COMPONENTS OF HYDROPOWER PROJECTS&DESIGNS

COMPONENTS OF HYDRO POWER PROJECT

CIVIL HYDRO ELECTRICAL & MECHANICAL MECHANICAL

CIVIL COMPONENTSESSENTIAL NON-ESSENTIAL

ESSENTIAL CIVIL COMPONENTS

DIVERSION STRUCTURES WATER CONDUCTOR SYSTEM POWERHOUSE TAILRACE SYSTEM

DIVERSION STRUCTURESDAMConcreteRock fillEarthenArchButtressCFRD(Concrete Faced Rock fill Dam)RCC Dam(Roller Compacted Concrete Dam)

DIVERSION STRUCTURESSPILLWAYOgeeChuteSide ChannelMorning gloryTunnelUnder sluices

DIVERSION STRUCTURESENERGY DISSIPATION ARRANGEMENTSStilling BasinsSki-jump buckets ( with or without plunge pools)Roller bucketsTEMEPORARY DIVERSION STRUCTURESDiversion ChannelsDiversion tunnelsCoffer Dams

DIVERSION STRUCTURES

BARRAGESWEIRSBroad crested weirTrench weir

WATER CONDUCTOR SYSTEMINTAKEHEAD REGULATORSDESILTING BASIN ( In open system)DESILTING CHAMBERS(In underground system)POWER CHANNEL

WATER CONDUCTOR SYSTEMHEAD RACE TUNNELCut & Cover SectionsAditsFOREBAYSURGE TANKSURGE SHAFTSURPLUS ESCAPE

WATER CONDUCTOR SYSTEMCROSS DRAINAGE WORKSAqueductsSiphon AqueductsSuper PassagesLevel CrossingsPENSTOCKS ( In open system)PRESSURE SHAFTS ( In under ground system)

POWERHOUSESURFACEUNDERGROUNDSEMI-UNDERGROUNDSHAFT

OVERALL DIMENSIONS OF POWERHOUSE L = Ls + K + X + N x Unit spacing WhereLs=length of service bayK=space required for crane to handle the last unitX=wall thicknessN=number of units.

TAIL RACE SYSTEMTAIL RACE CHANNELTAIL RACE TUNNELOUT FALL STRUCTURE

NON-ESSENTIAL CIVIL STRUCTURESLOG BOOMSLOG CHUTESFISH LADDER/PASSInfrastructure works

HYDROMECHANICAL COMPONENTSGATESRadial/SectorVertical LiftDrum typeStop logBulkheadVALVESButterflySphericalPENSTOCKS

ELECTRO-MECHANICAL COMPONENTS Turbine,scroll case & draft tubeGenerator (shaft,stator &rotor)Electrically operated traveling (EOT) craneMain inlet valve (MIV)LightingHeating, ventilation & air conditioning (HVAC)Oil handling unit (OHU)

ELECTRO-MECHANICAL COMPONENTSCablesControls & monitoringStation service transformer (SST)Generator step-up transformer (GSU)Unit auxiliary transformer(UAT)Bus barFire fightingDewatering system

ELECTRO-MECHANICAL COMPONENTS

Cooling water system Drainage systemBattery systemLiftsDG setCommunications Public address system

SWITCHYARD/G.I.SLightening Arrestors (LA)Circuit Breakers (CB)Current Transformers (CT)IsolatorsGantriesCable Ducts

SWITCHYARD/G.I.SBus DuctsPotential Transformers (PT)Shunt ReactorsPower Line Communication Carriers (PLCC)Wave Traps (WT)

FIGURE-1

POWER CHANNEL DEVELOPMENTFALLDIVERSION STUCTURE

POWER INTAKETAIL RACE POOLRIVERPOWER CHANNELFOREBAYPENSTOCKPOWER HOUSEFIGURE-2

POWER TUNNEL DEVELOPMENTFALLDIVERSION STUCTURE

POWER INTAKEHEAD RACE TUNNELTAIL RACE POOLPOWER HOUSERIVERSURGE SHAFTFIGURE-3

POWER HOUSESPILLWAYRIVERDAM TOE DEVELOPMENTDAM TOP ROADTAIL RACE CHANNELRESERVOIRFIGURE-4

ACCESS SHAFTDAMRIVERSURGE CHAMBERTAIL RACE TUNNELUNDERGROUND MACHINE HALLUPSTREAM STATION ARRANGEMENT(SWEDISH SYSTEM)FIGURE-5

