Hydrology for HYDROPOWER PLANTS MODULE - ing.unitn.itrighetti/lezioni...
Transcript of Hydrology for HYDROPOWER PLANTS MODULE - ing.unitn.itrighetti/lezioni...
Hydrology for
HYDROPOWER PLANTS
MODULE
Bruno Majone
(a.a. 2014/15, 40 hours)
Bruno MajoneDepartment of Civil, Environmental and Mechanical
Engineering
University of Trento
e-mail: [email protected]
(room 401, DICAM)
tel.: 0461 28 2637
Objectives: from the syllabus“By the end of the course, students should be able to: perform the main
hydrological analyses needed for the design of hydropower systems and the
simulation of its productivity…...........”
Contents: from the syllabus
Introduction: Functioning of a hydropower system; classification and main components
Reservoir hydrological design: hydrodinamic curves; flow duration curves volume design. OperationReservoir hydrological design: hydrodinamic curves; flow duration curves volume design. Operation
simulation in hydropower planning.
Streamflow measurements: weirs, velocity-area method, dilution gauging, rating curves,
measurement errors and their influence on rating curves.
Catchment-scale hydrological models: modules composing a hydrological model; snow
accumulation and melting; models of evapotranspiration, interception by vegetation and water
infiltration; continuous hydrological models; construction of a catchment-scale hydrological model;
model calibration and validation; flood models: Instantaneous Unit Hydrograph.
Lectures Slides (part of them with courtesy of Alberto
Bellin, University of Trento, and Gianluca Botter,
University of Padova).
Book:
S. L. Dingman, Physical Hydrology, Prentice Hall, New
Jersey, 1994.
Bibliography
Jersey, 1994.
The examination consists of two elements: final oral
discussion, presentation of the homework.
Exam
Hydro-Electric Power Plant
Hydropower energy is ultimately derived from the sun, which
drives the water cycle. In the water cycle, rivers are recharged
in a continuous cycle. Because of the force of gravity, water
flows from high points to low points. There is kinetic energy embodied in the flow of water.
How a Hydroelectric Power System Works - Part 1
Flowing water is directed at
a turbine (remember
turbines are just advanced
waterwheels). The flowing
water causes the turbine towater causes the turbine to
rotate, converting the water’s
kinetic energy into
mechanical energy.
How a Hydroelectric Power System Works – Part 2
The mechanical energy produced by the turbine is converted into
electric energy using a turbine generator. Inside the generator,
the shaft of the turbine spins a magnet inside coils of copper wire.
It is a fact of nature that moving a magnet near a conductor
causes an electric current.
How much electricity can be generated by a hydroelectric power plant?
The amount of electricity that can be generated by a
hydropower plant depends on two factors:
• flow rate - the quantity of water flowing in a given time; and
• head - the height from which the water falls.
The greater the flow and head, the more electricity produced.
When more water flows through a turbine, more electricity
can be produced. The flow rate depends on the size of the
river and the amount of water flowing in it. Power production
is considered to be directly proportional to river flow. That
is, twice as much water flowing will produce twice as much
electricity.
Flow Rate = the quantity of water flowing
The farther the water falls, the more power it has. Thus Power
production is directly proportional to head. That is, water
falling twice as far will produce twice as much electricity.
Head = the height from which water falls
Principles of a hydropower system
[m3/s]
Line of the gross head Hydraulic losses
Total head Piezometric line
ηρ HQP 81.9=
[m3/s][m]
P =QH
102η
[l/s] [m]
penstock
Example of a complex hydropower system
Hydropower plants
Hydropower plant layout
Essential features of Hydro-Electric Power Plant
The essential features of a water power plant are:
1. Catchment area.
2. Reservoir.
3. Dam and intake house.
4. Water way.4. Water way.
5. Power house.
6. Tail race or outlet water way.
1. Catchment Area.
The catchment area of a hydro plant is the whole area
behind the dam, draining into a stream or river across which
the dam has been built at a suitable place.
2- Water reservoir:� In a reservoir the water collected
from the catchment area is stored
behind a dam.
� Catchment area gets its water from
rain and streams.
� The level of water surface in the
reservoir is called Head water level.
