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MICRO HYDROELECTRIC POWER PLANT WITH CHAIN TURBINE
Nguyen Minh Duy
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Content
Overview about hydroelectric power plant
Analysis chain turbine
Governor using for chain turbine
Work in the future
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Hydropower to Electric Power
Potential
Energy
Kinetic
Energy
Electrical
Energy
Mechanical
Energy
Electricity
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Hydropower to Electric Power
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How Hydropower Works
Water from the reservoir flows due to gravity to drive the
turbine.
Turbine is connected to a generator.
Power generated is transmitted over power lines.
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How Hydropower Works (2)
A water turbine that cover the energy of flowing or falling
water into mechanical energy that drives a generator, which
generates electrical power. This is a heart of hydropower power
plant.
A control mechanism to provide stable electrical power. It is
called governor.
Electrical transmission line to deliver the power to its
destination.
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Vietnam Hydroelectric Potential
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Vietnam Hydroelectric Potential (2)
Vietnam, the nation yearly average of rainfall is about
1,861mm.
There are more than 2,200 big-to-small rivers and streams. So
Vietnam is rich hydropower resource.
Vietnam is agricultural country (agriculture: 20.1%). This is a
goal to invest SHP.
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Sizes of Hydropower Plants
Pico hydroelectric plantUp to 10kW, remote areas away from the
gridMicro hydroelectric plant Capacity 10kW to 300kW, usually
provided power for small community or rural industry in remote
areas away from the gridSmall hydroelectric plant Capacity 300kW to
1MWMini hydroelectric plant Capacity above 1MWMedium hydroelectric
plant15 - 100 MW usually feeding a gridLarge hydroelectric
plantMore than 100 MW feeding into a large electricity grid
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Micro Hydropower Systems
Many creeks and rivers are permanent, they never dry up, and these
are the most suitable for micro-hydro power production Micro hydro
turbine could be a waterwheelNewer turbines : Pelton wheel (most
common)Others : Turgo, Crossflow and various axial flow
turbines
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Turbine Classified
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Impulse Turbines
Uses the velocity of the water to move the runner and discharges to
atmospheric pressure.The water stream hits each bucket on the
runner. High head, low flow applications. Types : Pelton turbine,
Turgo turbine
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Pelton Turbine
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Turgo Turbine
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Reaction Turbines
Combined action of pressure and moving water. Runner placed
directly in the water stream flowing over the blades rather than
striking each individually.Lower head and higher flows than
compared with the impulse turbines.
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Francis Turbine
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Kaplan Turbine
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Turbine Selection Chart
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Chain Turbine
It is a gravity machineIt is built up of two parallel chain systems
joint together at the chains with a series of buckets. The flow
rater entering the buckets is controlled by the water valve through
a motor to open or close the valve. Buckets fill full of water go
down to bring to rotary sprocket system.
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Analysis of the Chain Turbine
With flow rate is 1m3/s, and the head is 20m.Assume H1=19m, H2=1m,
the diameter of the sprocket is 1m.
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Analysis of the Chain Turbine (2)
The gross power output:Apply the principle of work and energy with
the bucket of chain turbine:The maximum speed of bucketThe angular
velocity the sprocket would beThe rotational speed of the sprocket
would be
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Analysis of the Chain Turbine (3)
Number of buckets in chain turbineNumber of buckets The volume of a
bucket (m3)80.50100.40120.36
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Analysis of the Chain Turbine (4)
The power output is The power out of the turbine shaftThe
efficiency of the chain turbine is given by
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Analysis of the Chain Turbine (5)
Rotational velocity of sprocket depends on the distance of between
two shafts of turbine H1. Rotational velocity of turbine shaft is
slow, so it cannot directly connect with generator. It need a power
transmission Efficiency of chain turbine is low.
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Advantages of Chain Turbine
It is run-of-river power plant.Do not worry about the turbidity of
water.There is no danger of cavitations.It is simple to construct,
repaired and maintenance.
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Disadvantages of Chain Turbine
The slow rotation of chain turbine leads to high speed ratios when
connect to generator at 600 rpm 1500 rpm.This chain turbine
operation is very noise.Structure of turbine is very big
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Governor
To maintain the generator at a constant 50Hz frequency, it is
necessary to maintain the generator shaft at a constant rotational
speed. In the independent hydroelectric power plant, the rotational
speed of the micro hydro power generator can be change when loads
are added or subtracted from the electrical system.
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Governor (2)
The system frequency can be maintained constant by eliminating the
mismatch between generator and load. Governor is to receipt the
frequency signal from the output of generator. And it is compared
with standard frequency signal. From these results, governor output
signal is coming-out to control the valve of water at the entrance
to the turbine.
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Transfer Function Block Diagram of Hydro Plant
power system gain constant (Hz/p.u)nominal starting time of water
in penstock (s) integral gain constant for servo system
proportional gain controller constant for servo motor
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Governor Transfer Function
Chain Turbine transfer function water starting time at full load So
transfer function of chain turbine is
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Generator Transfer Function
Assume nominal loadFrequency 50HzThe latter load assumption
yieldsSo, the system gain constant and time constant are given
byThe transfer function of generator
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Transient responses of system for step changes in load, showing
deviations in system frequency
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Transient responses of system for step changes in load, (1.5kW)
for different integral gain value, showing deviations in system
frequency (1)
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Transient responses of system for step changes in load, (1.5kW)
for different integral gain value, showing deviations in system
frequency (2)
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Transient responses of system for step changes in load, (1.5kW)
for different integral gain value, showing deviations in system
frequency (1)
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Transient responses of system for step changes in load, (1.5kW)
for different integral gain value, showing deviations in system
frequency (2)
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Governor Discussion
It is more flexible than classical governor.This governor
effectively eliminate the frequency deviations due to load
disturbances for different nominal loadings of the systemIt is
importance as the saved water can be used for irrigation.
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Work in the Future
In China, YiuHwa Engineering Company is building a hydroelectric
power plant with chain turbine to experiment and research with
capacity 200kW. This plant has two turbines and built with head 20m
and flow rate 1.03m3/sec
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