DOWNSTREAM STATION ARRANGEMENT(SWISS TYPE)SURGE TANKACCESS GALLERYVALVE GALLERYUNDERGROUND MACHINE HALLACCESSTUNNELTAILRACE TUNNELPRESSURE SHAFTDAMPRESSURE TUNNELFIGURE-6

SURGE TANKTAIL RACE TUNNEL SURGE CHAMBERUNDERGROUND MACHINE HALLSURGE TANKINTERMEDIATE LOCATION OF STATION(ITALIAN ARRANGEMENT)FIGURE-7

DIAGONAL TUNNEL ALIGNMENT WITH AIR-CUSHION SURGE TANK (NORWEGIAN SOLUTION)FIGURE-8

RESERVOIRPRESSURE TUNNELPENSTOCKSURGE TANKSTEADY STATEHYDROSTATIC LEVELUNSTEADY UPSURGESURGE TANK SYSTEMFIGURE-1

PRESSURE TUNNELPRESSURE SHAFTEXCAVATED SURGE TANKTURBINETAILRACEMIN SURGE LEVELINTAKESURGE TANKMAX SURGE LEVELMAIN INLET VALVEFIGURE-9GATE GROOVESTEADY STATE LEVELRESERVOIR

RESERVOIRHIGH GRADIENT PENSTOCKSURGE TANKFREE STANDING SURGE TANKVALVETURBINETAILRACEINTAKELOW GRADIENT PENSTOCKDAMFIGURE-10

U/S AND D/S SURGE TANK SYSTEMUNDERGROUND POWER HOUSEAIR VENTDOWNSTREAM SURGE SHAFTPRESSURE SHAFTSTEADY STATE LEVELUPSTREAM SURGE SHAFTTAILRACE TUNNELHYDROSTATIC LEVELLOW PRESSURE CONDUITFIGURE-11RESER-VOIR

DESIGNS ASPECTS DAMS

SURGE TANK

POWER HOUSE

SELECTION OF TURBINE

ACCORDING TO USE 1. Storage Dam e.g. Gravity Dams, Rockfill Dam, Earth Dam, Arch Dam, Buttress Dam etc.2. Diversion Dam e.g.Weir, Barrage3. Detention Dam e.g. Dike, Water spreading Dam, Debris DamACCORDING TO HYDRAULIC DESIGN 1. Overflow Dams e.g. Spillway2. Non-overflow Dams e.g. Gravity Dam, Rockfill Dam, Earth Dam, Arch Dam, Buttress Dam etc.

ACCORDING TO MATERIAL1. Rigid Dams e.g. Gravity Dams, Arch Dam, Buttress Dam, Steel Dam, Timber Dam etc. 2. Non Rigid Dams e.g. Rockfill Dam, Earth Dam Classification of Dams DAMS

Selection of Dam Type

TOPOGRAPHYFOUNDATIONSITE FOR SPILLWAYAVAILABILITY OF MATERIALRESERVOIR & CATCHMENT AREA ADEQUATE STORAGE CAPACITY AREA OF SUMERGENCE WATER TIGHTNESS OF RESERVOIR SEDIMENTATION DEEP RESERVOIRCOMMUNICATIONLOCALITY/ SURROUNDINGSLENGTH & HEIGHT OF DAMLIFE OF DAMROADWAY

1. TOPOGRAPHY

a) Arch dam:Narrow V shaped valley with sound Abutments

b) Gravity Dam: Moderately wide V shaped valley with sound bed rock.

c) Rockfill dam:Plain & wide valley and alluvial soil or Boulders in the bed.Selection of Dam Type

2. GEOLOGY / FOUDATIONa) Rock foundation- Any type of Damb) Gravel & Coarse Sand - Earth & Rockfill Dam c) Fine Sand & Silt - Earth Damsd) Clay foundation - Not suitable Selection of Dam Type

Concrete Gravity DamDefinition:-A dam constructed of concrete or masonry that relies on its own weight for stability is called Gravity Dam.Gravity dams are dams which resist the horizontal thrust of the water entirely by their own weight.