Note: Continuous availability of water
is a basic necessity for a hydro-
electric power plant.
3- Dam :� The purpose of the dam is to store
the water and to regulate the out
going flow of water.
� The dam helps to store all the
incoming water. It also helps to
increase the head of the water. In
order to generate a required quantity
of power it is necessary that a
sufficient head is available.16
• Dam are classified based on following factors:
a) Function
b) Shape
c) Construction material
d) Design
a) Based on function the dam may be called as storage dam, diversion dam or detention dam.
b) Based on the shape the dam may of trapezoidal section & b) Based on the shape the dam may of trapezoidal section & arch type.
c) The materials used for constructing dams are earth, rock pieces, stone masonry, reinforced concrete.
d) According to structural design the dam maybe classified as:
i. Gravity dam
ii. Arch dam
iii. Buttress dam
Gravity dam:
Resist the pressure of water by its
weight.
Construction of material used for his
dam, is solid masonry or concrete.
Arch dam: Hoover
Types of Dam
Arch dam:
It resist the pressure of water partly due
to its weight and partly due to arch
action.
Buttress dam:
Buttress supporting a flat slab.
When cost of reinforced concrete is high
such type of dam is selected.
Hoover
Dam
Spillway:
• Excess accumulation of water endangers the
stability of dam construction. Also in order to
avoid the over flow of water out of the dam
especially during rainy seasons spillways are
provided. This prevents the rise of water level
4. Water ways. Water ways are the passages, through which the water is conveyed to the
turbines from the dam. These may include tunnels, canals, flumes, forebays and
penstocks and also surge tanks.
A forebay is an enlarged passage for drawing the water from the reservoir or the
river and giving it to the pipe lines or canals.
provided. This prevents the rise of water level
in the dam.
• Spillways are passages which allows the
excess water to flow to a storage area away
from the dam.
Gate:
• A gate is used to regulate or control the flow
of water from the dam.
Penstock:
• It is a passage that carries water from the
reservoir to the surge tank. 19
The gate controlling the water
flowing into the channel.
The penstock conveying water
from the intake to the power
house. Concrete (low heads) or
steel (all heads) material.
Surge tank:
• A Surge tank is a small reservoir or tank in which the water levelrises or falls due to sudden changes in pressure.
Purpose of surge tank:
• To serve as a supply tank to the turbine when the water in the pipeis accelerated during increased load conditions and as a storagetank when the water is decelerating during reduced load conditions.
• To reduce the distance between the free water surface in the dam
4. Water ways (continues…)
• To reduce the distance between the free water surface in the damand the turbine, thereby reducing the water-hammer effect onpenstock and also protect the upstream tunnel from high pressurerise.
Water-hammer effect :
• The water hammer is defined as the change in pressure rapidlyabove or below normal pressure caused by sudden change in therate of water flow through the pipe, according to the demand ofprime mover i.e. turbine.
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Number of penstock
A hydro Power Plant uses a number of turbine which are to
be supplied water through penstock.
• To use a single penstock for the whole a plant.
• To use on penstock for each turbine separately.
• To provide multiple penstock but each penstock supplying
water to at least two turbine.water to at least two turbine.
Factors for Selecting number of penstocks:
• Economy.
• Operational safety.
• Transportation facilities.
5. Power House.The power house is a building in which the turbines, alternators and theauxiliary plant are housed. Some important items of equipmentprovided in the power house are as follows:
i.Turbines
ii.Generators
iii.Governors
iv.Relief valve for penstock setting
v.Gate valve
vi.Transformervi.Transformer
vii.Switch board equipment and instruments
viii.Oil circuit breaker
ix.Storage batteries
x.Outgoing connections
xi.Cranes
xii.Shops & offices
� Turbine’s function is to convert the K.E of moving water into
mechanical energy.
� The water strikes and turns the large blades of a turbine,
which is attached to a generator above it by way of a shaft.
24The runner of the small water turbine
A hydroelectric generator converts
this mechanical energy into
electricity.
The operation of a generator is
based on the principles discovered
by Faraday. He found that when a
magnet is moved past a conductor
(in this case, coils of copper wire),(in this case, coils of copper wire),
it causes electricity to flow through
the wire.
