Hydropower engineering -Hydraulics

Dams and Reservoirs -Hydraulics engineering

1. Hydraulics Engineering
Introduction to
Hydropower Engineering
Dr. M. MubashirQureshi

2. Introduction
Poweristhebasicnecessityforthedevelopmentofa
country
Per-capitaconsumptionofelectricenergyisdeemedas
anindexofthestandardoflivinginanationinthe
present-day-world.
Developmentoflarge,mediumandsmallscale
industriesdependuponelectricpowergeneration.
Thisnecessitatestoutilizethepresentresourceof
energywithutmostcareandwithmaximumefficiency.

3. Introduction
HYDROPOWER INSTALLED CAPACITY BY REGION
Source:-https://www.worldenergy.org/data/resources/resource/hydropower/

4. Introduction
TOP HYDROPOWER PRODUCING COUNTRIES
Source:-https://www.worldenergy.org/data/resources/resource/hydropower/
MTOEis an acronym that may refer to: Million Tonnesof Oil Equivalent
1Mtoe = 11630 kwh

5. Introduction
HYDROPOWER INSTALLED CAPACITY BY REGION
Source:-https://www.worldenergy.org/data/resources/resource/hydropower/

6. Introduction
Energy Resources:
Fossil Fuel (oil, gas, and coal etc)
Wind
Water in Rivers
Waves and Tides in Ocean
Solar Energy
Atomic/Nuclear Energy
Withgoodplanningandmanagement,hydropowerisacatalystforthe
sustainableimprovementofpeople’slives.

7. Introduction
Power Generation Pattern of the world

8. Power Sector Installed Capacity of
Pakistan
As of (2004)
Hydropower Potential in Pakistan = 41,000 MW (approx.)

9. Power Sector Installed Capacity of
Pakistan
Power Generation Pattern of the Pakistan (2004)
Access of population to electricity in Pakistan = 62%

10. Classification of Energy Resources
Renewable Energy:These are sources of energy produced
continuously in nature and will not get exhausted eventually in
future. e.g., Hydel Energy, Solar Energy, Tidal Energy, Geo-thermal
Energy and Biomass.
Non-Renewable Energy:These are sources will get exhausted
eventually in future. e.g., Energy from Fossil Fuel.
Conventional Energy:Fossil Fuels, Hydel Power, Nuclear Energy
Non-Conventional Energy:Solar Energy, Wind Energy, Tidal
Energy, Ocean Thermal Energy, Geothermal Energy and Biomass.
Commercial Energy:Coal, oil, gas, Hydel Energy, Nuclear
Non-Commercial Energy:Wood, wastes etc

11. Classification of Energy Resources
Based on net yield of energy:
Primary Energy Source:The energy source which provides a net
source of energy.
E.g. coal, natural gas, uranium, oil.
Secondary Energy Source:From this source, the yield of energy is
less than input.
E.g. Solar, Wind, Tidal, Water Energy.
Supplementary Energy Source:If the net energy yield provided by
the energy source is zero, it is called supplementary energy
source.
E.g. thermal insulation.

12. Hydropower (Hydel Power)
Time
Q
✓Hydropoweris extracted from the natural potential of usable water
resources.
✓If the water is available in the river as above, then for the production
of energy reservoirs are made so as to make availability of water
throughout the year
About one quarter of the world’s power requirement is at present derived in this
way.
P=γQH
Where
P= Hydropower
Q = River discharge
H= Available head

13. How the Hydropower Works
Hydropower plants
capturetheenergyof
fallingwater to
generateelectricity.A
turbineconvertsthe
kineticenergyof
fallingwaterinto
mechanical energy.
Thenagenerator
converts the
mechanical energy
fromtheturbineinto
electricalenergy
With good planning and management, hydropower is a catalyst for the
sustainable improvement of people’s lives.

14. Essential Elements of Hydropower
Station
➢Interceptionofwater
➢Conveyanceofwater
➢PowerStation
➢SafeDisposalofusedwater
➢Transmissionofelectricity

16. Components of hydelscheme
The principal componentsare:
1.Forebay
2.Intakestructure
3.Penstocks
4.Surgetank
5.Turbines
6.Powerhouse
7.Drafttube
8.Tailrace

18. Forebay
•Enlarged body of water provided in frontof
penstock.
•Provided in case of run off river plantsand
storageplants.
•Main function to store water whichis
rejected byplant.
•Power house located closed todam
penstock directly take water from
reservoir, reservoir act asforebay.