FOUNDATION-NON OVERFLOW PORTION-OVERFLOW PORTION-D/S WORKS-DRAINAGE GALLERIES-UNDER SLUICES-SPECIAL SILT EXCLUSION ARRANGEMENTS-INTAKE-GATES-HOISTING ARRANGEMENTS- ROPE DRUM- HYDRAULIC-BRIDGE-INSTRUMENTS AND THEIR OBSERVATION ETC.Components of Concrete Dam

Assumptions made while establishing stability of a gravity dam:

1.DAM IS MADE OF INDIVIDUAL TRANSVERSE ELEMENTS EACH OF WHICH CARRIES ITS LOADS TO THE FOUNDATION WITHOUT TRANSFER OF LOAD TO ADJACENT BLOCKS.

2.THE VERTICAL STRESS VARIES LINEARLY FROM U/S FACE TO D/S FACE ON ANY HORIZONTAL SECTION.

Requirement for Stability

a.THE DAM SHALL BE SAFE AGAINST SLIDING ON ANY PLANE WITHIN THE DAM AND AT THE FOUNDATION.

b.THE DAM SHALL BE SAFE AGAINST OVERTURNING AT ANY PLANE WITHIN THE DAM AND AT THE BASE.

c.THE SAFE UNIT STRESSES IN THE CONCRETE OF DAM OR IN FOUNDATION MATERIAL SHALL NOT BE EXCEEDED.

Forces considered for Stability Analysis

1.RESERVOIR AND TAIL WATER LOADS

2.UPLIFT PRESSURE

3.EARTHQUAKE

4.EARTH AND SILT PRESSURES

5.DEAD LOAD

6.ICE PRESSURE

7.WIND PRESSURE

8.WAVE PRESSURE

9.THERMAL LOADS

Load Combination

A. Load Combination A (Construction Condition)- Dam completed but no water in reservoir and no tail water.B. Load Combination B (Normal Operating Condition)- Reservoir at maximum flood pool elevation, all gates open, tail water at flood elevation, ormal uplift and silt (if applicable)C. Load Combination C (Flood Discharge Condition)D. Load Combination D - Combination A with earthquakeE. Load Combination E - Combination B with earthquake but no ice.F. Load Combination F- Combination C but extreme uplift (drains inoperative)G. Load Combination G - combination E, but with extreme uplift (drains inoperative)

Partial Safety factors against SlidingLoadingF Fc

A,B,C1.53.6D,E1.22.4F,G1.01.2

(W-U) tan / F + CA/Fc.F . = ------------------------------------------------------ = 1

PF = Factor of safety against slidingW = total mass of damU = total uplift force tan = Coefficient of internal friction of materialC = Cohesion of the material at the plane consideredA = Area under consideration for cohesion F = Partial FOS in respect of friction Fc = Partial FOS in respect of CohesionP = Total horizontal force

Permissible tensile stress in Concrete

Load CombinationPermissible tensile stress

B0C0.01 fcE0.02 fcF0.02 fcG0.04 fc

Where fc is the cube compressive strength of Concrete

SURGE TANK

Functions of Surge TankReduces the water hammer pressureReduces conduit length subjected to water hammerImproves stability and turbine governorIt acts as a small reservoir which can accept the refused discharge and also meet the immediate requirement of water

Types of Surge Tank a) According to the material of constructionb) According to location relative to terrainc)According to location relative to power housed)According to hydraulic designe) Special surge tanks (Air Cushion Chambers)

CONCRETE SURGE TANKSSTEEL SURGE TANKS

Types of Surge TankAccording to the material of construction

Types of Surge Tank

According to location relative to terrainEXCAVATED SURGE SHAFTFREE STANDING SURGE TANK

Types of Surge TankAccording to location to Power UPSTREAM SURGE TANKDOWNSTREAM SURGE TANK

Types of Surge TankAccording to Hydraulic design

SIMPLE SURGE TANKRESTRICTED ORIFICE SURGE TANKDIFFERENTIAL SURGE TANKSURGE TANK WITH EXPANSION CHAMBERMULTIPLE SURGE TANK

SIMPLE SURGE TANKThese tanks are cylindrical in shape interposed betweenpenstock and pressure shaft.They may be;

UNDERGROUND SHAFTS OPEN AT THE TOPUNDERGROUND CYLINDRICAL CAVITY CHAMBERSOVERGROUND BUILT UP STRUCTURES IN RCC

RESTRICTED ORIFICE SURGE TANKThese tanks are modification of simple surge tank with an orifice of an considerably smaller diameter installed between the surge tank and the conduitInvolves considerable headloss due to throttlingRestricts max & min surge levels by dampening of surge oscillations

