNNVOJDBUJPOBOZUJNFt 'JOEBQFSTPOXJUIJOUIFEFWFMPQFSPSHBOJ[BUJPOGPSDPNNVOJDBUJPOBOZUJNFt )PX JT UIFFMFDUSJDBM JOGSBTUSVDUVSFPG UIFWJMMBHFEFWFMPQFE "TTFTTFYJTUJOHHSJEXJUI
voltage and transformers/medium voltage lines with length and number of wires/low voltage lines with length and number of wires
t *TUIFSFHPPEBDDFTTJCJMJUZUPUIFOFYUWJMMBHFUPXONBSLFUBOETVQQMJFSTFUD oEJTUBODFin km and time should be recorded
t *TUSBOTQPSUBUJPOBWBJMBCMF UZQFBOEDPTUPGUSBOTQPSUBUJPOt "SFUIFSPBETBDDFTTJCMFBMMUIFZFBS t "SFOFJHICPSJOHWJMMBHFTPSIBNMFUTBMSFBEZDPOOFDUFEUPUIFFMFDUSJDHSJE t %SBXBOBQQSPYJNBUFNBQPGUIFWJMMBHFBOEJUTMPDBUJPOBOEDPOUFYU
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Site Identification
25GOOD & BAD of Mini Hydro Power
Demographic and Socio-Economic Parameters
t )PXNBOZIPVTFIPMETMJWFJOUIFNBJOWJMMBHFBOEJOJUTTVSSPVOEJOHBSFB t )PXNBOZQFSTPOTMJWFJOBOBWFSBHFIPVTFIPME t 8IBUJTUIFQPQVMBUJPOTHSPXUISBUFJOUIJTBSFB t 8IPIBTFMFDUSJDJUZBMSFBEZBOEIPXNBOZXBOUUPCFDPOOFDUFEUPBNJOJIZESPQPXFS
system?
t 3BUFQFPQMFTJOUFSFTUBOEVOEFSTUBOEJOHBCPVUUIFXBZUPCFDPNFiFMFDUSJFEwt 'JOE PVU UIF WBSJPVT TPVSDFT PG JODPNF o BHSJDVMUVSF USBEJOH TVQQMZ PG MBCPS
remittances, etc.
t &TUJNBUFUIFBWFSBHFNPOUIMZJODPNFPGBOBWFSBHFIPVTFIPMEt )PXNBOZ QFSTPOT BSF OPU FNQMPZFE BOE IBWF OP JODPNF PS SFDFJWF TVQQPSU GSPN
others?
t "SFUIFWJMMBHFSTXJMMJOHUPQBZGPSUIFVTFPGFMFDUSJDJUZBOEIPXNVDIDBOUIFZBPSEmonthly?
t "SFUIFSFBOZQVCMJDTVQQPSUTZTUFNTGPSQFSTPOTXJUIMPXJODPNF t 8IJDIFUIOJDHSPVQTMJWFJOUIFBSFB
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Site Identification
26 GOOD & BAD of Mini Hydro Power
1.3.8 Synergies, Ownership and Management
Try to consider following points:
t .BLFOPUFPGBOZSFDFOUPOHPJOHBOEGVUVSFJOGSBTUSVDUVSFEFWFMPQNFOUQSPKFDUTt $IFDLPVUPUIFSJOWPMWFNFOUTJOUIFWJMMBHFMJLF/(0THPWFSONFOUPSBJEBHFODJFTt (BVHFUIFBOUJDJQBUFEMFWFMPGDPNNVOJUZQBSUJDJQBUJPOt .BLFTVSFUIFSFJTFOPVHIJOWPMWFNFOUJOUBSJTFUUJOHNBLJOHQPMJDZEFDJTJPOTTVDIBT
how to handle payment defaulters etc
t 8IBUJTUIFBWBJMBCJMJUZPGMPDBMQFPQMFXJUINBOBHFNFOUCVTJOFTTTLJMMBTXFMMBTXJUIcivil, electrical and mechanical background?
t 'PSUIFIZESPQPXFSFOUFSQSJTFFYQMPSFBOEQSPQPTFEJFSFOUPXOFSTIJQNPEFMT FHcommunity-based, private, company-driven)
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Site Identification
27GOOD & BAD of Mini Hydro Power
1.3.9 Energy Supply and Demand
t *T UIFSF BOZ FMFDUSJD HSJE OFBS UIF WJMMBHF GPS DPOOFDUJPO *G TP DIFDL PVUXIBU JT UIFleast-cost option (electricity supply from the existing grid vs. setting up a stand-alone MHP scheme vs. selling surplus energy from the MHP to the grid)
t -VNQTVNQBZNFOUPSNFUFSFETFSWJDF t $MVTUFSJOHPSTFQBSBUFJOTUBMMBUJPOT t 8IBUJTUIFEPNFTUJDEFNBOEPGFBDIIPVTFIPME MJHIUJOHSBEJP57GBOSFGSJHFSBUPS
etc ask all households
t $IFDLUIFEFNBOEPGQVCMJDGBDJMJUJFTMJLFTDIPPMTNBSLFUDMJOJDDPNNVOJUZCVJMEJOHTstreet lighting, place of worship etc.
t "SF UIFSFBOZFYJTUJOH PSQSPQPTFEQSPEVDUJWFBQQMJDBUJPOT JO UIFWJMMBHFNJMMPGBOZtype, kiosk, manufacturing, cottage industry, etc.?
t 'JOEPVUBUXIBUUJNFBOEIPXMPOHUIFWBSJPVTEFNBOEJTOFFEFEBOEXIFOBOEIPXlong are the peaks of usage
t .BLF B TVNNBSZ PG BMM EFNBOE BOE DBMDVMBUF UIF EBJMZ UIF BOOVBM BOE UIF QFBLdemand for the village
t 'PSUIFEFTJHOBEEPSTPNFPUIFSQFSDFOUBHFGPSGVUVSFFYUFOTJPOTUPUIFTVNNBSZdemand
Example: see following page!
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Site Identification
28 GOOD & BAD of Mini Hydro Power
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Site Identification
29GOOD & BAD of Mini Hydro Power
1.3.10 Consultants
When to look for consultants?
If communities intend to implement an electrical system they are well advised to ask a consultant for support:
t "IZESPQPXFSTUBUJPOJODMVEJOHBOFMFDUSJDBMTZTUFNJTBDPNQMFYTVCKFDUBOEUIFIFMQof a reliable professional is very important. Only with such a professional you prevent mistakes in calculation, design, construction and operation
t *GBOFMFDUSJDBMTZTUFNTIPVMECFJOTUBMMFEUIFTPVSDFGPSUIFFOFSHZIBTUPCFTFMFDUFEvery carefully. Hydro, wind or solar potential will be checked in detail. The professional consultant will recommend the most appropriate energy system
Note:
SUCH SYSTEMS SHOULD NOT HARM THE ENVIRONMENT!
THIS FACT BECOMES MORE AND MORE IMPORTANT EVEN MHP IF NOT DESIGNED, BUILD AND OPERATED PROPERLY, CAN HARM THE ENVIRONMENT IN CERTAIN CASES!
MANY FACTS HAVE TO BE CONSIDERED BEFORE STARTING WITH HYDRO 108&345"5*0/%&4*(/
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2. Civil Works
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32 GOOD & BAD of Mini Hydro Power
2.1 CONSTRUCTION BASICS
This chapter will provide general advice for construction and show a number of good and bad examples to illustrate what makes the important difference.
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How to make concrete
What has to be considered for good workmanship?
t 5IFRVBMJUZPG DPODSFUFEFQFOETPO UIF DPSSFDUQSPQPSUJPOTPG BMM UIF JOHSFEJFOUT JFcement, sand, gravel and water
t /PUFOPVHIDFNFOUJOUIFNJYNBLFTXFBLMPXTUSFOHUIDPODSFUFt 5PPNVDIXBUFSBMTPNBLFTQPPSRVBMJUZDPODSFUFt *U JT JNQPSUBOUUPNFBTVSFBOEBEEBHHSFHBUFTQMVTTBOETFQBSBUFMZGPSNBLJOHEFOTF
concrete of good quality
t 6TFPOMZDMFBOBHHSFHBUFT
Note:
THERE IS NEVER AN ALTERNATIVE TO GOOD QUALITY WORKMANSHIP!
Cement Sand Gravel
Good quality concrete
Water
+ +
+ =
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34 GOOD & BAD of Mini Hydro Power
Construction of anchor block
What has to be considered for good workmanship?
t (PPEQSFQBSBUJPOJTFTTFOUJBMGPSHPPEDPODSFUFt %POPUESPQUIFDPODSFUFJOUPUIFGPSNXPSLGSPNBOZIFJHIUCVUMFUJUTMJQt .BYJNVNESPQPGDPODSFUFJTNPUIFSXJTFUIFBHHSFHBUFTHFUTFQBSBUFEt "WPJEDPMEKPJOUTEVSJOHDPODSFUJOHEPPOFTFDUJPOJOPOFMJGUt .BLFTVSFDPODSFUFMMTBMMWPJETVTFBWJCSBUPSTUJSEVSJOHQPVSJOHLOPDLPOGPSNXPSL
from outside etc
Measure & mix the ingredients with care
Let the concrete slip into the formwork
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GOOD & BAD of Mini Hydro Power
Anchor block ready for concreting
What has to be considered for good workmanship?
t 5IFCPBSETPGUIFGPSNXPSLBSFPGHPPERVBMJUZt 5IF TVQQPSUT BSF GBTUFOFE UP UIF GPSNXPSL BOE CSBDFE BHBJOTU UIF HSPVOE UP BWPJE
movements during placing the concrete
t 1VEEMFBOHFTBSFXFMEFEUPUIFQFOTUPDLQJQFUPCFUUFSBODIPSJUt 3FJOGPSDFNFOUJTJOQMBDFBOESFBEZGPSDPODSFUJOHt 'PSNXPSLNVTUCFXFMMYFECFDBVTFJUJTJNQPTTJCMFUPIPMEJUVQXIFOUIFDPODSFUFJT
being poured into the formwork
t #FGPSF QPVSJOH DMFBSMZ NBSL UIF OFDFTTBSZ UPQ PG DPODSFUF TVSGBDF UP HFU FOPVHIcoverage of reinforcement, at least 3 cm
t 7JCSBUFDPODSFUFXFMMoUIJTXJMMHJWFDPODSFUFUIFEFOTJUZBOEMMBMMWPJETTPJUIBTUIFstrength and quality to fulfill the task of an anchor block
Puddle flange welded on pipe
Supports all around the formwork
Corner bracing
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36 GOOD & BAD of Mini Hydro Power
Construction details of equipment foundation
What has to be considered for good workmanship?