6. Draft tube, Tail water level and Tail race:
• Draft tube is connected to the outlet of the turbine and itallows the turbine to be placed above the tail water level.
• Tail water level is the water level after the discharge fromthe turbine. The discharged water is sent to the river, thusthe level of the river is the tail water level.
•After passing through the
turbine the water returns
to the river trough a short
canal called a tailrace.
Classification of hydro-Electric power plant
The classification of hydro electric power plant depend on the
following factors:
1)Classification based on the hydraulic features
a)Storage plant.
b)Pumped storage.
c)Run-of-the-river plant.c)Run-of-the-river plant.
d)Marine.
e)Underground.
2)Availability of Head of Water:
a)Low head plant. Operating head < 15m.
b)Medium head plant. Operating head 15 to 50m.
c)High head plants Operating head > 50m.
Storage plant (already seen)
• Most hydroelectric power comes from the potential energy
of dammed water driving a water turbine and generator
• The power extracted from the water depends on the
volume and on the difference in height between the source
and the water's outflow
• This height difference is called the head
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• This height difference is called the head
• The amount of potential energy in water is proportional to
the head
• A large pipe (the "penstock") delivers water to the turbine
Pumped-storage
• This method produces electricity to supply high peak
demands by moving water between reservoirs at different
elevations
• At times of low electrical demand, excess generation
capacity is used to pump water into the higher reservoir
• When there is higher demand, water is released back into
the lower reservoir through a turbine
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the lower reservoir through a turbine
• Pumped-storage schemes currently provide the most
commercially important means of large-scale grid energy
storage and improve the daily capacity factor of the
generation system
Run-of-the-river• Run-of-the-river hydroelectric stations are those with small
or no reservoir capacity, so that the water coming from
upstream must be used for generation at that moment, or
must be allowed to bypass the dam.
• It may involve a diversion of a portion of the stream
through a canal or penstock, or it may involve placement
of a turbine right in the stream channel. Run-of-the-river
systems are often low-head.
30
systems are often low-head.
Marine Power
�Marine current power, which captures the kinetic energy from
marine currents
�Tidal power, which captures energy from the tides in horizontal
direction:
� Tidal stream power, usage of stream generators, somewhat
similar to that of a wind turbine
� Tidal barrage power, usage of a tidal dam
� Dynamic tidal power, utilizing large areas to generate head.
31
� Dynamic tidal power, utilizing large areas to generate head.
�Wave power, the use ocean surface waves to generate power.
Wave device
Underground
An underground power station makes use of a large
natural height difference between two waterways, such as a
waterfall or mountain lake
• An underground tunnel is constructed to take water from
the high reservoir to the generating hall built in an
underground cavern near the lowest point of the water
tunnel and a horizontal tailrace taking water away to the
lower outlet waterway
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lower outlet waterway
Low head plant
• Operating head is less than 15m.
• Small dam is required.
Medium head plant
• Operating head is less than 15 to 50m.
• Forebay is provided at the beginning of the penstock.
High head plant
• Operating head exceed 50m.
• Surge tank is attached to the penstock to reduce water
hammer effect on the penstock.
Advantages of hydro power production
• Water is a renewable energy source. Hydropower storage
systems complement other sources of renewable energy (i.e,
wind, solar, etc.).
• Maintenance and operation charges are very low. No costs for
fuel.
• The efficiency of the plant almost does not change with age.
• In addition to power generation, hydro-electric power plants are
also useful for flood control, irrigation purposes, fishery and
recreation.
• Long life time (100 to 125 years). Limited labor costs, easy
automatization.
Comparison with other methods of power generation
• Hydroelectricity eliminates the flue gas emissions from fossil fuelcombustion, including pollutants such as sulfur dioxide, nitric oxide,carbon monoxide, dust, and mercury in the coal
• Hydroelectricity also avoids the hazards of coal mining and theindirect health effects of coal emissions
• Compared to nuclear power, hydroelectricity generates no nuclear
37
• Compared to nuclear power, hydroelectricity generates no nuclearwaste, has none of the dangers associated with uranium mining, nornuclear leaks
• Compared to wind farms, hydroelectricity power plants have a morepredictable load factor
• If the project has a storage reservoir, it can generate power whenneeded. Hydroelectric plants can be easily regulated to followvariations in power demand
World hydroelectric capacity
39
World renewable energy share (2008), with hydroelectricitymore than 50% of all renewable energy sources
Disadvantages of hydro power production
• The initial cost of the plant is very high.