DIFFERENTIAL SURGE TANKIt has an additional internal riser pipe provided with annular ports opening into the outer surge shaft:The head building function is achieved through the riser pipeThe storage function is achieved through the outer shaft

Factors affecting the layout of Surge-Shaft

Various components of the Water Conductor SystemDischarge through the Water Conductor SystemTransient flow conditions in the Water Conductor SystemLength of the Water Conductor SystemTurbo-generator and relief-valve mechanismGround topography and Geology

Design Considerations for Surge Tanks

Surge Tanks should be Hydraulically & Mechanically stable and most economical:Location of Surge TankDampening of load variation in the Power SystemMaximum & Minimum surge levelsTopographyProvision to avoid erosion of lining due to pressure variations

DESIGN CONDITIONSThe surge tank shall be designed to accommodate the maximum and minimum water levels under worst condition:-The maximum upsurge level in the surge tank The minimum down surge level in the surge tank

POWER HOUSE L - SECTION

DECIDING THE POWER HOUSE LAYOUTDepending upon the topography and geology of the area power house can be located on surface or underground or as a semi underground power house.

Surface power houseUnderground power houseSemi underground or shaft power house

FACTORS INFLUENCING THE LAYOUT OF A HYDROPOWER STATIONCivil engineering considerationsDimensioning and design of electrical and mechanical equipments and accessoriesRequirement of spaces, clearances and areas for efficient operation and maintenance of power station.

POWER HOUSE

POWER HOUSE BUILDING CONSISTS OF THREE MAIN AREAS NAMELY

Machine Hall/Unit BayErection/Service BayControl Room/Auxiliary Bay

OVERALL DIMENSIONS OF POWERHOUSE For working out the Powerhouse dimensions, generator diameter, its weight, weight of rotor and the crane capacity including the crane span are required. Based on data collected from various Powerhouses, some curves and empirical formulae are available to determine the above dimensions and weights depending upon the speed, the installed capacity and the net head. Overall dimensions of the Powerhouse are thus worked out by fixing the unit spacing.

MACHINE HALLDepending upon structures, Machine Hall or Unit Bay can further be divided into three main subdivisions.

SUB STRUCTUREThis is the main foundation member of the power house which contains draft tube, draft tube elbow and cone, the foundation gallery and the sump.

INTERMEDIATE STRUCTUREIt is main part of the machine hall containing the spiral case, foundation for stator and rotor, turbine floor etc.

SUPER STRUCTUREPart of machine hall above the generator floor containing columns supporting EOT crane, roof and the wall is related as super structure.

SELECTION OF TYPE OF TURBINEHeads and discharges are the major criteria for the selection of turbines. For low to medium heads, Kaplan turbines are recommended: for medium to high heads having moderate discharge, Francis turbines are recommended, for very high heads, Pelton turbines are favored.

USBR recommends the selection of turbine as under: HeadType of Turbine18m or lessKaplan turbine 18 to 300mFrancis turbine 300m and abovePelton turbine

FACTOR INFLUENCING SELECTION OF TURBINEFrancis turbine requires less space and operate at higher running speed.

Hydraulically Francis turbine is more favourable because it can utilise the head down to the lowest tail water level, whereas impulse turbine has to be set up with a clearance of few meters above TWL.

Because of lower setting Francis turbine requires more excavation works.

Francis turbine involves extensive dismantling for replacement of worn out labyrinth, runners, guide vane etc. Whereas replacement is easy in case of impulse turbine.

Thus, the choice in each case is based on technical, economical and operative requirements including transportation limits.

PRELIMINARY DIMENSIONING OF THE POWER HOUSE SHALL INTER ALIA INCLUDE

Calculating specific speed and synchronous speed of turbine.Calculating the discharge diameter.Fixing the turbine settingCalculating the spiral case dimensionsCalculating the draft tube dimensionsFixing the height and weight measures i.e. crane span, crane rail height, generator diameter & weight, weight of rotor and crane capacity.Finalizing overall dimensions of the power house.