t 5IFGPVOEBUJPOTPGUVSCJOFBOEHFOFSBUPSNVTUCFCVJMUXJUIDBSFt "TUBCMFGPVOEBUJPOBWPJETNPWFNFOUTPGUIFFRVJQNFOUXIJDIJTBCTPMVUFMZOFDFTTBSZ
for a trouble-free operation of the plant
t 5IFHFOFSBUPSTIPXOJOUIFQJDUVSFJTQSPQFSMZGBTUFOFEBOEBEKVTUFECZUVSOCVDLMFTUPkeep the equipment stable and horizontal while the concrete is being placed
t "OBCTPMVUFMZIPSJ[POUBMCBTFJTFTTFOUJBMGPSBTNPPUIUSBOTNJTTJPOt 5IFFBSUIJOHDBCMFJTDPOOFDUFEUPUIFSFJOGPSDFNFOUPGUIFCBTFBOEXJMMCFMBUFSBMTP
connected to the equipment itself. This is very important to avoid short circuits during operation
t *OPSEFSUPHFUHPPERVBMJUZDPODSFUFUIFDPODSFUFNVTUCFWJCSBUFEBGUFSCFJOHQPVSFE
Steel base fixed to rods
Earthing cable connected to reinforcement
Earthing cable
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GOOD & BAD of Mini Hydro Power
'BTUFOJOHPGFRVJQNFOUUPDPODSFUFPPSXJUIPVUCVJMEJOHBGPVOEBUJPO
What has to be considered for good workmanship?
t *G OP OFX GPVOEBUJPO JT UP CF CVJMU FRVJQNFOU DBO BMTP CF YFE UP UIF DPODSFUF BTshown above and described below
t 5IJT NFUIPE JT BMTP BQQMJDBCMF XIFO B GBTUFOJOH CPMU CFDPNFT MPPTF BOE NVTU CFrepaired
t %SJMM B WFSUJDBM IPMF JO UIF DPODSFUF PPS BOENBLF TVSF UIBU UIF UPQ EJBNFUFS JT OPUlarger than the diameter of the bottom of the hole
t 'PSHSPVUJOHVTFPOMZIJHIEFOTJUZNPSUBSOPOTISJOLBOETMPXTFUUJOHt 1PVS NPSUBS STU BOE UIBO JOTFSU CPMU WFSUJDBMMZ TFU FRVJQNFOU PO UPQ o EVSJOH UIJT
operation the mortar is still soft and all parts are adjustable
Screw thread on steel rod
Equipment base
Steel plate must overlap hole in concrete by at least 30 mm all around
)PMFJODPODSFUFPPSBQQSPYYEJOEJBNFUFSIt must not be larger at the top than the bottom
Small plates welded to screw rod and washer (to prevent rotation)
Thick washer (approx, 4d x 5 mm thick) welded to rod
Sheet metal packing 16 mm25 mm
-FWFMPGDPODSFUFPPS
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38 GOOD & BAD of Mini Hydro Power
Earthing must be done properly for the sake of safety
What has to be considered for good workmanship?
t &BSUIJOHJTBTBGFHVBSETZTUFNGPSQFPQMFBOENBDIJOFTt &BSUIJOHDBCMFNVTUIBWFBHPPEDPOOFDUJPOUPUIFFBSUIJOHSPEt 6TF0/-:BQQSPWFEFBSUIJOHDMBNQTt -FOHUIPGFBSUIJOHQPMFEFQFOETPOUIFDPOEVDUJWJUZPGUIFHSPVOECVUNVTUCFBUMFBTU
3 m long
t &BSUIJOHTIPVMECFMBJEBSPVOEUIFQPXFSIPVTFBUUIFGPVOEBUJPOMFWFMt $POOFDUBMMSFJOGPSDFEDPODSFUFGPVOEBUJPOTQPXFSIPVTFBOEQPXFSFRVJQNFOUBOE
any other electrical equipment to the earthing ring
t -JHIUOJOHDPOEVDUPSUPCFDPOOFDUFEUPFBSUIJOHSJOHo 1 m above groundt 5IJTDPOOFDUJPOXJMMCFVTFEUPNFBTVSFUIFSFTJTUBODFGPSOEJOHPVUJGUIFFBSUIJOHJT
still functioning as it should be
Note:
EARTHING IS A SAFEGUARD FOR PEOPLE AND MACHINES!
NO EARTHING oDEADLY DANGER!
Earthing cable
Earthing rod
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GOOD & BAD of Mini Hydro Power
%FBMJOHXJUITVSGBDFXBUFSIFSFVODPOUSPMMFEXBUFSPX
What has to be considered for good workmanship?
t 1SPQFSESBJOBHFPGBMMTUSVDUVSFTJTOFDFTTBSZGPSMPOHFSMJGFFYQFDUBODZt 5IFCBTFPGTUSVDUVSFTFH GPVOEBUJPOPGQPXFSIPVTFQFOTUPDLTVQQPSUTFUDDBOCF
easily destroyed by water, unless they have a stable concrete foundation
t 'MPXJOHTVSGBDFXBUFSXJMMXBTIPVUTPJMBOEDBVTFFSPTJPOVOEFSOFBUITUSVDUVSFTBOEfoundations - keep an eye on surface water where it comes from and where it goes
t 8BUFSEJTDIBSHFJTBOJNQPSUBOUTVCKFDUPGDPOTUSVDUJPOoEPOPUOFHMFDUJU
Note:
WATER CAN BE A HAZARD TO STRUCTURES!
Washed out
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40 GOOD & BAD of Mini Hydro Power
Big structure without static design
What has to be considered for good workmanship?
t 'PSBMMTUSVDUVSFTFTQFDJBMMZGPSCJHPOFTJUJTFTTFOUJBMUPIBWFBTUBUJDTUSVDUVSBMEFTJHObefore construction works starts
t $IPPTFNBUFSJBMBDDPSEJOHUPEFTJHOBOESFRVJSFETUSFOHUIt $BSSZPVUXPSLTWFSZDBSFGVMMZBOEGPMMPXUIFBEWJDFPGUIFFOHJOFFSt 8FBLBOEVOTUBCMFXBMMDPOTUSVDUJPOTDBOCFBIB[BSEUPQFPQMFXIFODPMMBQTJOHt 5IF PPE GPMMPXJOH B CSPLFO SFUBJOJOH XBMM JT WFSZ EBOHFSPVT UP QFPQMF XIP MJWF
downstream
Wall is too high compared to thickness
No concrete foundation
Material is not suitable
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GOOD & BAD of Mini Hydro Power
Gabion used for weir construction
What has to be considered for good workmanship?
t 5IF EJNFOTJPO PG UIF MPXFTU SPX PG HBCJPOT NVTU CF MBSHFS UIBO UIF NBY XBUFSpressure, e.g. if the water is 1 m deep, the lowest gabion should be 1.2 m
t "MMTUFQTPGUIFHBCJPOXFJSNVTUCFBCPWFXBUFSQSFTTVSFMJOFt 5PSFBDICFUUFSTUBCJMJUZPGUIFDPOTUSVDUJPOEJHUIFMPXFTUHBCJPOJOUPUIFSJWFSCPUUPNt 5JFUIFHBCJPOFOETJOUPUIFSJWFSCBOLTPSJOUPXJOHXBMMTt "TBMUFSOBUJWFUPBTUSBJHIUBMJHONFOUTFUUIFHBCJPOTJOBOVQTUSFBNDVSWFt 'PSCFUUFS GSJDUJPO UIF MFOHUIPG UIFVQQFSHBCJPOTIPVMECFPG UIF MFOHUIPG UIF
lower one
t .BLFTVSFUIBUUIFNBYJNVNTJ[FPGUIFXJSFNFTIJTDNEFOJUFMZTNBMMFSUIBOUIFsmallest cobbles in the gabions
t $POOFDUBMMHBCJPOTUPFBDIPUIFSt 6TFPOMZXJSFNBUFSJBMUIBUEPFTOPUSVTUTVDIBTHBMWBOJ[FEPSFQPYZDPBUFE
Good design
Mesh width ~ 5cm
Max water level
Max water pressure
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Civil Works
42 GOOD & BAD of Mini Hydro Power
Headrace channel too close to a steep slope
What has to be considered for good workmanship?
t 5IFTJEFXBMMTPGBDIBOOFMNVTUCFBCMFUPXJUITUBOEUIFXBUFSQSFTTVSFt 5IFXBUFSQSFTTVSFJTBUUIFIJHIFTUBUUIFCPUUPNPGUIFDIBOOFMt #VJME UIF DIBOOFM BT B SJHJE CPY BOEPS EJH UIF DIBOOFM JO EFFQFS XJUI FOPVHI
undisturbed material remaining on the down slope side
t *G UIFSF JT OP PUIFS BMJHONFOU QPTTJCMF VTF NBUFSJBM XIJDI DBO XJUITUBOE UIF XBUFSpressure o use concrete on a good base foundation
t 5IFBSFBBSPVOEUIFDIBOOFMTIPVMECFXFMMESBJOFEUPMJHIUFOBOZXBUFSQSFTTVSFBOEkeep the slope from sliding
Sand bags are not enough support
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Civil Works
GOOD & BAD of Mini Hydro Power
Broken channel invert caused by erosion and sliding
What has to be considered for good workmanship?
t "DIBOOFMVTVBMMZDPOTJTUTPGUXPTJEFXBMMTBOEBOJOWFSUCFE
t *G B DIBOOFM IBT OP VQTMPQF SFUBJOJOH XBMM XBUFS XJMM TFFQ UISPVHI VOEFSOFBUI UIF
channel and erode and damage the bed
t 5IFNPOFZTBWFECZOPUCVJMEJOHBOVQTMPQFXBMMXJMMIBWFUPCFTQFOUGPSSFQBJSTPGUIFchannel this becomes more expensive because the channel invert must be repaired too
t *U JTBHPPE JOWFTUNFOU UPCVJMEB SFUBJOJOHXBMMPO UIFVQTMPQFTJEFVOMFTT UIFSF JTBstable rock face where only a thin liner is needed
t 6QTMPQFSFUBJOJOHXBMMTBMTPIFMQUPQSFWFOUUIBUFSPEFENBUFSJBMESPQTJOUPUIFDIBOOFMt .BLF TVSF UIBU UIF TMPQF BSPVOE UIF DIBOOFM JTXFMM ESBJOFE UP LFFQ UIF TMPQF GSPN
sliding, place drainpipes underneath the channel
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44 GOOD & BAD of Mini Hydro Power
2.2 INDIVIDUAL COMPONENTS
2.2.1 Weir and Intake
Main elements of a weir and intake structure
Main functions and design principles of weir & intake structure:
*OUBLF NVTU EJWFSU UIF SFRVJSFE TUSFBN PX JOUP UIF IFBESBDF DIBOOFM BU BMM UJNFT BOEall water levels in the river
Intakes should if possible be located on the outer side of a river bend to minimize sediment in headrace
1SPWJTJPOT TIPVME CF NBEF UP FYDMVEF MBSHF PBUJOH EFCSJT PBUJOH CBS PS TVCNFSHFEJOUBLFPSJDFBOEDPBSTFHSBWFMCPUUPNTJMMGSPNUIFPXEJWFSUFEJOUPUIFIFBESBDF
5IF TMVJDF HBUFNVTU CF JOTUBMMFE DMPTF UP UIF JOUBLF PSJDF JO PSEFS UP BMMPX VTIJOH PGsediments depositing in front of the intake orifice
Weir or diversion structure
Sluice gate
Optional: Gravel trap with flushing gate
Intake gate or stop log on sill
Sand trap
Flushing gate
Optional: coarse trash rack
Headrace
Side spillway
Intake orifice
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3D sketch of weir and intake
Main elements of an intake:
This drawing shows a typical combination of weir and intake including a sluice gate which can be used to remove deposited sand and gravel from the intake. The main function of the intake is to allow a certain amount of water into the sand trap and headrace and to keep TFEJNFOUTBOEPBUJOHEFCSJTBXBZGSPNUIFIFBESBDFTZTUFN&YDFTTXBUFSNVTUCFSFUVSOFEinto the river.
