Hydro power plants

Hydro power plantsTail waterDraft tube gateDraft tubeTurbineMain valvePenstockAir inletInlet gateSurge shaftTunnelSand trapTrash rackSelf closing valve

The principle the water conduits of a traditional high head power plant

Ulla- Frre Original figur ved Statkraft Vestlandsverkene

Arrangement of a small hydropower plant

H = 39 mQ = 513 m3/sP = 182 MWDrunner=7,5 mLigga Power Plant, Norrbotten, Sweden

Borcha Power Plant, TurkeyH = 87,5 mP = 150 MWDrunner=5,5 m

Water intakeDamCoarse trash rackIntake gate Sediment settling basement

DamsRockfill damsPilar og platedammerHvelvdammer

Rock-fill damsCoreMoraine, crushed soft rock, concrete, asphaltFilter zoneSandy gravelTransition zoneFine blasted rockSupporting shellBlasted rock

Slab concrete dam

Arc dam

Gates in Hydro Power Plants

Types of Gates

Radial GatesWheel GatesSlide GatesFlap GatesRubber Gates

Radial Gates at lvkarleby, Sweden

Radial Gate The forces acting on the arc will be transferred to the bearing

Slide GateJhimruk Power Plant, Nepal

Flap Gate

Rubber gateReinforced rubberOpen position Flow disturbanceReinforced rubberClosed position Bracket Air inlet

Circular gateManholeHinge Ladder RibsPipeEnd coverBolt Fastening element Frame Seal

Circular gateJhimruk Power Plant, Nepal

Trash RacksPanauti Power Plant, Nepal

Theun Hinboun Power PlantLaos

GravfossPower PlantNorway

Trash Rack size:Width: 12 meterHeight: 13 meter

Stainless Steel

CompRack Trash Rack delivered by VA-Tech

Cleaning the trash rack

PipesMaterialsCalculation of the change of length due to the change of the temperatureCalculation of the head lossCalculation of maximum pressure Static pressureWater hammerCalculation of the pipe thicknessCalculation of the economical correct diameterCalculation of the forces acting on the anchors

MaterialsSteelPolyethylene, PEGlass-fibre reinforced Unsaturated Polyesterplastic , GUPWoodConcrete

Materials

Steel pipes in penstockNore Power Plant, Norway

GUP-PipeRaubergfossen Power Plant, Norway

Wood PipesBreivikbotn Power Plant, Norwayvre Porsa Power Plant, Norway

Calculation of the change of length due to the change of the temperatureWhere:DL =Change of length[m]L =Length[m]a=Coefficient of thermal expansion [m/oC m]DT =Change of temperature[oC]

Calculation of the head lossWhere:hf=Head loss[m]f =Friction factor[ - ]L =Length of pipe[m]D =Diameter of the pipe[m]c =Water velocity[m/s]g=Gravity[m/s2]

ExampleCalculation of the head lossPower Plant data:H =100 m HeadQ=10 m3/sFlow RateL =1000 mLength of pipeD=2,0 mDiameter of the pipeThe pipe material is steelWhere:c=3,2 m/sWater velocityn=1,30810-6 m2/sKinetic viscosityRe=4,9 106Reynolds number

0,013Where:Re=4,9 106Reynolds numbere=0,045 mmRoughnessD=2,0 mDiameter of the pipee/D=2,25 10-5 Relative roughnessf =0,013Friction factorThe pipe material is steel

ExampleCalculation of the head lossPower Plant data:H =100 m HeadQ=10 m3/sFlow RateL =1000 mLength of pipeD=2,0 mDiameter of the pipeThe pipe material is steelWhere:f =0,013Friction factorc=3,2 m/sWater velocityg=9,82 m/s2Gravity

Calculation of maximum pressureStatic head, Hgr (Gross Head)Water hammer, DhwhDeflection between pipe supportsFriction in the axial directionHgr

Maximum pressure rise due to the Water HammercDhwh=Pressure rise due to water hammer[mWC]a = Speed of sound in the penstock[m/s]cmax=maximum velocity [m/s]g=gravity[m/s2]Jowkowsky

Example Jowkowskyc=10 m/sa = 1000[m/s]cmax=10 [m/s]g=9,81[m/s2]

Maximum pressure rise due to the Water HammerWhere:Dhwh=Pressure rise due to water hammer[mWC]a = Speed of sound in the penstock[m/s]cmax=maximum velocity [m/s]g=gravity[m/s2]L=Length[m]TC=Time to close the main valve or guide vanes [s]