BASIC DATA REQUIRED SHALL INCLUDEMaximum water level (MWL) in the reservoir Full reservoir level (FRL)Minimum draw down level (MDDL)Average tail water level Minimum tail water levelAverage altitude of the siteMaximum temperature of waterNumber of units to be installedTotal anticipated installed capacityRestrictions regarding setting of turbines.

DEFINITIONSMaximum Head : The maximum head is defined as the difference between maximum reservoir level without spillway discharge and the minimum tail water level with one unit operating deducting the head losses.

Minimum Head: The minimum head is the difference between minimum draw down level and the minimum tail water level.

Design Head: The design head is defined as the head at which the peak efficiency of the turbine is developed at a rated speed and is calculated as under:

Design Head = 2/3 (Maximum head Minimum head) + Minimum head

NUMBER OF UNITS The unit cost per kilowatt in a hydroelectric installation decreases with lesser number of units. However, to meet large variation of loads and ensure operation efficiency multi unit plants have to be provided. In fact, during lower discharges in the river, 1 or 2 units are taken out for maintenance and repair.

Other equipment such as cranes, oil handling system, compressed air system, etc. of smaller size are required in multi unit installation. On the other hand, single unit installation have lower operating and maintenance cost, but the cost of service equipment as well as lesser energy generation due to break downs have to be borne. As such a careful system study has to be conducted before deciding the size and the number of the units.

LAYOUT OF SOME OF THE IMPORTANT HYDROELECTRIC PROJECTS OF NHPC

BAIRA SIUL H.E. PROJECT

LOKTAK H.E. PROJECT

SALAL H.E. PROJECT

TANAKPUR H.E. PROJECT

CHAMERA H.E. PROJECT

URI H.E. PROJECT

RANGIT H.E. PROJECT

DULHASTI H.E. PROJECT

DHAULIGANGA H.E. PROJECT

TEESTA H.E. PROJECT STAGE-V

LOKTAK D/S H.E. PROJECT

PARBATI H.E. PROJECT STAGE-II

SOME PHOTOGRAPHS/PICTURESOF THE IMPORTANT HYDROELECTRIC STRUCTURES/COMPONENTS

RIVER DIVERSION-TEHRI

EARTHEN DAM WITH CONCRETE SPILLWAY & POWER HOUSE

CONCRETE ARCH DAM

ROCKFILL DAMS

BARRAGE URI HE PROJECT

SHIMEN DOUBLE CURVATURE ARCH DAM CHINA

SHIZITAN ROCKFILL DAMCHINA

UNDERGROUND POWERHOUSETEHRI HEP

EARTHEN DAM WITH CONCRETE SPILLWAY & POWER HOUSE

CONCRETE ARCH DAM

IDUKKI ARCH DAM

CFRD UNDER CONSTRUCTIONDHAULIGANGA H.E. PROJECT

KENGKOU RCC DAM-CHINA

MOZITAN BUTRESS DAM CHINA

SANGTAO EARTH DAM CHINA

SPILLWAY RADIAL GATESTEHRI H.E PROJECT

PI-SHI_HANG AQUEDUCT

FISH LADDER-URI BARRAGE

POWER INTAKE SUBANSIRI LOWER H.E.PROJECT

INTAKE STRUCTURETEHRI HEP

DESILTING BASIN-URI HEP

SURPLUS SLUICES-METTUR DAM

HEAD RACE TUNNELNATHPA JHAKRI H.EPROJECT

TUNNEL INSIDE AT BIFURCATION

ROCK BOLTING

SHOTCRETING

SEEPAGE INSIDE TUNNEL

DRILLING JUMBO

TUNNEL BORING MACHINE

PENSTOCKS LOKTAK HEP-MANIPUR

POWERHOUSE L-SECTION

POWER HOUSE TURBO GENERATORS-METTUR DAM

POWERHOUSE MACHINE HALL-URI HE PROJECT

POWERHOUSE MACHINE HALL KENGKOU HEP

SPIRAL CASING UG POWERHOUSE TEHRI HEP

SPIRAL CASING

POWER HOUSE ROTOR INSTALLATIONBAISHAM HEP - CHINA

POWER HOUSE STATOR INSTALLATION BAISHAM HEP - CHINA

CANAL HEAD POWER HOUSE SARDAR SAROVAR HEP

TURBO GENERATORSINSTALLATION - UG POWERHOUSETEHRI HEP

TAILRACE OUTLET PORTALURI H.E.PROJECT

THANK YOU

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