Wing wall
Weir
Sluice gate
Intake gate
Intake orifice
Flow to sand trap
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46 GOOD & BAD of Mini Hydro Power
Most elements of a proper weir and intake structure are missing
How can I improve it?
t #VJME B XFJS FRVJQQFE XJUI PWFSPX TQJMMXBZ TMVJDF HBUF BOE JOUBLF HBUF UP UIFheadrace or a properly dimensioned intake opening with stop log grooves
t 5IFIFBESBDFTIPVMECFCVJMUPGDPODSFUFNBTPOSZPSTJNJMBSNBUFSJBMt 4JEFBOEXJOHXBMMTVQBOEEPXOTUSFBNPGUIFXFJSBSFFTTFOUJBM
Why?
t 5IFSJWFSCFEVQTUSFBNPGUIFXFJSNVTUCFVTIFESFHVMBSMZUPQSFWFOUTFEJNFOUTGSPNentering the headrace
t "O FMFWBUFE JOUBLF HBUF PS JOUBLF PQFOJOH JT OFFEFE UP DPOUSPM UIF PX JOUP UIFheadrace and prevent sediments from entering
t *GUIFSFJTOPHBUFTUPQMPHTDBOCFVTFEUPDMPTFUIFPQFOJOHGPS0.t 8JUIPVUQSPQFSTQJMMXBZUIFXFJSTUSVDUVSFNBZCFFSPEFEBOEEBNBHFEEVSJOHPPETt 8JUIPVUXJOHXBMMTBOETJEFXBMMTUIFSJWFSCBOLTXJMMCFFSPEFE
NO side walls
NO sluice gate
Only earth channel as headrace
NO intake structure
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GOOD & BAD of Mini Hydro Power
Main elements of a weir and intake structure
Why is this a good example?
t "MMFMFNFOUTOFDFTTBSZGPSBXFMMGVODUJPOJOHJOUBLFBSFJODMVEFEJOUIJTTUSVDUVSFt 5IFNBJOFMFNFOUTBSFXFMMBSSBOHFEt 5IFRVBMJUZPGDPOTUSVDUJPOJTHPPEt 5IFTUSVDUVSFJTXFMMNBJOUBJOFEt (BUFTBOEBDDFTTUPUIFHBUFTJTDPWFSFECZBSPPG
Stilling basin
WeirSluice gate
Cover over both gates
Intake gate
Headrace to forebay /
powerhouse
Side walls on both sides
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48 GOOD & BAD of Mini Hydro Power
Examples of unsuitable dam materials
Dam structure has shifted already
Rocks and plastic sheets do NOT make a good dam
Gabions cannot with-stand flood flows
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GOOD & BAD of Mini Hydro Power
Concrete weirs can last for a long time
Why are these good examples?
t $PODSFUFDPODSFUFNBTPOSZJTUIFQSFGFSSFENBUFSJBMGPSCVJMEJOHXFJSTt .BTTDPODSFUFXJMMXJUITUBOEUIFIJHIIZESBVMJDMPBETEVSJOHPPETt $PODSFUFJTBTUSPOHEVSBCMFNBUFSJBMBMTPSFTJTUBOUUPDIFNJDBMTt $PODSFUFDBOCFVTFEGPSBOZUZQFPGXFJS
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50 GOOD & BAD of Mini Hydro Power
An unstable construction
How can I improve it?
t #VJMEDPODSFUFDPMVNOTPOCPUITJEFTt 4VQQPSUUIFGSBNFZPLFPGUIFHBUFTPMJEMZ
Why?
t 5IFHBUFTMJEFTJOTJEFUIFGSBNFt *G UIF GSBNF HFUT CFOU PS UXJTUFE UIF HBUF XJMM OPUNPWF BOZNPSF t PX DBOOPU CF
controlled
t 5IFGSBNFDPVMEBMTPHFUCFOUPSUXJTUFECZBPPEJOUIFSJWFSPSTPNFPUIFSJODJEFOUTVDIBTPBUJOHEFCSJT
Columns on both sides missing
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GOOD & BAD of Mini Hydro Power
The columns are good supports for the gate
Why is this a good example?
t 5IFGSBNFPGUIFHBUFTIPVMECFCVJMUBTBTPMJEXBMMPSJOTUSPOHDPMVNOTt 5IFTUFFMGSBNFNVTUCFLFQUTUSBJHIUBMMUIFUJNFUPMFUUIFHBUFTMJEFJOUIFSBJMTt 5IFHBUFNVTUCFBCMFUPCFNPWFEUPDPOUSPMUIFPXUPUIFTBOEUSBQBOEGVSUIFSPO
to the headrace and forebay
Solid columns
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52 GOOD & BAD of Mini Hydro Power
Points for operation and maintenance
What must I do to keep system running well?
1 Daily : Keep the intake orifice clean
2 8FFLMZ $IFDLGPSEFQPTJUTJGUIFSFBSFBOZVTIBUJOUBLFHBUF3 Monthly : Flush through sluice gate to clean upstream basin
4 As needed : Apply grease on wheels and threads of the gates
5 %VSJOHBGUFSPPE $IFDLGPSCBOLFSPTJPOCFIJOEXJOHXBMMT6 %VSJOHBGUFSPPE $IFDL GPS FSPTJPO BOE EBNBHF JO TUJMMJOH CBTJO BOE on
downstream banks
Note:
IF ANY PROBLEMS ARE FOUND, REPAIRS MUST BE MADE IMMEDIATELY!
1
2
4
53
6
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GOOD & BAD of Mini Hydro Power
2.2.2 Sand Trap - Settling Basin
Main construction details of a sand trap/settling basing
Weir or diversion structure
Sluice gate
Optional: Gravel trap with flushing gate
Intake gate or stop log on sill
Side spillway
Cross Section A-A'
Long Section
Sand trap
Headrace or Penstock
Trash rack if penstock follows
Bottom outlet with gate for flushing
SpillwayFrom Intake
Intake channel
A'
A'
0.25 0.250.60 0.10
0.20
0.80
0.250.800.25
0.20
2.00 5.00 1.00
0.80
Intake orifice
Side spillway
Flushing gate
Optional: coarse trash rack
Headrace
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Civil Works
54 GOOD & BAD of Mini Hydro Power
There are a number of problems with this intake
How can I improve it?
t #VJMEBDPODSFUFXBMMGVSUIFSCBDLPOUIFIJMMTJEFCBOLt $VUCBDLBMMTISVCTBOENBJOUBJOSFHVMBSMZt 4QJMMXBZTIPVMECFMPDBUFEBUUIFFOEPGUIFTBOEUSBQ/05JOUIFIFBESBDFtrap
Why?
t 0OHPJOHTDPVSJOHCZXBUFSXJMMDBVTFUIFCBOLUPFSPEFt 4FUUMJOHPVUPGTFEJNFOUXJMMCFMFTTFFDUJWFJGPXJTOPUMJOFBSt 4FEJNFOUT GSPN CBOL FSPTJPOXJMM TJMU VQ UIF IFBESBDF BOEXJMM IBWF UP CFNBOVBMMZ
SFNPWFECFDBVTFUIFSFJTOPVTIJOHHBUF
Shrubs need cutting
NO bank protection
Vortices erode bank
NO flushing gate
NO Spillway
Headrace
Intake structure
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55
Civil Works
GOOD & BAD of Mini Hydro Power
This picture shows all main elements of a well designed water intake with sandtrap
Why is this a good example?
t 5IFUSBOTJUJPOJTJNQPSUBOUUPDBMNBOETMPXEPXOUIFPXWFMPDJUZt 4FEJNFOUTTFUUMFPVUNPSFFBTJMZXIFOUIFWFMPDJUZJTMPXBOEUIFPXJTMJOFBSt 5IFTQJMMXBZDPOUSPMTUIFNBYJNVNWPMVNFPGPXJOUPUIFIFBESBDFt 4UPQ MPH HSPPWFT BMMPX UIF JOTFSUJPO PG CPBSET UP CMPDL UIF PX GPS DMFBOJOH BOE
repairing the headrace
But:
t 'PSBTBOEUSBQUIFCBTJOJTUPPTIPSUUIFPXWFMPDJUZJTUPPIJHIBOEUIFTBOENBZOPUsettle down
t *G UIF TBOE TFUUMFT EPXO UIFSF JT OP VTIJOH HBUF BOE UIF TBOE NVTU CF SFNPWFEmanually
Spillway
Gate Sluice gate Weir Wingwalls
Sandtrap
Headrace to forebay
Grooves for stop logs
Overflow channel
Transition
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Civil Works
56 GOOD & BAD of Mini Hydro Power
Issues for operation and maintenace of a sandtrap
What must I do to keep the system running well?
1 3FNPWFBOZSFNBJOJOHTFEJNFOUNBOVBMMZBGUFSVTIJOHUIFTBOEUSBQ2 Clean concrete surface from vegetation
3 Repair broken parts of the sandtrap
4 Check gates and/or stop logs to be ready for use (not shown in the picture)
5 Remove all grass, shrubs, debris and dirt and do it regularly
Note:
SEDIMENT PARTICLES MAY DAMAGE PENSTOCK AND TURBINE!
CHECK AT LEAST ONCE A MONTH!