20. Intakestructure
•Water conveyed from forebay to
penstocks through intakestructures.
•Main components are trash rack andgate.
•Trash rack prevent entry ofdebris.

21. Penstocks
•open or closed conduits which carrywater
to theturbines.
•made of reinforced concrete or steel.
Concrete penstocks are suitable forlow
heads less then30mtrs.
•steel penstocks are designed forany
head.
•thickness of penstocks increaseswith
head or waterpressure

22. •penstocks gates are fixed to initial of
penstocks, and flow of water iscontrolled
by operating penstockgates.
•Either buried in ground or keptexposed.

23. Surgetank
•additional storage for nearto
turbine, usually provided in highhead
plants.
•located near the beginning ofthe
penstock.
•As the load on the turbine decreasesor
during load rejection by the turbine the
surge tank provides space for holding
water.

24. •surge tank over comesthe
abnormalpressure
in the conduit when load on the turbinefalls
and acts as a reservoir during increase of
load
ontheturbine.

25. Turbines
•turbines are used to convert theenergy
water of falling water into mechanical
energy.
•water turbine is a rotary engine thattakes
energy from movingwater.
•flowing water is directed on to the blades
of a turbine runner, creating a force onthe

26. •Since the runner is spinning, the forceacts
through a distance n this way, energy is
transferred from the water flow to the
turbine.
•The principal types of turbinesare:
1)Impulseturbine
2)ReactionTurbine

27. Impulseturbines:mainly used in highhead
plants.
•theentirepressureofwaterisconvertedinto
kineticenergyinanozzleandthevelocityof
thejetdrivesthebladesofturbine.
•Thenozzleconsistofaneedle,andquantity
ofwaterjetfallingontheturbineiscontrolled
thisneedleplacedinthetipofthenozzle.
•Iftheloadontheturbinedecreases,the
governorpushestheneedleintothe
nozzle,therebyreducingthequantityofwater
strikingtheturbine.

28. •Examples of Impulse turbinesare:
•PeltonWheel.
•Turgo
•Michell-Banki (also known as theCross
flow or Ossbergerturbine.

30. Reaction turbines :are mainly for
lowand medium headplants.
•In reaction turbine the water enters the runner
partly with pressure energy and partly with
velocityhead.
•Most water turbines in use are reaction turbines
and are used in low (<30m/98 ft) and medium
(30-300m/98–984 ft)headapplications.
•In reaction turbine pressure drop occurs in both
fixed and movingblades.

31. •Inthisturbinetherunnerbladeschanged
withrespecttoguidevaneopening.
•Asthesuddendecreaseofloadtakes
place,theguidevanelimitdecreases
accordingtothatrunnerbladecloses.
•Examples of reaction turbinesare:
➢Francisturbine
➢Kaplanturbine

32. Kaplan
Francis

33. Drafttube
•is a pipe or passage of gradually
increasing cross sectional area,which
connect to the exit to tailrace.
•it reduces high velocity ofwater
discharged by theturbine.
•draft tube permits turbines to be installed
at a higher level than the tailrace
level, which help the maintaince andrepair
ofturbines.

35. Powerhouse
•Power house contains the electro
mechanical equipment i.e. hydropower
turbine, Generator,excitation
system, maininlet
valves, transformers, Switchyard,DC
systems, governor, bus duct, step up
transformers, step down
transformers, high voltagesswitch
gears, control metering for protectionof
systems.

36. Tailrace
•tail race tunnel or channel are providedto
direct the used water coming out of draft
tube back to theriver.
•important criteria of designing the tailrace
is kind of draft tube, the gross head and
geographical situation of thearea.
•Tailraceisdesignedinsuchawaythat
waterhammerisminimizeswhenwater
leavesthedrafttube.