• Since they are located far away from the load center,
costs of transmission lines and transmission losses are
relevant.
• During drought season the power production may be
reduced or even stopped due to insufficient water in thereduced or even stopped due to insufficient water in the
reservoir.
• The risk of flow shortage may increase as a result of
climate change.
• Part of the water in the reservoir is lost by evaporation.
But these are only the economical disadvantages…..
Installation of new large hydropower projects today is very
controversial because of their negative environmental
impacts. These include:
�upstream flooding
�declining fish populations
�decreased water quality and flow
�reduced quality of upstream and downstream
environmentsenvironments
Glen Canyon June 1962 Glen Canyon June 1964
Ecosystem damage and loss of land
43
• Large reservoirs required for the operation of hydroelectric powerstations result in submersion of extensive areas upstream of thedams, destroying biologically rich and productive lowland andriverine valley forests, marshland and grasslands
• The loss of land is often exacerbated by the fact that reservoirscause habitat fragmentation of surrounding areas
• Hydroelectric projects can be disruptive to surrounding aquaticecosystems both upstream and downstream of the plant site
• Generation of hydroelectric power changes the downstream riverenvironment
• Water exiting a turbine usually contains very little suspended
44
• Water exiting a turbine usually contains very little suspendedsediment, which can lead to scouring of river beds and loss ofriverbanks
• Since turbine gates are often opened intermittently, rapid or evendaily fluctuations in river flow are observed (hydropeaking)
• Dissolved oxygen content of the water may change from pre-construction conditions.
• Depending on the location, water exiting from turbines is typicallymuch warmer than the pre-dam water, which can change aquaticfaunal populations, including endangered species, and preventnatural freezing processes from occurring.
Failure hazard
• Because large conventional dammed-hydro facilities
hold back large volumes of water, a failure due to poor
construction, terrorism, or other cause can be
catastrophic to downriver settlements and infrastructure
• Dam failures have been some of the largest man-made
disasters in history
• Also, good design and construction are not an adequate
45
• Also, good design and construction are not an adequate
guarantee of safety
Power production depends on:
- Head: difference between upstream and downstream
specific energy [m]
- Flow rate processed by the plant Q [m3/s]
- Hydropower plant efficiency η (0.70 - 0.85): a coefficient which
measures the fraction of hydraulic power actually converted into
electrical power (η <1).
- High efficiency (es. Thermal power plant efficiency = 0.42)
• Pipe efficiency ηP (0.90 – 0.95): it takes into account distributed
and local energy losses along the pipes
• Turbine efficiency ηT (0.80 -0.90): internal efficiency of the
turbine in turning hydraulic energy into mechanical energy
• Intrinsic efficiency ηO (~ 1): it takes into account losses due to • Intrinsic efficiency ηO (~ 1): it takes into account losses due to
power unit, auxiliary plants maintainance,
The values of efficiency reported here are indicative (actual values
depend on the type of hydropower plants).
- Hydropower plant efficiency η depends on the speed of the
turbine, on the head, on the flow processed......
Hydraulic Turbines
Advantages:
Simple in construction.
Easily controllable.
Efficient.
Ability to work at peak load.Ability to work at peak load.
Work on load variation.
