|Hydro Power plant|
The purpose of this experiment is to study the constructional details and working principle of hydropower plant.
|Principle of Hydro Power Plant:|
- A generating station which utilizes the potential energy of water at a high level for the generation of electrical energy is known as hydro-electric power station. As we know that the power plant is defined as the place where power is generated from a given source, so here the source is hydro that‟s why we called it “hydro power plant”
- The term “hydro‟ is the Greek word for water and hydro power is the energy contained in water.
- Hydro power is considered a renewable energy source.
- Hydro power transform the potential energy of a mass of water flowing in a river or stream with a certain vertical fall (termed the “head”).
- The power output from the scheme is proportional to the flow and to the head.
- The water or hydraulic turbines converts this kinetic and potential energy into mechanical power and is thus a prime mover, which coupled to a generator, produces electrical power. The power plants designed to produce electric power from water, flowing continuously under pressure are known as “hydro-electric power plants”.
The hydro Power plant plays very important role in development of the country as it provides power at cheapest rate as source of natural energy. About 20% of the total world power is generated by hydro Power station. As on the date about 23% of energy is contributed by hydro power to India. The main source of hydroelectricity is the water which is readily available in India. Hydroelectric power defines the usage of water resources towards inflation free green energy in the absence of fuel cost with mature technology characterized by highest prime moving efficiency and operational flexibility. Reservoir hold lots of water which is employed to generate power by means of turbines.
We start to generate electricity from hydro power in 1882 when United States (US) establishes a first hydro power station which generate 12.5 kilowatts (KW) of power. The rapid growth of hydro power comes in 1900‟s when hydraulic reaction turbine comes in picture as a result in 1900‟s hydro power plants fulfill the requirement of 40% of total United states‟ electricity.
For construction of hydro power plant first we choose the area where the water is sufficient to reserve and no crisis of water and suitable to build a dam. The main function of dam is to stop the flow of water and reserve the water in reservoir. Mainly dam is situated at a good height to increase the force of water. Reservoir hold lots of water which is employed to generate power by means of turbines. To control the pressure of water means increase or decrease water pressure whenever required, we use a valve. After that we employ turbine and generator turbine is the main stuff, when water comes through the pen stock with high kinetic energy and falls on turbine blades, turbine rotates at high speed. As we know that the turbine is an engine that transfers energy of fluid into mechanical energy which is coupled with generator converts mechanical energy into electrical energy which we utilized at the end.
In hydro power plant we also add switchgears and protections which control and protect the whole process Inside the Plant. We use step up transformers to enlarge the level of Voltage (generally 132KV, 220KV, 400KV, and above) as per our requirement. After that we transmit the electric power to the load and then we step down the voltage for industrial and large consumer and then again we step down the voltage to distribute electricity at domestic level which we used at home.
This is the whole process of generating electricity by the means of hydro (hydro power plant) and then transmitting and distributing electricity.
In a hydro power plant, the water is collected across the river by constructing a dam. The water from dam is passed through the pipes to turbines. The water coming out of nozzle at high velocity strikes on the blades mounted on the wheel (turbine) where the kinetic energy of water is converted into mechanical energy as it‟s.
For construction of hydro power plant first we choose the area where the water is sufficient to reserve and no crisis of water and suitable to build a dam. The main function of dam is to stop the flow of water and reserve the water in reservoir. Mainly dam is situated at a good height to increase the force of water. Reservoir hold lots of water which is employed to generate power by means of turbines. Penstock, the pipe which is connected between dam and turbine blades and most important purpose of the penstock is to enlarge the kinetic energy of water that‟s why this pipe is made up of extremely well-buildmaterial which carry on the pressure of water. To control the pressure of water means increase or decrease water pressure whenever required, we use a valve. the turbine is an engine that transfers energy of fluid into mechanical energy which is coupled with generator converts mechanical energy into electrical energy which we utilized at the end.
Fig. 1: Principle of Hydroelectric Power plant
Fig.2: System of the Hydro Power plant
|Components of hydro-electric power plant|
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 suitable place.