1
2
5
3
2
5
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57
Civil Works
GOOD & BAD of Mini Hydro Power
2.2.3 Headrace Channel
Examples of headrace channels
What do I have to consider regarding headrace channels?
t "WPJEFBSUIDIBOOFMTJGQPTTJCMFBUBMMo higher maintenance and higher risk of erosion material which could reach the turbine
t $VUTMPQFTCBDLGSPNDIBOOFMUPBWPJEFSPEFENBUFSJBMPSSPDLTGSPNESPQQJOHJOUPUIFheadrace channel
t 3FUBJOJOHXBMMTNVTUBMXBZTCFESBJOFEXFMMXJUIXFFQJOHIPMFTUPBWPJETMJEJOHTMPQFTt $PWFSFEDIBOOFMDPVMEBMTPCFSFQMBDFECZBCVSJFEQJQFo high costst ,FFQBSFBBMPOHUIFDIBOOFMGSFFPGWFHFUBUJPOo cut back regularly
Lined channel - masonry
Covered channel because of rockfalls or eroded material
Concrete lined channel Sealed channel Clay or concrete slurry
Simple earth channel
Drainage below channelis needed on water-
saturated slopes
Cover of channel where rock PXBOEFSPEFENBUFSJBM
cannot be halted
Retaining wall
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Civil Works
58 GOOD & BAD of Mini Hydro Power
Avoid steep eroding banks along headrace channel
How can I improve it?
t %POPUCVJMEIFBESBDFDIBOOFMDMPTFUPTUFFQFSPEJOHTMPQFTt $VUCBDLTMPQFTTPUIFSFJTOPFSPTJPONBUFSJBMDBSSJFEJOUPDIBOOFMt $IFDLIFBESBDFDIBOOFMSFHVMBSMZBOEDMFBOBTOFFEFEt *O TFDUJPOTXIFSF FSPTJPONBUFSJBM DBOOPU CF QSFWFOUFE DPWFS UIF DIBOOFM FH XJUI
wooden boards
t 3FNPWFFSPTJPONBUFSJBMBOETFEJNFOUTGSPNUIFDIBOOFM
Why?
t 4UFFQCBOLTXJUIPVUWFHFUBUJPOtNPSFFSPTJPONBUFSJBMJOUIFDIBOOFMt &SPTJPONBUFSJBMDBOTJMUVQBOEFWFOUVBMMZCMPDLUIFDIBOOFMt &SPTJPONBUFSJBMTFEJNFOUBMTPSFEVDFTUIFPXDBQBDJUZt &SPTJPONBUFSJBMDPVMEEBNBHFUIFUVSCJOFJGOPUDBVHIUJOUIFTBOEUSBQ
Erosion material will fall into headrace
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GOOD & BAD of Mini Hydro Power
The channel should be free of vegetation and away from steep slopes
Why is this a good example?
t 5IFBSFBBMPOHUIFIFBESBDFDIBOOFMJTGSFFPGWFHFUBUJPOo less debris from vegetation in the channel
t *GTUFFQTMPQFTBSFBXBZPSDVUCBDLGSPNUIFFEHFPGUIFDIBOOFMUIFSFJT MFTTSJTLPGdirt and sediment dropping into the headrace
t 1SPQFSNBJOUBJOFE HSBTT JT B HPPE DIPJDF GPS FBSUI TMPQF JU TUBCJMJ[FT UIF CBOLT BOEreduces erosion
t *OTQFDUJPOGPSPQFSBUJPOBOENBJOUFOBODFBMPOHUIFDIBOOFMXJMMCFFBTZ
But:
t 5IFEJUDICFUXFFO UIF DIBOOFM BOE UIF TMPQFNVTUCF DMFBOFE GSPNEFCSJT BOELFQUopen
Area is free of shrubs
BUT : remove debris from this ditch
Cut back slope from edge of channel
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Civil Works
60 GOOD & BAD of Mini Hydro Power
Headrace channel must be free of vegetation
How can I improve it?
t $IFDLIFBESBDFSFHVMBSMZBOEDVUCBDLWFHFUBUJPOt 3FNPWFQMBOUTMFBWFTEFCSJTFUDGSPNUIFDIBOOFMSFHVMBSMZ
Why?
t 7FHFUBUJPO JO UIF IFBESBDF SFEVDFT UIF PX WFMPDJUZ BOE DBQBDJUZ XIJDI XJMM DBVTFNPSFTFEJNFOUBUJPOJOUIFDIBOOFMBOEMFTTPXUPUIFQPXFSIPVTF
t 5PPNBOZMFBWFTJOUIFIFBESBDFNBZDMPHUIFUSBTISBDL
Vegetation like a jungle
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61
Civil Works
GOOD & BAD of Mini Hydro Power
Vegetation well cut along the left bank
Why is this a good example?
t 5IFBSFBBMPOHIFBESBDFDIBOOFMJTLFQUGSFFPGEJTUVSCJOHWFHFUBUJPOt (SBTTBOETISVCTBSFDVUUPLFFQQBUIBOEMFGUDIBOOFMCBOLGSFF
Note:
THE SLOPE ON THE RIGHT SIDE IS VERY STEEP AND EROSION MATERIAL WILL EASILY DROP IN THE EARTH CHANNEL. MAINTENANCE IS VERY IMPORTANT IN THIS SECTION OF THE HEADRACE!
TRY TO STABILIZE THE STEEP SLOPE WITH VEGETATION AND/OR OTHER BIO-ENGINEERING MEASURES!
Free of vegetation
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Civil Works
62 GOOD & BAD of Mini Hydro Power
Earth channel can erode easily when velocity is too high
How can I improve it?
t -JOFUIFDIBOOFMXJUINBTPOSZPSDPODSFUFJGQPTTJCMFt #VJMEESPQTJOUIFDIBOOFMUPSFEVDFUIFWFMPDJUZPGUIFPXt 1SPUFDUUIFESPQTXJUISJQSBQBHBJOTUCFEFSPTJPOt 1SPUFDUUIFPVUFSDVSWFPGFBSUIDIBOOFMTXJUISPDLTSJQSBQUPSFEVDFFSPTJPOt 1SJPSUPDPOTUSVDUJPOESBXBMPOHJUVEJOBMTFDUJPOUPEFUFSNJOFUIFPQUJNBMTMPQFCBTFE
on the proposed channel material
Why?
t 5IFTMPQFPGUIFDIBOOFMEFUFSNJOFTUIFWFMPDJUZPGUIFPXt 5IF GPSDFPGPXJOHXBUFSDBODBVTFFSPTJPOEFQFOEJOHPO UIFDIBOOFMNBUFSJBMBOE
slope
t $IBOOFMTXJUIUPPTUFFQTMPQFTPXUPPGBTUBOEUIVTXJMMFSPEFGBTUFSt $IBOOFMTXJUITMPQFTUPPBUXJMMCFCMPDLFECZTFUUMFETFEJNFOUTt #VJME DIBOOFM TMPQF BDDPSEJOH UP SFDPNNFOEFE WFMPDJUJFT JO DIBOOFMT VOOFDFTTBSZ
drops reduce the available head for MHP:- Earth channel : < 0.4 m/s- Masonry lining : < 2.0 m/s
$PODSFUFMJOJOH NT .JOJNVNWFMPDJUZ NTUPBWPJETFEJNFOUBUJPO
Velocity is too fast
Eroded slope
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Civil Works
GOOD & BAD of Mini Hydro Power
Headrace channel is free of vegetation
Why is this a good example?
t 4JEFTMPQFJTXFMMCBDLGSPNFEHFPGDIBOOFMt 5IFSFJTOPWFHFUBUJPOHSPXJOHJOUPUIFDIBOOFMt "TBDPOTFRVFODFZPVDBOFYQFDU
- less debris in the channel - a clean trash rack - well operating turbine- efficient electricity generation - happy consumers
Slope is set back
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Civil Works
64 GOOD & BAD of Mini Hydro Power
Headrace in a deep and steep cut section
How can I improve it?
t *GUIFDVUJTOPUTUBCMFCVJMESFUBJOJOHXBMMTUPQSFWFOUFSPTJPONBUFSJBMGSPNGBMMJOHJOUPthe channel
t $PWFSUIFIFBESBDFXJUIQSFGBCDPODSFUFTMBCTPSXPPEFOCPBSETt 3FQMBDFUIFPQFOIFBESBDFDIBOOFMXJUIBCVSJFEQJQF
Why?
t %FFQBOETUFFQDVUTXJMMBMXBZTCFQSPOFUPCBOLFSPTJPOt &YDFTTJWFNBJOUFOBODFPGTUFFQCBOLTNBZCFWFSZDPTUMZt 4UFFQCBOLTNBZTMJEFBOECMPDLDIBOOFMDPNQMFUFMZ
Note:
SEDIMENT PARTICLES MAY DAMAGE PENSTOCK AND TURBINE!
Suggested retaining wall
Slopes are too steep
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Civil Works
GOOD & BAD of Mini Hydro Power
Retaining wall stabilizes the toe of the slope
Why is this a good example?
t "SFUBJOJOHXBMMSFEVDFTUIFOBUVSBMBOHMFPGSFQPTFPGUIFTMPQFt -FTTFSPTJPONBUFSJBMXJMMGBMMJOUIFIFBESBDFt .BJOUFOBODF PG UIF IFBESBDF JT FBTJFSo less sediment, which however still must be
removed
t 5IFSFBSFOBSSPXXBMLXBZTBMPOHUIFDIBOOFMGPSFBTJFSNBJOUFOBODF
Space to walk
Retaining wall
Slopes are set back from headrace
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Civil Works
66 GOOD & BAD of Mini Hydro Power
This a not a good creek crossing
How can I improve it?
t 3FQMBDFUIFXPPEFOTVQQPSUTXJUIDPODSFUFDPMVNOTVQQPSUTt 4FUUIFTVQQPSUTPOHPPEGPVOEBUJPOTFTQFDJBMMZVOEFSXBUFSt "EEBODIPSCMPDLTPOCPUITJEFTPGUIFTUSFBNUPTVQQPSUUIFQJQF
Why?
t 1JQFDSPTTJOHTOFFETUBCMFTVQQPSUTPUIFSXJTFUIFQJQFNBZCVDLMFBOEDPMMBQTFt 8PPEFOTVQQPSUTNBZSPUSBUIFSRVJDLMZXJUIUJNFUIFQJQFXJMMTJOLBOEXJMMFWFOUVBMMZ
fail
t "TJOLJOHQJQFDBVTFTUIFBOHFDPOOFDUJPOTUPDPNFMPPTF
Shaky supports
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67
Civil Works
GOOD & BAD of Mini Hydro Power
Well-built pipe crossings in a headrace
Why is this a good example?
t 5IFDPOOFDUJPOPG UIFPQFOIFBESBDFDIBOOFM UP UIFQJQFDSPTTJOH JTBTPMJEDPODSFUFstructure
t 5IFTQJMMXBZVQTUSFBNPGUIFQJQFJOMFUJTBHPPETPMVUJPOUPEJTDIBSHFFYUSBPPEXBUFSit does not seem to affect the stability of the abutments
t 5IFTJ[FPGUIFDSPTTJOHQJQFJTMBSHFFOPVHIUPDBSSZUIFPXJOUIFIFBESBDFUIFSFGPSFthe pipe cross section equals the wetted area of the channel
t 5IF QJQF JOMFU TIPVME IBWF B TNPPUI SPVOEFE USBOTJUJPO UP SFEVDF IFBE MPTTFT BOEbackwater effects
t 5IF TQJMMXBZ JT MPDBUFEVQTUSFBNPG UIF DSPTTJOHQJQF JG UIFSF JT UPPNVDICBDLXBUFSeffect, the water will be spilled in a controlled way
Spillway
Storm water creekStable abutments
Strong supports
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Civil Works
68 GOOD & BAD of Mini Hydro Power
What must I do to keep system running well?
1 Remove sediment and rocks from the channel
2 Cut grass and shrubs, and remove debris do it regularly
3 Check slopes for erosion
Repair broken parts of the headrace
Check functionality of stop logs and spillways - if existing
Note:
SEDIMENT PARTICLES MAY DAMAGE PENSTOCK AND TURBINE!
CHECK REGULARLY AS NEEDED!