Types of turbines:
a)Impulse
b)Reaction
IMPULSE TURBINES (Pelton):
- the potential energy is first completely turned into kinetic
energy in the distributor and then transformed into
mechanical energy (free surface water moves a suitable
runner)
- operate at normal (atmospheric) pressure
2. REACTION TURBINES (Francis,
Kaplan):
- the energy of water is not
completely turned into kinetics
energy before the entrance into the
turbine; the mechanical energy is
derived exploiting the combined
action of pressure and kineticsaction of pressure and kinetics
energy)
- water flows through the blades
exerting a force related to changes
in magnitude and direction of the
velocity during the flow path
- operate fully submerged (pressure
gradient across the runner)
Other Classifications(Streamflow and power)
Animations
Pelton turbine
http://www.youtube.com/watch?v=Jd5BN7SPkqI
Francis Turbine
http://www.youtube.com/watch?v=3BCiFeykRzo
Kaplan Turbine
http://www.youtube.com/watch?v=0p03UTgpnDU
Virtual turbineshttp://www.youtube.com/watchv=IZdiWBEzISM&list=PLD016622FEE1DF943
Useful links
General information on some dams and associated plants.
http://www.progettodighe.it/main/le-centrali/article/isola-
serafini-monticelli-d-ongina
Turbines:
http://www.arditosrl.eu/turbine.html
Reservoir Dimensioning
part of the slides courtesy of Gianluca Botter, part of the slides courtesy of Gianluca Botter,
UNIPD
The ability of humans to exploit natural streamflows as
water resources is by far improved by RESERVOIRS able
to STORE WATER and MODIFY the SEQUENCE of
NATURAL STREAMFLOWS.
Reservoir uses:
a. hydropower (transfer of water in space/time)
RESERVOIRS and WATER RESOURCES
a. hydropower (transfer of water in space/time)
b. irrigation (sink)
c. municipal (sink)
d. industrial (usually a sink)
Need for REGULATION: ensamble of operations to store
and release water volumes during time, in relation to the
storage potential of the reservoir and the request for
civil/industrial uses
LONG TERM REGULATION: inter-annual regulation,
chiefly corresponds to water savings during years with
larger water availability to satisfy the request on years
with lower water availability.
MID-TERM REGULATION: intra-annual regulation,
corresponds to water savings during months/season with
REGULATION and TIME HORIZONS
corresponds to water savings during months/season with
low request (low economical benefit from water use),
allowing for a more intensive usage during periods with
higher request (& economical rewards).
SHORT-TERM REGULATION: regulations carried out at
the daily level within a given season/month; same as mid-
term regulation but within shorter time horizons.
LONG TERM REGULATION: require the implementation
of climate change impact studies and associated analysis
of possible evolution of electricity market.
MID-TERM REGULATION: using deterministic inflows
and simplified/idealized schemes for utilizations
(traditional approach). We will concentrate on this.
REGULATION and TIME HORIZONS
(traditional approach). We will concentrate on this.
SHORT-TERM REGULATION: require the adoption of
sophisticated numerical tools, including the intra-seasonal
stochasticity of rainfall and streamflows, and focussing on
the weekly cycles of the water uses.
PLANT CAPACITY (DESIGN FLOW)
•Plant capacity chosen according to a fixed value of the
duration
•The Net Positive Value (revenues) of the project is
checked a posteriori
•Relies mostly on the designer experience
What is the definition of duration?
Water discharge curves
Duration curve (a real one)
FDC adimensionalizzata con la portata media per il bacino del fiume Noce. Per confronto si riporta anche la curva relativa all’Adige a
Trento.
Power available
�To design an hydroelectric
plant is fundamental the
knowledge of the duration
curve of the streamflows, to
which the “processed”
discharge Q is related.
�Classical design (for high
head plants) foresee a
duration of Qmax of about 2duration of Qmax of about 2
months. The design should
tale into account increases of
construction costs due
increase of Qmax (including
appreciation).
�For small head plants this
value can be increased since
the costs increase rate is
lower.