38. The amount of electricity that can be generated by a
hydropower plant depends on twofactors:
•flow rate -the quantity of water flowing in a given
time;and
•head -the height from which the waterfalls.
The greater the flow and head, the more electricity
produced.
Flow Rate = the quantity of waterflowing
Head = the height from which waterfalls
Powergeneration

39. HydropowerOffersaHighLevelofService
supportingbetterperformanceofother
technologies
◼EFFICIENCY Hydropower shows the:
❑Best conversion rate (~90%) due to the direct transformation of hydraulic
forces to electricity
❑Most favorable energy payback ratio considering the amount of energy
required to build, maintain and fuel a power plant compared with the
energy it produces during its normal life span
◼FLEXIBILITY: Thanks to the storage of potential electricity in
reservoirs, hydropower:
❑Has the capacity to provide base and peak-load
❑Is the ideal back-up source for intermittent electricity sources such as
wind and solar
❑Optimizes efficiency of less flexible fossil or nuclear generating options
has the capacity to follow demand fluctuations almost instantly
❑Offers a quick response to failings in power grids

40. Hydropower Offers a High Level of Service
supporting better performance of other
technologies
◼RELIABILITY: Hydropower is:
❑A proven and well-advanced technology based on more than a century
of experience the backbone of an integrated renewable grid
❑A clean source of renewable energy with the capacity to make a
significant contribution to the world’s ever-growing need for electricity

41. Types of Hydropower Development
➢Run-of-RiverPlant(LocalDevelopment)
➢Aweirorbarrageisbuiltacrosstheriverandthelowheadisused
togeneratepower.
➢Ithasverylimitedstoragecapacityandcanonlyusewaterwhen
available
➢Itsfirmcapacityislow,becausewatersupplyisnotuniform
throughouttheyear,butitcanserveasabaseloadplant

42. Types of Hydropower Development
➢DiversionCanalPlant
➢Theflowfromimpoundingwaterintheriverupstreamofthebarrage
isdivertedintoapowercanalwhichrejoinstheriverfurther
downstreamwithpowerstationlocatedeithernexttotheintakeor
withthecanalorattheoutlet.

43. Types of Hydropower Development
➢StoragePlant
➢Thedamstructureisseparatedfromthepowerstationbya
considerabledistanceoverwhichthewaterisconveyed,
generallybyatunnelandpipeline,soastoachievemediumor
highheads.
➢Thereservoirstorageupstreamofthedamincreasesthefirm
capacityoftheplantsubstantially,dependingupontherun-off
andpowerrequirements.
➢Theplantmaybeusedasabase-loadand/orpeak-load
installation.

44. Types of Hydropower Development

45. Types of Hydropower Development

46. Types of Hydropower Development
➢PumpStoragePlant
➢Wherethenaturalannualrun-offisinsufficienttojustifya
conventionalhydroelectricinstallation,andwhereitispossible
tohavereservoirsatthehead-andtailwaterlocations,the
waterispumpedbackedfromlowertotheheadwater
reservoir.
➢Thiskindofplantgeneratesenergyforpeakload,andatoff-
peakperiodswaterispumpedbackforfutureuse.
➢Apumpedstorageplantisaneconomicaladditiontoasystem
whichincreasetheloadfactorofothersystemsandalso
providesadditionalcapacitytomeetthepeakloads.

47. Head Classification of Hydropower
Plants
➢LowHeadScheme
➢<50m
➢MediumHeadScheme
➢50to300m
➢HighHeadScheme
➢>300m

48. Stream Flow Data Essential for the Assessment of
Water Power Potential
➢TheFollowinghydrologicaldataarenecessary;
➢Thedaily,weeklyormonthlyflowoveraperiodof
severalyears,todeterminetheplantcapacityand
estimatedoutputwhicharedependentonthe
averageflowofthestreamanditsdistribution
duringtheyear
➢Lowflows,toassesstheprimary,firmor
dependablepower.

49. Stream Flow Data Essential for the Assessment of
Water Power Potential
➢StreamDataAnalysis:
➢Atypicalstreamflowhydrograph,includingadryperiodfromwhich
thefrequencyofoccurrenceofacertainflowduringtheperiodcan
becalculated.

50. Stream Flow Data Essential for the Assessment of
Water Power Potential
➢FlowDurationCurve:
➢Itisaplotofthestreamflowinascendingordescending
orderanditsfrequencyofoccurrenceasapercentageof
timecoveredbytherecord.

51. Stream Flow Data Essential for the Assessment of
Water Power Potential
➢PowerDurationCurve:
➢Iftheavailableheadandefficiencyofthepowerplant
areknown,theflowdurationcurvemaybeconverted
intopowerdurationcurve.
➢Thepowerwhichisavailablefor95%to97%ofthetime
onthereservoirregulatedschemeisusuallyconsidered
PrimaryofFirmpower.
➢Allthepowerinexcessofprimarypoweriscalled
SecondaryorSurplusPower.