1
3 2
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Civil Works
70 GOOD & BAD of Mini Hydro Power
2.2.4 Forebay
Main elements and functioning principles of a forebay:
t " GPSFCBZ GVODUJPOT JO B TJNJMBS NBOOFS BT B TBOE USBQ UIF PX TMPXT EPXO TPsediments can settle down
t 5IFUSBOTJUJPOBUUIFCFHJOOJOHPGUIFGPSFCBZBOEUIFXJEUIPGUIFGPSFCBZBSFFTTFOUJBMGPSTMPXJOHEPXOUIFPXWFMPDJUZ
t 4FEJNFOUTDBOTFUUMFPVUJOTMPXPXJOHXBUFSPOMZt 5IFUSBTISBDLBUUIFFOEQSFWFOUTEFCSJTGSPNPXJOHJOUPUIFQFOTUPDLt 5IFGPSFCBZQSPWJEFTTVCNFSHFODFGPSUIFQFOTUPDLJOMFUUPQSFWFOUBJSGSPNFOUFSJOHt 5IF TQJMMXBZ BMMPXT FYDFTT BOE PPE PXT UP PXCBDL UP UIF SJWFS FTQFDJBMMZ VOEFS
rapid shut down conditions following load rejection
t 5IFVTIJOHHBUFJTFTTFOUJBMGPSDMFBOJOHUIFGPSFCBZPGTFEJNFOUTBTSFRVJSFE
River
Headrace
Spillway
Flushing gate
Penstock to power house
Trash rack
Forebay
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Civil Works
GOOD & BAD of Mini Hydro Power
Main elements of a forebay
The drawing shows a typical forebay which marks the transition between the open headrace channel and the penstock. The water level in the forebay determines the head which is available for power generation. The trash rack in the forebay and the forebay itself is the last QPJOU UP SFNPWFBOZUIJOHUIBUDPVMEEBNBHFUIF UVSCJOF GSPNUIFXBUFS TVDIBTPBUJOHdebris or sediment. Also it provides a controlled way of escape over the spillway for surplus water in case of a load rejection or when too much water enters the open channel part of the headrace.
Ventilation pipe Inlet gate
Penstock
Overflow channel
Flush gate
SpillwayHeadrace
Transition to forebayTrash rack
Service area
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Civil Works
72 GOOD & BAD of Mini Hydro Power
Forebay without sedimentation
How can I improve it?
t .BLFHSBEVBMUSBOTJUJPOXJUIBOBOHMFPGSBUJPPSMFTTt 1MBDFUIFUSBTISBDLPOUPQPGBTJMMBUUIFCPUUPNPGUIFGPSFCBZt *OTUBMMBVTIJOHHBUFBUUIFCPUUPNPGUIFGPSFCBZBOEDPOOFDUJUXJUIUIFTQJMMXBZt .BLF TQBDJOH XJEUI PG USBTI SBDL CBST EFQFOEFOU PO UVSCJOF NBOVGBDUVSFST
requirements
Why?
t "WPJEFEEJFTBOEEFBE[POFTJOUIFGPSFCBZt 'MPXBQQSPBDIJOHUIFUSBTISBDLTIPVMECFTUFBEZMJOFBS
t 8BMMTJMMXJMMIPMECBDLUIFTFUUMFEPVUTFEJNFOUTt 'MVTIJOHHBUFBMMPXTUPFNQUZBOEDMFBOUIFGPSFCBZ
Note:
SEDIMENT REACHING THE TURBINE CAN DAMAGE THE RUNNER!
Bottom sill is missing
Flushing gate is missing
Horizontal bars are difficult to clean
Overflow spillway NOT to the hillside!
Gradual transition would be better
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Civil Works
GOOD & BAD of Mini Hydro Power
Forebay with sedimentation basin
Why is this a good example?
t 'PSFCBZXJUITFEJNFOUBUJPONVTUCFXJEFSBOEEFFQFSUIBOUIFIFBESBDFt 8JEUIPGGPSFCBZTIPVMECFBUMFBTUUJNFTUIFXJEUIPGUIFIFBESBDFDIBOOFMt -FOHUIPGUSBOTJUJPOTIPVMECFBCPVUUJNFTUIFXJEUIPGIFBESBDFPSUIFBOHMFPGUIF
transition should be around 25 degrees (a ratio of 1:2)
t 4UPQMPHHSPPWFTBMMPXUIFJOTFSUJPOPGCPBSETMPHTUPCMPDLUIFPXXIFODMFBOJOHand repairing the forebay
Vent pipe of penstock
Inlet gate to penstock
Gate for flushing
Trash rack
min. 2x width of headrace
Width of headrace
Groove for stop logs
Spillway
Ratio 1:2
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75
Civil Works
GOOD & BAD of Mini Hydro Power
2.2.5 Trash Rack
Main design principles of a trash rack:
t 5IFBOHMFPGBUSBTISBDLUPUIFIPSJ[POUBMTIBMMCFUPt 5SBTISBDLTIPVMECFYFEUPUIFTJEFXBMMTBOEUPUIFTJMMXBMMBTXFMMCVUJOTVDIBXBZ
that the trash rack can be removed for service
t 6TF0/-:WFSUJDBMCBSTXIJDIDBOCFTVQQPSUFECZIPSJ[POUBMCSBDJOHBU UIFCBDL TPthat rack can be cleaned easily
t 5IFCBSTNVTUCFEFTJHOFE UPXJUITUBOE UIFXBUFSQSFTTVSFPG B DPNQMFUFMZ DMPHHFErack with maximum water level upstream and no water downstream
t 5IFTQBDFCFUXFFOCBSTTIPVMECFIBMGPGUIFTQBDFCFUXFFOUVSCJOFSVOOFSPSHVJEFvane blades, in accordance with the turbine manufacturer. Here are some examples:
$SPTTPXUVSCJOFFH5NN Pelton turbine: 0.5 times nozzle diameter
t 5SBTI SBDL TIBMM CF EJWJEFE JOUP TFDUJPOT TP UIBU JU DBO CF SFNPWFE SFQBJSFE BOEtransported more easily
t 1SPWJEFBTFSWJDFBSFBGPSFBTJFSDMFBOJOHJODMVEJOHBQMBUGPSNUPTUBOEPO
Service area (platform)Trash Rack
Flow
Penstock
20cm min. high sill (low wall)
Forebay
4 x DN
20cm
DN
h
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Civil Works
76 GOOD & BAD of Mini Hydro Power
Trash rack on top of a sill (low wall)
How can I improve it?
t 6TFUSBTISBDLTXJUIWFSUJDBMCBSTPOMZt 4QBDFCFUXFFOCBSTTIPVMECFIBMG UIFTJ[FPGBQBSUJDMFXIJDIDBONPWFUISPVHIUIF
turbine without doing any damage
t 1MBDFUSBTISBDLBUBOBOHMFPGBSPVOEUPUIFCPUUPNt 'JYUSBTISBDLXJUICPMUTUPUIFTJEFXBMMTBOEUPUIFCPUUPNXBMMoCVUJUTUJMMTIPVMECF
removable
t 'PSMBSHFSUSBTISBDLTEJWJEFJUJOTFQBSBUFTFDUJPOTt )FJHIUPGTJMMMPXXBMMCFBNJOJNVNPGDN
Why?
t 7FSUJDBMCBSTNBLFDMFBOJOHUIFUSBTISBDLFBTJFSt 5SBTISBDLQMBDFEBUBOJODMJOFEBOHMFXJMMOPUDMPHBTFBTJMZXJUIEFCSJTt "QMBDFUPTUBOEBTTFSWJDFBSFBXJMMNBLFUIFNBJOUFOBODFFBTJFS
Penstock inlet is too close to the bottom
Outlet drain should be at bottom level
Width not according to requirements
Angle should be 70
min. 20 cm
Sill (low wall or step)
Avoid horizontal bars
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77
Civil Works
GOOD & BAD of Mini Hydro Power
%FCSJTDBVTFTIFBEMPTTFTBOEPSSFEVDFTUIFXBUFSPXJOUPUIFQFOTUPDL
Why is this a good example?
t 5SBTISBDLJTNPVOUFEBUBOBOHMFPGBCPVUGSPNUIFIPSJ[POUBMt 5SBTISBDLJTYFEUPUIFXBMMTCVUJUTIPVMETUJMMCFSFNPWBCMFt 5IFUSBTISBDLIBTWFSUJDBMCBSTXIJDINBLFTJUFBTJFSUPDMFBOt 5IFHBQTCFUXFFOCBSTBQQFBS UJHIUFOPVHIUPLFFQEBNBHJOHEFCSJTBXBZ GSPNUIF
turbine
t -BSHFTFSWJDFBSFBBOEBQMBDFUPTUBOEGPSFBTZNBJOUFOBODFt %FCSJTDBOCFDMFBOFEBOEUFNQPSBSJMZTUPSFEJOUIFTFSWJDFBSFB
Trough for debrisService area
Use rake for easy cleaning
Trash rack at a good angle
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Civil Works
78 GOOD & BAD of Mini Hydro Power
4PNFCBETBNQMFToBWPJEUIFN
A too small open area causes head loss &
penstock inlet is not enough submerged
Horizontal support should be at the rear
side of the rack
Trash rack to be bolted & fixed to the side walls - not just leaning on them
The gaps are too narrow and rack is not fixed at an angle of about 70
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79
Civil Works
GOOD & BAD of Mini Hydro Power
4PNFHPPEFYBNQMFToEPMJLFUIJT
Rack properly fixed to the walls
Service area for maintenance
Trash rack fixed on top of a bottom sill or step, with
service opening
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Civil Works
80 GOOD & BAD of Mini Hydro Power
What must I do to keep system running well?
1 Remove all debris and rubbish a rake is a good tool for this job
2 Trough at the top end of the trash rack makes the removal of debris easiero store organic debris on a compost pile
Note:
DEBRIS MAY DAMAGE THE TURBINE!
CHECK AT LEAST TWICE A DAY AND EVEN MORE OFTEN DURING STORMS OR FLOODS!
1
2
Trough for debris removal
Service area
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81
Civil Works
GOOD & BAD of Mini Hydro Power
2.2.6 Spillway
This drawing shows an example of a forebay and a stepped spillway which allows excess XBUFSUPPXCBDLUPUIFSJWFSPWFSUIFTQJMMXBZXJUIPVUEPJOHEBNBHFUPUIFQFOTUPDLPSits supports. The steps in the spillway reduce the velocity of the water and cause energy dissipation. This is very important to prevent damage from the spill to the powerhouse and other structures.