Estimate of the flow duration curve
�Extended streamflow data series
�Empirical approaches:
- Rainfall data series
- Sporadic streamflow data
- Similar catchments
- Specific contribution of the catchment (Tonini)
�Analytical method: FDC expressed in terms of physical parameters estimated
from hydrologic/climatic/morphologic data
Storage of water when flows are high to compensate the
scarse water availability during low flows
80100120140
Mill
ion m
3/m
onth
Reservoir full (hopefully)
Reservoir management
020406080
Mill
ion m average
Deficit
provided by
storage
Reservoir Dimensioning:long term water balance equation
where Qin represents the natural inflow (result of the
filtering operated by soil moisture on rainfall), Qout is the
sum of the discharge through the spillways and all the other
direct withdrawals (evaporation and direct precipitation are
neglected → catchment area A is much larger than pool
surface S)
Reservoir Dimensioning:deterministic approach for annual management (mid term)
assign Qin deterministically, prescribe Qout, and study the
reservoir volume required to allow for the prescribed
sequence of inflows/outflows
Reservoir Dimensioning:deterministic approach for annual management (mid term)
Hypotheses:
annual regulation (reference period = 1 year; every year is
supposed to produce the same dynamics)
total regulation (all the incoming streamflows are released from
the reservoir at the end of the regulation period of 1 year)
Reservoir Dimensioning:average and typical years
assign Qin during the regulation period in a deterministic manner
(single out deterministic seasonal trends!)
Flow Duration Curves:average and typical years
The same excercise can be done at daily time scale. It depends
on data availability. The longer the time series the better.
1- = Exceedance probability
Q95 = 1.12 m3/s
Global duration curve
Q50 = 3.1 m3/s
Q5 = 7.7 m3/s
Flow Duration Curves:global and average years
Duration curve (average discharge)
Q95 = 1.8 m3/s
Q50 = 3.1 m3/s
Q5 = 7.3 m3/s
1-
Water discharge in the average year
Reservoir volume
Reservoir Dimensioning:cumulated incoming volumes
Average year
Average year
Average year
Reservoir Dimensioning:Regulation volume
Reservoir Dimensioning:Regulation volume
Reservoir Dimensioning:Graphycal representation
Qin is assigned
Qout is constant
Reservoir Dimensioning:Conti representation
“Every line comprised betweenthe input cumulated volume curve(solid red line) and its downwardtranslation of a quantity Vreg(dashed red line) is a potentialcurve of the output cumulatedvolumes compatible with VREG,volumes compatible with VREG,provided that a=b (totalregulation) and its derivative ispositive (Q>0).If this line (e.g. the blue line)touches both the red lines, all theregulation volume is used (i.e. thereservoir is both empty and fullalong the year).”
Example of applicationfor reservoir dimensioning:
excel sheetexcel sheet
Reservoir Management
part of the slides courtesy of Gianluca Botter, part of the slides courtesy of Gianluca Botter,
UNIPD
Constant Hydropower Production (~ 1960)
Mainly Winter Hydropower Production (~ 1970)
To cover the energy demand peakin the cold months and thedecrease of the production of therun-of-river power plant during thesame months.
The derivative of the outputcumulated volume in the wintercumulated volume in the winterperiod represents the maximumflow that can be diverted forhydropower production (accordingto which the design of the powerplant is carried out).
Winter & Summer Hydropower Prod. (~ 2000)
Energy market
Recently: hydropower plants integrate constant-like production
of thermal plants and cover peaks of energy demand
(hydropower plants can be indeed started and stopped easily).
Birth of the energy market
- Anyone can produce, import, buy and sell electric energy
- From July, 1 2007 everybody can buy energy on the market
- From the ENEL monopoly to the free market.... Birth of new
companies for each activity involved in the energy production,
transmission, sale and distribution
TERNA: Property & maintenance of the transmission network
(high/medium voltage)
Energy market
GSE (electric services manager): Management of the
transmission network
ENEL DISTRIBUZIONE + municipal companies: Property &ENEL DISTRIBUZIONE + municipal companies: Property &
maintenance of the distribution network (low voltage)
GME (energy market manager): Management of the electric
energy market
Weekly Trend
Impact on Streamflows
Flood Protection
part of the slides courtesy of Gianluca Botter, part of the slides courtesy of Gianluca Botter,
UNIPD
Conceptual model of a reservoir
a RESERVOIR is made of a DAM with (at least) a crest and aprincipal spillways
Conceptual model of a reservoir
Conceptual model of a reservoir
Conceptual model of a reservoir
Conceptual model of a reservoir
Water balance equation in a reservoir
Water balance equation in a reservoir
FLOOD CONTROL (event scale)
The Reference Flood
The Reference Flood
�Usually centennial rainfall volumes (with different durations)
are generated and empirical or physically based models are
then employed to disaggregate the rainfall and generate the
reference flood wave.