52. Stream Flow Data Essential for the Assessment of
Water Power Potential

53. Stream Flow Data Essential for the Assessment of
Water Power Potential
➢MassCurve:isthecurveofaccumulatedtotalinflowagainst
time.
◼DemandCurve:isthecurveofaccumulatedtotaldemand
againsttime.
Inflow &
Demand
Time
Inflow &
Demand
Time
Masscurveisusedtoestimatestoragerequirementsanduseableflowforpower
production.

54. Numerical Problems:
Problem#1:
Theavg.monthlyflowsofastreaminadryyearareasfollows:
Month Discharge (m
3
/sec)
January 117
February 150
March 203
April 117
May 80
June 118
July 82
August 79
September 58
October 45
November 57
December 152

55. Numerical Problems:
Problem#1:
Itisintendedtodesignahydroelectricpowerplantusingthe
followingdata:
Netheadatplantsite=20m
overallefficiencyofturbine=90%
Plotflowandpowerdurationcurvesandcalculatethefirmand
secondarypoweravailablefromthissource.
itisintendedtodevelopatafirmrateof15Mwatteitherby
providingastorageorbyprovidingastandbydieselwithnostorage.
Determineminimumcapacityofreservoirandofthedieselunit.
Howmuchflowisavailableforaparticular%ageoftime.

57. Numerical Problems:
Problem#2:
Averageannualflowsinriverindusataproposeddamsiteis120BCM.
Thedamistobebuiltonavaryingheadfrom50mto100monthe
turbines,estimate:
Waterpowerpotentialfromthisproposedhydalpowerstationif
overallefficiencyofturbinesis88%andthatofgeneratoris92%.Find
theelectricalenergyavailableontheschemeinkWHperyearinone
year.Thehydrologicaldatasuggeststhatavg.headavailableforsix
monthsis50m,fornextthreemonths,80mandforrestofthe
monthsis100m.

59. SITESELECTION

60. SITESELECTION
1.Availability ofwater
–All other designs are based onit.
–Estimate should be made about the averagequantity
ofwateravailablethroughouttheyear
aboutmaximumandminimumquantity
andalso
ofwater
available during theyear.
–These details are necessary to decide the capacity of
the hydropower plant,and
–Italsoprovideadequatespillwaysorgaterelief
during floodperiod.

61. SITESELECTION
2.Waterstorage
–Sincethereaiswidevariationinrainfallduringthe
year,thereforeitisnecessarytostorethewaterfor
continuousgenerationofpower.Thestorage
capacitycanbecalculatedwiththehelpofmass
curve.
–Thetwotypesofstoragesinuseare
1.Thestorageissoconstructedthatitcanmakewater
availableforpowergenerationforoneyearonly.
2.Waterisavailableinsufficientquantityevenduringthe
worstdryperiods.

62. SITESELECTION
3.Waterhead
–Inordertogeneratearequisitequantityofpoweritis
necessarythatalargequantityofwateratsufficient
headshouldbeavailable.
–Anincreaseineffectiveheadforagivenoutput,
reducesthequantityofwaterrequiredtobesupplied
totheturbines.

63. SITESELECTION
4.Accessibility ofsite
–Thesitewherehydro-electricplantistobe
constructedshouldbeeasyaccessible.Thisis
importantiftheelectricpowergeneratedistobe
utilisedatorneartheplantsite.
–Thesiteselectedshouldhavetransportationfacilities
ofrailandroad.

64. SITESELECTION
5.Distancefromtheloadcentre
–Powerplantshouldbesetupneartheloadcentre,
thiswillreducethecostofmaintenanceof
transmissionline.

65. SITESELECTION
6.Typeofthelandofthesite
–Thelandtobeselectedforthesiteshouldbecheapand
rocky.
–Theidealsitewillbeonewherethedamwillhavelargest
catchmentareatostorewaterathighheadandwillbe
economicalinconstruction.
–Necessaryrequirementofthefoundationrocksfor
masonrydamare-
•Therockshouldbestrongenoughtowithstandthestresses
transmittedfromthedamstructureaswellasthethrustofthe
waterwhenthereservoirisfull.
•Therockinthefoundationofthedamshouldbereasonably
impervious.
•Therockshouldremainstableunderallcondtitions.

66. SITESELECTION