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Civil Works
82 GOOD & BAD of Mini Hydro Power
8BUFSDBSSJFTIJHIFOFSHZXIFOPXJOHEPXOBTUFFQTMPQF
How can I improve it?
t #VJMEPCTUBDMFTJOUPUIFTQJMMXBZUPSFEVDFUIFWFMPDJUZBOEEJTTJQBUFUIFXBUFSTFOFSHZt *UXPVMEFWFOCFCFUUFS UPCVJMEESPQT JO UIFTQJMMXBZXIJDI JT UIFODBMMFEB TUFQQFE
spillway
Why?
t 5IF EZOBNJD GPSDF PGXBUFS JT WFSZ IJHIXIFO PXJOH EPXO B TUFFQ TMPQF t JU DPVMEdamage and destroy even concrete structures
Spillway and tailrace to the river
Overflow spillway needs drops
Power house
Penstock
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83
Civil Works
GOOD & BAD of Mini Hydro Power
Energy dissipation is happening at every step
Why is this a good example?
t "TUFQQFETQJMMXBZSFEVDFTUIFWFMPDJUZBOEEJTTJQBUFTUIFJOUIJTDBTFIBSNGVMFOFSHZof the water step by step
Multiple drops
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85
Civil Works
GOOD & BAD of Mini Hydro Power
2.2.7 Penstock and Support
Main design principles for a stable penstock:
t 4FUBODIPSCMPDLBUFBDIDIBOHFPGEJSFDUJPOoIPSJ[POUBMBOEWFSUJDBMoPGUIFQFOTUPDLt 4VQQPSUFBDIQJFDFPGQJQFXJUIBTMJEFCMPDLt 'BTUFOUIFQFOTUPDLUPUIFTVQQPSUTXJUITUFFMTUSBQTt &OTVSF UIBU BMM CMPDLT IBWF B TPMJE BOE TUBCMF GPVOEBUJPOXIJDI EFQFOET PO HSPVOE
material and slope
t #FGPSFQFOTUPDLFOUFSTQPXFSIPVTFUIFSFNVTUCFBUISVTUCMPDLUPBCTPSCBMMEZOBNJDwater forces in the pipe
t 1FOTUPDLJOMFUNVTUCFDNBCPWFCPUUPNJOWFSUBOEXBUFSEFQUIBCPWFJOMFUTIPVMEbe 4 times the diameter of the penstock pipe
Intake GateA thrust block is an anchor which is
used before the power house
Serrations (small grooves) ensure proper key between anchor and foundation
Slide Block
Expansion joint
Restrained
Vent
Pipe
Power house
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Civil Works
86 GOOD & BAD of Mini Hydro Power
Penstock must have solid supports at regular intervals
How can I improve it?
t 6TFDPODSFUFPSTUFFMTVQQPSUTFUPOBTPMJEGPVOEBUJPOt 5IFSFNVTUCFBOBODIPSCMPDLBUFWFSZIPSJ[POUBM BOEWFSUJDBMCFOE JO UIFQFOTUPDL
pipe
t 1JQFNVTUCFYFEUPUIFTVQQPSUTXJUITUFFMTUSBQT
Why?
t 5SFFTBOEUSVOLTSPUBOEMPTFUIFJSTUSFOHUIt "ODIPSCMPDLTSFTJTUUIFIZESBVMJDGPSDFTBUCFOETJOUIFQJQFt 8FBLPSVOTUBCMFTVQQPSUTNBZDBVTFUIFQFOTUPDLUPNPWFXIJDIDPVMEDBVTFVOEVF
stress on the pipe o risk of major failuret "CSFBLJOBIJHIQSFTTVSFQFOTUPDLDPVMEDBVTFTFSJPVTXBUFSEBNBHF
Note:
PVC PENSTOCKS HAVE TO BE COVERED TO AVOID PVC MATERIAL BECOMING BRITTLE AND EVENTUALLY FAILING!
A tree is NO pipe support
NO base for a solid support
Anchor block Is missing
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87
Civil Works
GOOD & BAD of Mini Hydro Power
The penstock pipe sections are well supported
Why is this a good example?
t &WFSZQJQFTFDUJPOJTXFMMTVQQPSUFEt 1JQFJTYFEUPUIFDPODSFUFTVQQPSUTXJUITUFFMTUSBQTt $PODSFUFJTUIFCFTUNBUFSJBMGPSQJQFTVQQPSUTt 1JQFJTBCPVUNFUFSBCPWFUIFHSPVOEt 1SPQFSUSFODIESBJOBHFo important for long-term stability of supports
Note:
STEEL PENSTOCKS REQUIRE EXPANSION JOINTS BETWEEN ANCHOR BLOCKS AND FOR SECTIONS LONGER THAN 30 m o INSTALL EXPANSION JOINTS DOWNSTREAM OF ANCHOR BLOCKS!
Penstock
Pipe supports regular spacing
Drainage of surface water
Steel strap
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Civil Works
88 GOOD & BAD of Mini Hydro Power
Expansion joint must be installed in penstock after each anchor block
How can I improve it?
t #VJMEBOFXBODIPSCMPDLXJUIBTPMJEGPVOEBUJPOt "GUFSFBDIBODIPSCMPDLUIFSFNVTUCFBOFYQBOTJPOKPJOUPOUIFQJQF
Why?
t *GUIFSFJTOPFYQBOTJPOKPJOUUIFQJQFDBOOPUBCTPSCUIFMPOHJUVEJOBMNPWFNFOUTPGUIFpipe due to hydraulic forces and temperature changes
t "CSFBLJOBIJHIQSFTTVSFQFOTUPDLDPVMEDBVTFTFSJPVTXBUFSEBNBHFBOEXBTIPVUthe supports and even damage the powerhouse
Note:
RISK OF FAILURE!
Missing expansion joint possibly caused
broken support
PenstockUnsolid foundation
Broken anchor block
-
89
Civil Works
GOOD & BAD of Mini Hydro Power
An anchor block with an adjacent expansion joint
Why is this a good example?
t 5IFBODIPSCMPDLBCTPSCTUIFXFJHIUBOEIZESBVMJDGPSDFTPGUIFQJQFTFDUJPOBCPWFUIFanchor block
t &YQBOTJPOKPJOUTBMMPXGPS MPOHJUVEJOBMNPWFNFOUTPGUIFQJQFTFDUJPOEPXOTUSFBNPGthe anchor block
t 1JQFDBOFYQBOEPSDPOUSBDUBTBSFTVMUPGUFNQFSBUVSFDIBOHFTBOEIZESBVMJDGPSDFT
Pipe support
Anchor block
Steel strap to fix the pipe to the support
Expansion joint
-
Civil Works
90 GOOD & BAD of Mini Hydro Power
Several examples of poorly installed penstocks
How can I improve it?
t %PQFSJPEJDJOTQFDUJPOBOENBJOUFOBODFUPOEBOEYQSPCMFNTt "EETUFFMTUSBQTUPYUIFQJQFUPUIFTVQQPSUTt 3FQMBDFQJQFTFDUJPOTXIFOQJQFJTMFBLJOHPSDSBDLFEt 6TFBOHFEUUJOHTGPSQJQFDPOOFDUJPOTt 3FQMBDFGBVMUZFYQBOTJPOKPJOUT
Why?
t -FBLJOHPSGBVMUZQJQFTBOEKPJOUTDPVMEDBVTFBCVSTUQJQFBOETFSJPVTXBUFSEBNBHFoNO electrical power generation would result
t 8BUFSJOUIFQPXFSIPVTFPSBUUIFUSBOTGPSNFSDBODBVTFFMFDUSJDBMTIPDLTt *NQSPQFSMZTVQQPSUFEBOEYFEQJQFDPVMEGBJMSFTVMUJOHJOMPTTPGQPXFSBOESFRVJSJOH
costly repairs
NOT a proper joint
Support is broken - strap is not fixed
Pipe sealed with tape
NO straps
-
91
Civil Works
GOOD & BAD of Mini Hydro Power
A well built and properly maintained penstock
Why is this a good example?
t 5IFSFBSFTVQQPSUTGPSFBDIQJQFTFDUJPOEVFUPUIFQJQFTIJHIXFJHIUt 4UFFMTUSBQTGBTUFOUIFQJQFUPUIFDPODSFUFTVQQPSUTt 5IFSFJTBEFRVBUFHSPVOEDMFBSBODFPGBCPVUDNt 5IFSFBSFOPTJHOTPGNPWFNFOUTEFGPSNBUJPOPSDSBDLTt 5IFQJQFJTXFMMQBJOUFEBTQSPUFDUJPOBHBJOTUDPSSPTJPOt (SBTTPUIFSWFHFUBUJPOBOEEJSUIBWFCFFODMFBSFEBXBZGSPNQFOTUPDL
Pipe supports
Steel straps
Penstock
-
Civil Works
92 GOOD & BAD of Mini Hydro Power
4PNFCBEFYBNQMFTPGQFOTUPDLTVQQPSUToUPCFBWPJEFE
Support leans on poor base
Base not well founded on solid ground
Cover is not sufficient
PVC penstock well covered
NO base for a support
-
93
Civil Works
GOOD & BAD of Mini Hydro Power
Some good example of penstock supports
-
Civil Works
94 GOOD & BAD of Mini Hydro Power
Penstock inlet gate without required ventilation pipe
How can I improve it?
t *OTUBMMBWFOUJMBUJPOQJQFJOUIFQFOTUPDLEPXOTUSFBNPGUIFHBUF
Why?
t 5IF WFOUJMBUJPO QJQF BMMPXT BJS UP FOUFS UIF QFOTUPDL XIFO UIF QFOTUPDL JT SBQJEMZemptied. Without ventilation pipe the penstock could easily be damaged by a vacuum collapse of the pipe
t *GQFOTUPDLJTFRVJQQFEXJUIBOJOMFUHBUFUIFSFNVTUCFBWFOUJMBUJPOQJQF
Note:
A PENSTOCK WITH INLET GATE REQUIRES A VENTILATION PIPE!
NO ventilation pipeInlet gate
NO service area for trash rack
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95
Civil Works
GOOD & BAD of Mini Hydro Power
Penstock inlet gate and ventilation pipe
Why is this a good example?
t 1FOTUPDLQJQFTXJUIBOJOMFUHBUFNVTUIBWFBWFOUJMBUJPOQJQFt %JBNFUFSPGWFOUJMBUJPOQJQFEFQFOETPOQFOTUPDLEJBNFUFS
Note:
THE VENTILATION PIPE PREVENTS A VACUUM COLLAPSE OF THE PENSTOCK PIPE WHEN IT IS EMPTIED!
Ventilation pipe Inlet gate
Penstock
Forebay with trash rack and spillway
Service area
-
Civil Works
96 GOOD & BAD of Mini Hydro Power
What must I do to keep system running well?
1 Check for rust and condition of paint clean and re-paint as needed
2 Check pipe supports and anchor blocks for deformation, settlings or any other movements repair cracks with cement grout
3 $IFDLUJHIUOFTTPGOVUTCPMUTPGBOHFTBOETUSBQToUJHIUFOBTOFFEFE4 Check all joints, especially expansion joints, for leaks fix if needed
5 Remove grass, shrubs and dirt do it regularly
Note:
CHECK PENSTOCK AT LEAST EVERY THREE MONTHS!
1
3
2
4
5
1
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97
Civil Works
GOOD & BAD of Mini Hydro Power
2.2.8 Power House and Tailrace
The drawing shows a typical setup for a small powerhouse and a short tailrace which takes the XBUFSCBDLUPUIFSJWFSPODFJUIBTPXOUISPVHIUIFUVSCJOF5IFQPXFSIPVTFNVTUDMFBSMZTJUXFMMQSPUFDUFEBOEBCPWFQPTTJCMFPPEXBUFSMFWFMTJOUIFSJWFSTPJUDBOOPUHFUEBNBHFEThe tailrace is a part of the hydraulic system of the MHP and needs to function well just like the headrace. It must not be blocked or full of vegetation or debris. Usually the tailrace is very short but there are also MHP with tailraces several hundred meters or even kilometres long. This depends on the specific situation or topography.