�In general the underlying streamflow volumes are more
relevant than the peakflows to define the behavior of the
reservoir during the flood mitigation.
�The return period of the streamflow volume or of the�The return period of the streamflow volume or of the
peakflow of a given event is obviously different from the return
period of the rainfall event that have generated such event
(soil moisture dynamics!).
�Different events with the same volume may generate
different responses of the reservoir, depending on the shape of
the flood and the initial condition of the reservoir.
An example: a single unregulated spillway
An example: a single unregulated spillway
Selection of site for Hydro-
Electric Production
The following factors should be taken into consideration while
selecting a site for a hydro-electric power plant:
Water Availability.
Record of observations should be acquired for a reasonable
number of years to understand maximum and minimum
variations from the average discharge. Hydrographs and flowvariations from the average discharge. Hydrographs and flow
duration curves can thus be constructed.
In case data are not available, regionalization or stochastic
approach should be adopted.
Distance from Load Center.
Routes and the distances should be carefully considered since the
cost of transmission lines and their maintenance will depend upon
the route selected.
Access to Site
It is always a desirable factor to have a good access to the site ofIt is always a desirable factor to have a good access to the site of
the plant. This factor is very important if the electric power
generated is to be utilized at or near the plant site. The transport
facilities must also be given due consideration.
Water Storage
The output of a hydropower plant is not uniform due to widevariations of incoming streamflow. To have a uniform poweroutput, a water storage is needed so that excess flow at certaintimes may be stored to make it available at the times of lowflow. To select the site of the dam, geological andtopographical studies should be conducted for the design of thefoundations and optimization of the storage volume and headstage.stage.
Head of Water
The level of water in the reservoir for a proposed plant shouldalways be within limits throughout the year.
Hydrodynamic graphGraph showing altitude of the basin as a function of the cumulated drainagearea. Area below curve (hydrodynamic value) is proportional to the potentialenergy available. Useful to design the correct location of a plant, but doesnot have information on streamflow.
Different tributaries
Hydrodynamic graph from DTM
DTM (Digital Terrain Model) is a georeferenced matrix of terrain elevation
north:north: 51575605157560
south:south: 51070005107000
east:east: 16734001673400east:east: 16734001673400
west:west: 16152401615240
rows:rows: 50565056
cols:cols: 58165816
--9999 --9999 --9999 --9999 --9999 --9999
--9999 --9999 --9999 --9999 --9999 --9999
--9999 --9999 --9999 --9999 3088.983088.98 3084.553084.55
--9999 --9999 --9999 3091.483091.48 3088.153088.15 3082.823082.82
--9999 --9999 3090.533090.53 3089.863089.86 3085.863085.86 3079.913079.91
DTM representation
A three-dimensional plot of the DEM of the Fella River Basin [after Rigon, 1994]
Drainage directions
a2
3 4 5
6
Drainage directions of the Fella River Basin
1 78
Network extraction
The effect of different cumulated drainage thresold for the network extraction
(At increases from a) to c)). Plot d) represents the network extracted from
traditional cartography [Tarboton et al., 1989]
GIS Analysis
• http://www.slideshare.net/SlidesAboutHydrology/3-introduction-gis
http://www.slideshare.net/SlidesAboutHydrology/2-hydrogeomorphology
• youtube: http://www.youtube.com/user/udiggis
• Material of Riccardo Rigon’s course
abouthydrology.blogspot.it/2012/02/il-corso-di-idrologia-2012-my-hydrology.html
Hydrodynamic graph
Hydrodynamic graph can be calculated for selected point along the main
channnels.
2350
2450
2550
2650
2750
2850
0 1000000 2000000 3000000 4000000 5000000
Superficie (mq)
Ele
vazio
ne (
m)
s3
s2
s1
Advanced methods for location selection
Analytical method for streamflow + GIS analsys
Advanced methods for location selection
Analytical method for streamflow + GIS analsys
Numerical example:
a single unregulated spillway
Newton method
Matlab implementationMatlab implementation