Whole of water available from the catchment area is collected in the reservoir behind the dam.
Function : To store the Water during rainy season and supply the water during dry season.
A dam is built across a river.
Function : To increase the height of water level behind it which ultimately increases the reservoir capacity.
Function : To prevent the entry of debris which might damage the fixed Blades and runner of turbine or chock up the nozzles of the impulse Turbine.
These are a kind of storage tanks which are present at end of the Head race pipe or canal. These are input to the pen stock.
Function : To serve as a regulating reservoir, temporarily storing water When the load on the plant is reduced and provides water for initial Increment of an increasing load while water in the canal is being accelerated.
Function : It provides better regulation of water in the system during Variable load conditions.
Function : To carry water under the pressure from the large reservoir to the turbine. It‟s pipes of large diameters and commonly made of steel through reinforced concrete. These are input to the penstock.
Function : To discharge major floods without damage to the dam and same time keeps the reservoir level below predetermined maximum level, therefore it considered safety valve for dam.
Turbine ( Prime Mover )
Function : To convert the kinetic energy of water into mechanical energy to produce electric energy.
It is used to produce electricity from turbine mechanical energy. There are various type of generator used in hydro plant like synchronous generator, D.C. generator and Induction generator.
Function : The power house consists of substructure to support the Hydraulic and electric equipment and superstructure to house and protect this equipment.
The draft tube is essential part of reaction turbine.
Function : To discharge water from exit of turbine to tail race.
It is a passage for discharging water leaving the turbine or draft tube into the river.
|Formula For A Hydroelectric Power And Energy & Efficiency|
P = power (KW)
E = energy (KWH)
Q = discharge ( m3 /s)
𝐻𝑔 = gross head (m)
e = overall unit efficiency (%)
e = (ℎ𝑦𝑟𝑙𝑖) ×(𝑟𝑖) ×(𝑔𝑟𝑟)
Overall efficiency = power available at the shaft / Power available at Water jet
= shaft power / water power
= P / WQH
H – Is the net or efficiency head in meters and Q is the total Discharge in m3/s
- A proven hydro power plant library to be provided, which should comprise of the following component models as a minimum.
- Reservoir- should be possible to parameterize to any geometrical shape, can be discretized, and wave propagation due to transients should be covered.
- Head Race Tunnel – should be possible to parameterize to any geometrical shape.
- A pipeline model using a TLM (transmission line modelling) approximation to wave propagation in pipes, penstocks and general closed condition.
- Surge Shaft – Should include a surge shaft connected to multiple penstocks.
- Penstock- Should include penstocks supplying multiple turbines connected in parallel, elastic & inelastic water column effects, water hammer, travelling wave effect to be covered.
A. Calculation of the Turbine Efficiency
The requirement of the data to calculate turbine efficiency and calculation will be write to the observation table given below:
|Measurement No:||Initial time T1||Final time T2|
|Rotation speed of turbine shaft(rev/s)|
|Water flow rate(m3/h)|
|Water inlet pressure(bar)|
Calculation: Using the appropriate equations, calculation the overall Efficiency.
B. Change the turbine efficiency with respect to flow rate:
The necessary data for understanding how turbine efficiency alters when the flow rate is varied and calculations will be recorded to the Observation table given below:
|Measurement No:||Rate, R1||Rate, R2||Rate, R3|
|Rotational speed of turbine shaft(rev/s)|
Calculation: Using the appropriate equations, calculate the efficiency of turbine and draw the graph of efficiency versus flow Rate.
C. Calculation of the generator efficiency:
The necessary data for understanding how calculate generator efficiency and calculation will be recorded to the observation table given below:
|Measurement No||Initial time T1||Initial time T2|
|Water flow rate(m3/h)|
|Water inlet pressure(bar)|
Calculation: Using the appropriate equation, calculation the efficiency of generator.
1) Draw general layout mentioning essential components of hydro Power plant.Explain the function of each components.
2) Classify the Hydro-electric power plants according to availability of head, Quantity of water and nature of load.
3) List the factors affecting selection of site for hydro-electric power plant.