Tailrace
-
Civil Works
98 GOOD & BAD of Mini Hydro Power
This power house is NOT a safe place for valuable equipment
How can I improve it?
t 1BJOUUIFXBMMTBTXFMMBTUIFXPPEFOQBSUTMJLFXJOEPXTBOEEPPSt 'JYUIFSPPGt ,FFQUIFPPSUJEZt $MFBOUIFPVUTJEFXPSLJOHTQBDF
Why?
t 5IFQPXFSIPVTFQSPUFDUTDPTUMZNFDIBOJDBMFMFDUSJDBMFRVJQNFOUt *UQSFWFOUTBDDFTTCZVOBVUIPSJ[FEQFSTPOTt "EWFSTFXFBUIFSDPOEJUJPOTDPVMEEBNBHFUIFFRVJQNFOU
Broken roof and windows
Dirty walls and windows
-
99
Civil Works
GOOD & BAD of Mini Hydro Power
A well built and maintained power house located at a suitable place
Why is this a good example?
t "MMJNQPSUBOUFMFNFOUTIBWFCFFODPOTJEFSFEt "MMOFDFTTBSZGFBUVSFTIBWFCFFOJODMVEFEt 5IFCVJMEJOHJTXFMMNBJOUBJOFEBOENBLFTBOFBUJNQSFTTJPOt 5IFIPVTFJTXFMMBDDFTTJCMFXIJDIJTJNQPSUBOUQBSUJDVMBSMZEVSJOHOJHIUIPVST
Power house holds costly equipment
Penstock with anchor block and supports
Safe access for the operators
Tailrace to the river
-
Civil Works
100 GOOD & BAD of Mini Hydro Power
5IJTQPXFSIPVTFQSPWFE/05UPCFPPEQSPPG
How can I improve it?
t #VJME B SFUBJOJOH XBMM BSPVOE UIF CVJMEJOH BOE CBDLMM UIF BSFB UP QSPUFDU UIFGPVOEBUJPOTPGUIFQPXFSIPVTF5BLFDBSFUPOPUCMPDLUIFPXPGUIFSJWFSCZUIFXBMM
Why?
t 5IFSF JT DPTUMZ NFDIBOJDBM FMFDUSJDBM FRVJQNFOU JO UIF QPXFS IPVTF UIBU NVTU CFQSPUFDUFE&WFOXJUIBSFUBJOJOHXBMMUIJTQPXFSIPVTFJTOPUPPEQSPPGCFDBVTFJU JTlocated too low in the river. Waterproof doors and temporary sand bags can help possibly JODBTFPGBTNBMMFSPPE#FUUFSDMPTFUIFXJOEPXBOEEPPSPQFOJOHXJUIDPODSFUFBOECVJMEBOFXBDDFTTWJBUIFSPPG,FFQQVNQTSFBEZJOUIFQPXFSIPVTFJODBTFPGBPPEto protect the equipment
t "TUIFQJDUVSFJOUIFSJHIUDPSOFSTIPXTBTFWFSFPPEXIJDIPDDVSSFETIPSUMZCFGPSFcompletion of this book has caused serious damage unfortunately even to a second turbine which was installed at the same location
Step-up transformer for medium voltage transmission
Wall
Power house in the rivero NOT a good place !
-
101
Civil Works
GOOD & BAD of Mini Hydro Power
A well located and properly built power house
Why is this a good example?
t 5IFQPXFSIPVTFJTXFMMQSPUFDUFEBHBJOTUPPETJOUIFSJWFSCFDBVTFJUTJUTBCPWFPPEwater level
t 5IFXBUFSJOUIFUBJMSBDFSFUVSOTUPUIFSJWFSXJUIBTNBMMESPQBOEEPFTOPUFSPEFUIFriver bank
t 5IFQPXFSIPVTFJTBTPMJEBOEOFBUMPPLJOHTUSVDUVSF
Penstock
Tailrace
Retaining walls protect the power house area against
erosion and floods
-
Civil Works
102 GOOD & BAD of Mini Hydro Power
Pipe support does NOT replace the need for a thrust block
How can I improve it?
t #VJMEBDPODSFUFUISVTUCMPDLBSPVOEUIFQFOTUPDLt -FBWFBKPJOUCFUXFFOUIFCMPDLBOEUIFCVJMEJOHt *OTUBMMBOFYQBOTJPOKPJOUBIFBEVQTUSFBNPGUIFUISVTUCMPDL
Why?
t " UISVTUCMPDLBCTPSCT UIFQFOTUPDLTXFJHIUBOEIZESBVMJD GPSDFTPG UIFXBUFS JO UIFpenstock
t "OFYQBOTJPOKPJOUBCTPSCTQJQFFYQBOTJPOEVFUPUFNQFSBUVSFDIBOHFTBOEBMTPUIFhydraulic forces in the pipe between anchor blocks
Joint between house and pipe is
missing
Thrust block missing
Support does NOT replace a thrust
block
Power house
Penstock
-
103
Civil Works
GOOD & BAD of Mini Hydro Power
Solid thrust block prevents the penstock from moving
Why is this a good example?
t 5IFUISVTUCMPDLBTTVSFTUIBUUIFQFOTUPDLJTYFEBOEEPFTOPUNPWFBOEQVTIPSQVMMthe house wall
t *UJTCFUUFSJGUIFUISVTUCMPDLJTTFQBSBUFEGSPNUIFIPVTFt %SBJOBHFEJUDIFTBSPVOEUIFCVJMEJOHLFFQTVSGBDFXBUFSBXBZGSPNUIFQPXFSIPVTF
Power House
Penstock
Turbine
Power House
Trust block
Thrust block
-
Civil Works
104 GOOD & BAD of Mini Hydro Power
What must I do to keep system running well?
1 Keep tailrace clean and free of debris
2 Check for erosion in the river
Note:
ONLY FREE FLOW IN THE TAILRACE KEEPS THE TURBINE RUNNING!
CHECK AND CLEAN AS NEEDED!
1
2
-
Electro-Mechanical Equipment
105GOOD & BAD of Mini Hydro Power
3. Electro -MechanicalEquipment
3. Electro-MechanicalEquipment
-
Electro-Mechanical Equipment
106 GOOD & BAD of Mini Hydro Power
3.1 BASICS
Typical electro-mechanical elements of a Micro Hydro Power Plant
t 5VSCJOFt .FDIBOJDBMUSBOTNJTTJPOHFBSt (FOFSBUPSt 5VSCJOFDPOUSPMMFSt $POUSPMBOEQPXFSDBCJOFU
Automatic voltage regulator (AVR)
Generator
FlywheelMechanical transmission
Turbine
to Panel
-
Electro-Mechanical Equipment
107GOOD & BAD of Mini Hydro Power
What are the main challenges to set up these machines?
It is most important that the electro-mechanical components and their baseframe are sitting on a solid and stable foundation and that the shafts of all components are perfectly aligned as required.
GeneratorBelt drive in a cage
Adjustable steel base
Turbine
Bearings Coupling
-
Electro-Mechanical Equipment
108 GOOD & BAD of Mini Hydro Power
Perfectly aligned shafts are essential for good operation
What should be considered for good workmanship?
t 5IFJOTUBMMBUJPOPGUVSCJOFBOEHFOFSBUPSNVTUCFEPOFXJUIDBSFt .BLF TVSF UIBU UIF TIBGUT PG UVSCJOF BOE HFOFSBUPS BSF QFSGFDUMZ QBSBMMFM UP UIF
IPSJ[POUBMBOEUPUIFWFSUJDBMQMBOFt 5IJTQBSBMMFMBMJHONFOUJTWFSZJNQPSUBOUGPSBTNPPUIUSBOTNJTTJPOBOEMPOHFSMJGFUJNFt #FMUQVMMFZTSFRVJSFBYJBMBMJHONFOUt 5IFBEKVTUNFOUTPGUIFTIBGUTNVTUCFEPOFXJUIBMPUPGDBSFt 4VCGSBNFOFFETUPCFBEKVTUBCMFJOPSEFSUPBMMPXQSFDJTFBMJHONFOUt 'PSCFMUUJHIUFOJOHUIFTVCGSBNFTIPVMEBMXBZTCFNPWFEJOQBSBMMFMt .JTBMJHONFOUDBVTFTUSBOTNJTTJPOQSPCMFNTUIFSFXJMMCFBMPUPGXFBSBOEUFBSPOCFMU
and bearings they may have to be replaced much sooner
t $BSF TIPVME CF UBLFO EVSJOH DBTUJOH PG UIF DPODSFUF GPVOEBUJPO UP HFU JU QFSGFDUMZhorizontal to make adjustments of the equipment bases at a later stage easier
Turbine Shaft
BearingRunner TURBINE
Pulley
H = Horizontal deviation
V = Vertical deviation
Slide rails
Inter line coupling
Axial alignment
Puley
Subframe
GENERATOR
Gen. Shaft
-
Electro-Mechanical Equipment
109GOOD & BAD of Mini Hydro Power
Belt driven Generator
Direct driven Generator
TURBINE
Shafts must be on the same axis
Induction motor and gearbox used as alternator
Gearbox
In-line coupling
Turbine runner
Misalignments
Both shafts must be horizontal and paralell to each other
Both pulleys must be in the same plane
GeneratorTurbine
-
Electro-Mechanical Equipment
111GOOD & BAD of Mini Hydro Power
3.2 INDIVIDUAL COMPONENTS
3.2.1 Turbine
.BJOFMFNFOUTPGBDSPTTPXUVSCJOF
Note:
THE GUIDE VANE REGULATES THE FLOW TO THE TURBINE!
Runner blades
Guide vane
-
Electro-Mechanical Equipment
112 GOOD & BAD of Mini Hydro Power
Incorrect size of washers
How can I improve it?
t 6TFUIFDPSSFDUTJ[FPGXBTIFSTJOUIJTDBTFMBSHFS
t 5IFFEHFTPGUIFXBTIFSTNVTUCFQBSBMMFMUPUIFCPMUTMPUBOENVTUDPWFSJUDPNQMFUFMZ
Why?
t #PMUTDPOOFDUUIFUVSCJOFUPUIFTUFFMCBTFBOEYJUTQPTJUJPOt 5IFXBTIFSTEJTUSJCVUFUIFMPBEFWFOMZPOUIFTUFFMCBTF
Note:
WASHER SIZE SHOULD BE TWICE THE DIAMETER OF THE HOLE!
BOLT SLOTS ALLOW A PRECISE ALIGNMENT OF THE EQUIPMENT!