Example

L = 300[m]TC=10 [s]cmax=10 [m/s]g=9,81[m/s2]LC=10 m/s

Calculation of the pipe thicknessBased on:Material properties Pressure from:Water hammerStatic headWhere:L=Length of the pipe[m]Di=Inner diameter of the pipe[m]p=Pressure inside the pipe[Pa]st=Stresses in the pipe material[Pa]t= Thickness of the pipe[m]Cs=Coefficient of safety[ - ]r = Density of the water[kg/m3]Hgr=Gross Head[m]Dhwh=Pressure rise due to water hammer[m]

ExampleCalculation of the pipe thicknessBased on:Material properties Pressure from:Water hammerStatic headWhere:L=0,001 mLength of the pipeDi=2,0 mInner diameter of the pipest=206 MPaStresses in the pipe materialr = 1000 kg/m3Density of the waterCs=1,2Coefficient of safetyHgr=100 m Gross HeadDhwh=61 mPressure rise due to water hammer

Calculation of the economical correct diameter of the pipeDiameter [m]Cost [$]Installation costs, KtCosts for hydraulic losses, KfTotal costs, Ktot

ExampleCalculation of the economical correct diameter of the pipeHydraulic LossesWhere:PLoss =Loss of power due to the head loss[W]r=Density of the water[kg/m3]g=gravity[m/s2]Q=Flow rate[m3/s]hf=Head loss[m]f=Friction factor[ - ]L =Length of pipe[m]r =Radius of the pipe[m]C2=Calculation coefficientPower Plant data:H =100 m HeadQ=10 m3/sFlow Ratehplant=85 %Plant efficiencyL =1000 mLength of pipe

ExampleCalculation of the economical correct diameter of the pipeCost of the Hydraulic Losses per yearWhere:Kf=Cost for the hydraulic losses[]PLoss =Loss of power due to the head loss[W]T=Energy production time [h/year]kWhprice=Energy price[/kWh]r =Radius of the pipe[m]C2=Calculation coefficient

ExampleCalculation of the economical correct diameter of the pipePresent value of the Hydraulic Losses per yearWhere:Kf=Cost for the hydraulic losses[]T=Energy production time [h/year]kWhprice=Energy price[/kWh]r =Radius of the pipe[m]C2=Calculation coefficientPresent value for 20 year of operation:Where:Kf pv=Present value of the hydraulic losses[]n=Lifetime, (Number of year )[-]I=Interest rate[-]

ExampleCalculation of the economical correct diameter of the pipeCost for the Pipe MaterialWhere:m=Mass of the pipe[kg]rm=Density of the material[kg/m3]V=Volume of material[m3]r=Radius of pipe[m]L =Length of pipe[m]p=Pressure in the pipe[MPa]s =Maximum stress[MPa]C1=Calculation coefficientKt=Installation costs[]M=Cost for the material[/kg]NB:This is a simplification because no other component then the pipe is calculated

ExampleCalculation of the economical correct diameter of the pipeInstallation Costs:PipesMaintenanceInterestsEtc.

ExampleCalculation of the economical correct diameter of the pipeWhere:Kf=Cost for the hydraulic losses[]Kt=Installation costs[]T=Energy production time [h/year]kWhprice=Energy price[/kWh]r =Radius of the pipe[m]C1=Calculation coefficientC2=Calculation coefficientM=Cost for the material[/kg]n=Lifetime, (Number of year )[-]I=Interest rate[-]

ExampleCalculation of the economical correct diameter of the pipe

Calculation of the forces acting on the anchors

Calculation of the forces acting on the anchorsF5F4F3F1F2FF1 =Force due to the water pressure[N]F2 =Force due to the water pressure[N]F3 = Friction force due to the pillars upstream the anchor[N]F4 = Friction force due to the expansion joint upstream the anchor [N]F5 = Friction force due to the expansion joint downstream the anchor [N]

Calculation of the forces acting on the anchorsGFR

Valves

Principle drawings of valvesOpen positionClosed positionSpherical valveGate valveHollow-jet valveButterfly valve

Spherical valve

Bypass system

Butterfly valve

Butterfly valve

Butterfly valvedisk types

Hollow-jet Valve

Pelton turbinesLarge heads (from 100 meter to 1800 meter)Relatively small flow rate Maximum of 6 nozzlesGood efficiency over a vide range

KvrnerJostedal, Norway*Q = 28,5 m3/s*H = 1130 m*P = 288 MW

Francis turbinesHeads between 15 and 700 meter Medium Flow RatesGood efficiency =0.96 for modern machines

SVARTISENP = 350 MWH = 543 mQ* = 71,5 m3/SD0 = 4,86 mD1 = 4,31mD2 = 2,35 mB0 = 0,28 mn = 333 rpm

Kaplan turbinesLow head (from 70 meter and down to 5 meter)Large flow rates The runner vanes can be governed Good efficiency over a vide range