Washers should be of this size
Bolt slot not covered and washers are too
small
Bolt slots
-
Electro-Mechanical Equipment
113GOOD & BAD of Mini Hydro Power
Why is this a good example?
t 5IFXBTIFSTIBWFDPSSFDUEJNFOTJPOTBOEBSFDFOUFSFEUPUIFIPMFt 5IFUBQQFSXBTIFS JTOFDFTTBSZ UPDPNQFOTBUF UIFTMPQFPG UIFTUFFM TFDUJPOXJUI UIF
horizontal steel base
t 4DSFXTIBWFUPCFJOTUBMMFEWFSUJDBMMZ
Steel base, horizontally
Correct size
Tapper washer compensates inclination
Inclination
Turbine
Turbine housing
BaseTapper washer
-
Electro-Mechanical Equipment
114 GOOD & BAD of Mini Hydro Power
Clogged runner and guide vanes
How can I improve it?
t 1SFWFOUEFCSJTGSPNHFUUJOHJOUPUIFQFOTUPDLCZJOTUBMMJOHBOFUSBTISBDLBDDPSEJOHUPthe requirements of the turbine manufacturer
t $MFBOBOENBJOUBJOUIFUSBTISBDLSFHVMBSMZ
Why?
t %FCSJTJOUIFUVSCJOFCMBEFTJOJUJBMMZSFEVDFTUIFQFSGPSNBODFPGUIFUVSCJOFCVUeventually will clog and damage the turbine
t &TQFDJBMMZ'SBODJTBOEQSPQFMMFSUVSCJOFTBSFTVTDFQUJWFUPHFUCMPDLFECZEFCSJT
Debris between the guide vanes and runner blades
-
Electro-Mechanical Equipment
115GOOD & BAD of Mini Hydro Power
A turbine in good condition thanks to a functional sand trap and trash rack
Why is this a good example?
t 5IFQFSGPSNBODFPGUIFUVSCJOFJTOPUJOVFODFECZEFCSJTt 5IF USBTI SBDL JT CVJMU BDDPSEJOH UP UIF SFDPNNFOEBUJPO PG UIF UVSCJOF TVQQMJFS BOE
keeps the turbine clean
t 5IBOLTUPBTBOEUSBQOPBCSBTJPOJTWJTJCMFPOUIFUVSCJOFSVOOFS
Note:
PROTECT THE TURBINE AND IT WILL KEEP RUNNING FOR A LONG TIME!
CLEAN TRASH RACK AND SAND TRAP REGULARLY!
No debris all clean
-
Electro-Mechanical Equipment
117GOOD & BAD of Mini Hydro Power
3.2.2 Main Elements of a Generator
The drawing depicts a synchronous generator with an AVR (Automatic Voltage Regulator). In island mode, the AVR controls the generator voltage which is the system voltage as well. In grid-connected mode, the AVR is not able to change the system voltage but by adjusting the excitation current it can determine the reactive power characteristics. Asynchronous generators do not have an AVR.
Ventilation gratingShaft of generator
connected with pulley
AVRCable in ducts to
panel
-
Electro-Mechanical Equipment
118 GOOD & BAD of Mini Hydro Power
Generator and AVR in bad condition
How can I improve it?
t 3FQMBDFBMMNJTTJOHQBSUTPGUIFHFOFSBUPSBOE"73t .BLFQSPQFSDBCMFDPOOFDUJPOTJOBDDPSEBODFXJUITBGFUZSFHVMBUJPOTt 1PXFSDBCMFNVTUCFMBJEJOBEVDUt $POOFDUHFOFSBUPSBOEDPOUSPMMFSUPBOFBSUIJOHTZTUFNt 5SBOTNJTTJPOCFMUNVTUCFQSPUFDUFEXJUIBDBHF
Why?
t 5IF QSFTFODF PG VOUSBJOFE QFSTPOT JO UIF QPXFSIPVTF JT QPTTJCMF 5IFZ NVTU CFprotected from the dangers of electricity and mechanical power.
t 4BGFUZSFHVMBUJPOTBMXBZTNBLFTFOTFBOEIBWFBSFBTPOUIFZIFMQUPQSFWFOUBDDJEFOUTand injuries
t (PPEBOEDPOTDJFOUJPVTPQFSBUJPOBOENBJOUFOBODFXPSLXJMMMFBEUPHPPEPQFSBUJPO
AVR dismantled
Power cable not protected
Belt without cover
Very messy cable connections
Protection missing
-
Electro-Mechanical Equipment
119GOOD & BAD of Mini Hydro Power
Generator well installed
Why is this a good example?
t 5IFFRVJQNFOUJTJOTUBMMFEJOBDDPSEBODFXJUITBGFUZSFHVMBUJPOTt 1PXFSDBCMFJTQSPUFDUFECZBFYJCMFQJQFt (FOFSBUPSBOEDPOUSPMMFSBSFDPOOFDUFEUPUIFFBSUIJOHTZTUFNt 5IFCFMUJTQSPUFDUFEXJUIBDPWFSt 5IFSFJTFOPVHITQBDFUPTIJGUUIFHFOFSBUPSJOUPUIFSJHIUQPTJUJPO5IFCFMUDBOCF
tightened by moving it on the sledge on the frame
t 5IFPPSJTDMFBOBMMPXJOHUPEFUFDUXBUFSMFBLBHFTPUIFSJSSFHVMBSJUJFTJNNFEJBUFMZ
AVR
Well protected power cable
Earthing connection
Generator
Belt cover
Adjustment screws
Sledge
-
3.2.3 Panel, Controller and Ballast
A safe place for all electrical devices
The control cubicle provides a safe place, dry and free of dust, for the electrical devices and also protects people working in the powerhouse from electrical shocks.
-
Electro-Mechanical Equipment
122 GOOD & BAD of Mini Hydro Power
Bad example of wiring and electric components
How can I improve it?
t .PVOUFMFDUSJDDPNQPOFOUTBOEXJSJOHJOBXFMMBSSBOHFETDIFNFt &MFDUSJDBMDPNQPOFOUTNVTUCFJOTUBMMFEJOBMPDLBCMFNFUBMDBTFt 1SFWFOU QVCMJD BDDFTT UP FMFDUSJD DPNQPOFOUT XJSJOH o JODMVEJOH BDDFTT GPS BOJNBMT
which can bite away the insulation of cables
Why?
t *NQSPQFSMZCVJMUQBOFMTBSFBQPUFOUJBMTPVSDFGPSUFDIOJDBMGBJMVSFTt &WFOFYQFSUTDBOVOEFSTUBOEBOEUIFSFBGUFSYBTZTUFNPOMZXIFOJUJTXFMMBSSBOHFEt #BSFXJSFTBSFEBOHFSPVT
Note:
RISK OF INJURY & DEATH!
Alignment of cables and components is confusing
Wires are not insulated
Mouse in panel
Boxes are not covered
-
Electro-Mechanical Equipment
123GOOD & BAD of Mini Hydro Power
Example of a well arranged control cubicle
Why is this a good example?
t $MFBSBSSBOHFNFOUPGBMMDPNQPOFOUTNBLFTNBJOUFOBODFTJNQMFBOEGBTUt $BCMFTBOEEFWJDFTBSFQSPQFSMZMBCFMFEt 3FQBJSTBSFRVJDLBOEFBTZUPEPt 8PSLJOHPOUIFDVCJDMFJTTBGFS
Note:
DURING OPERATION THE PANEL MUST BE CLOSED AND SHOULD BE LOCKED!
All cables are labeled
Panel of control cubicle
All elements are well arranged
-
Electro-Mechanical Equipment
124 GOOD & BAD of Mini Hydro Power
Unprotected ballast presents a real hazard
How can I improve it?
t 3FJOTUBMMCBMMBTUBUBXFMMWFOUJMBUFEQMBDFt "UUBDICBMMBTUIJHIFSoPVUPGSFBDIPGQFPQMFt .PVOUBTBGFUZDBHFBSPVOEUIFCBMMBTUt *OTUBMMBIFBUTIJFMEBHBJOTUUIFXPPEFOXBMMBOEDFJMJOHCPBSET
Why?
t )PUCBMMBTUJTBSFIB[BSEFTQFDJBMMZGPSXPPEFOCPBSETt 1MBTUJDDBCMFDPBUJOHTNBZNFMUt *GUIFCBMMBTUJTJOTUBMMFEUPPMPXTPNFCPEZNBZUPVDIJUBOEHFUCVSOFE
Note:
RISK OF INJURY!
Never touch the glowing rods
Wires are not protected against contact risk of
electric shock
Ventilation
-
Electro-Mechanical Equipment
125GOOD & BAD of Mini Hydro Power
Well protected ballast at outer wall of the power house
Why is this a good example?
t 5IFSPPGQSPUFDUTUIFCBMMBTUJOTUBMMBUJPOBHBJOTUSBJOt #BMMBTUJTXFMMWFOUJMBUFEt 5IFPVUFSDBHFQSFWFOUTBDDFTTCZVOBVUIPSJ[FEQFSTPOT
Note:
IN CASE OF LOW LOAD IN THE VILLAGE (WITH MOST APPLIANCES SWITCHED OFF) THE CONTROLLER DIVERTS ELECTRICITY TO THE BALLAST WHERE IT IS CONVERTED TO HEAT!
RODS ARE GLOWING HOT!
Outer cage
Protected and shaded by roof
Inner cage
-
Electro-Mechanical Equipment
126 GOOD & BAD of Mini Hydro Power
The distance between ceiling and the top edge of ballast must be at least 50 cm
How can I improve it?
t *OTUBMMCBMMBTUMPXFSPSJGUIBUJTOPUQPTTJCMFPVUTJEFPGUIFQPXFSIPVTFt 1SPUFDUUIFCBMMBTUXJUIBTBGFUZDBHFt 1SPWJEFWFOUJMBUJPOGPSUIFHMPXJOHSPET
Why?
t *GUIFFMFDUSJDJUZEFNBOEJTMPXUIFFYDFTTFOFSHZJTTFOUUPUIFCBMMBTU5IFSPETHFUWFSZhot and enough space to the roof plus a good ventilation is required to convey the heat
Note:
RISK OF FIRE!
Ceiling
Distance too short
-
Electro-Mechanical Equipment
127GOOD & BAD of Mini Hydro Power
A good installation of ballast
Why is this a good example?
t #BMMBTUJTXFMMQSPUFDUFEJOBTUFFMDBHFt #BMMBTUJTQSPQFSMZWFOUJMBUFEBTJUHFUTWFSZIPUt *OTUBMMBUJPOVOEFSUIFSPPGJTBHPPESBJOQSPUFDUJPOt 5IFXJSJOHUPUIFCBMMBTUJTSVOUISPVHIEVDUTt 6OBVUIPSJ[FEQFSTPOT IBWFOP BDDFTT UP UIFCBMMBTU BOE DPVME OPU CFCVSOFECZ UIF
glowing rods
Note:
CABLE DUCTS SHOULD BE GUIDED INSIDE THE CAGE TO PREVENT DAMAGE OF THE CABLES!
IF THESE CABLES ARE INTERRUPTED THE TURBINE CANNOT BE CONTROLLED ANYMORE!
Penstock
Power cable ducts
Cable duct should be guided inside the cage
Ballast in a cageRoof
-
Electro-Mechanical Equipment
128 GOOD & BAD of Mini Hydro Power
What must I do