ODUCTION
One of the most broadly used renewable source of energy for generating electricity on enormous scale is hydropower.
Hydropower is a tremendously flexible technology for power generation. Hydro reservoirs provide built-in energy storage, and the firm response period of hydropower enables it to be used to optimise electricity production across grids, meeting sudden fluctuations in demands.
The power acquired from river or ocean water is called as hydropower.
Hydroelectric power, or electricity, is mostly electrical energy that has been generated using natural forces such as gravity or flowing water. It’s generally produced by dams, since dam can store and direct large volumes of water. Hydroelectric power is becoming increasingly popular.
Hydropower is the renewable source of energy since water is available in large amounts from rain, rivers, and oceans and this is will be available for limitless time to come.
According to the World Energy Council, about33 % of the planet water resources have been developed.
More than 90 % of the available hydropower potential have already
been technologically advanced in France, Switzerland, and Austria.
65 to 90 % – in Japan, Germany, and Sweden,
45 to 65 % – in the USA, Canada, Brazil and Spain,
20-45 % – in China, India, and Argentina.
2. TYPES
i. Water wheels
ii. Hydro power plants
iii. Wave energy from oceans
iv. Tidal energy
v. Dam less hydro power
Based on Quantity of Water Available
Run-of river hydropower plants with pond:
These are hydro power plants that utilize the watercourse flow as it comes, without any storage provided. Run-of-the-river power plants may have no water storage at all or a restricted quantity of storage, in which case the storage reservoir is referred to as poundage. A plant without poundage has no water storage and is, therefore, subject to seasonal river flows. Thus, the plant will operate as an intermittent energy source while a plant with poundage can regulate the water flow at all times and can serve as a peaking power plant or base load power plant.
Storage hydroelectric power plants:
Hydropower plants with storage are supplied with water from large storage reservoir that have been established by constructing dams through rivers. Assured flow for hydro power generation is more certain for the storage systems than the run-of-river systems. Figure-pumped storage hydropower plant.
Based on the Head of Water Available
Low head hydroelectric power plants:
Low head hydro power applications use river current flows of 30 meters or a lesser amount to produce energy. These applications do not need to dam or hold water to form hydraulic head, the head is only a few meters. Using the current of a river or the naturally arising tidal flow to create electricity may afford a renewable energy source that will have a minimal effect on the environment.
Medium head hydroelectric power plants:
The hydro power plants in which the working head of water is between 30 meters but 300 meters are called medium head hydroelectric power plants. These hydroelectric power plant are generally situated in the mountainous sections where the rivers flows at great heights, thus obtaining the high head of the water in dam becomes possible.
High head hydroelectric power plants:
A power station operating under heads above 300m. A head of 200m/250m is measured as the limit between medium and high head power stations.
Based on the Nature of Load
Base load hydroelectric power plants:
The base load type of hydroelectric power plants produce power frequently irrespective of the total load in the national grid. They keep on producing power during the day and all the times of the year. They will halt producing power only during breakdown maintenance.
Peak load hydroelectric power plants:
Most of the usual power requirements are satisfied by the base load hydroelectric power plants. However, during night times the necessity of power turn out to be very high; it is called peak load period. During peak load periods small power plants are started that add to the overall power generated in the grid by base load plants. The peak load plants are not run nonstop since the price of production of power from them is high.
3. PRINCIPLE
WATER CYCLE
The unbroken cycle in which water changes from water vapour in the atmosphere to liquid water through condensation and precipitation and then back to water vapour through evaporation, transpiration, and respiration. This is a natural course that occurs. This natural cycle is very important living organism present on the earth.
WATER CYCLE IN NATURE
Water surface evaporation
Precipitation of clouds
Surface run-off
Collected back to the oceans
Sublimation
Advection
4. STAGES
Hydroelectric dam
There is potential energy deposited in a water reservoir at the rear end of dam. It is changed into kinetic energy when the water begins to flow down the penstock, from the dam. This kinetic energy is used to turn a turbine.
Generator
The subsiding water strikes a series of blades attached around a shaft which transforms kinetic energy to mechanical energy, and makes the turbine to rotate. The shaft is connected to a generator, so that when the turbine rotates, the generator is driven. The generator changes the turbine's mechanical energy into electric energy.
Step-up transformer
Voltage is the force that makes electricity flow. Generators usually fabricated electricity with a low voltage. For the transmission lines to transmit the electricity efficiently over long distances, the low generator voltage is amplified to a higher transmission voltage by a step-up transformer.
Grid high voltage transmission lines
Grid transmission lines, usually supported by giant metal towers, carrying high voltage electricity to long distances.
Terminal Station
Terminal stations control power run on grid transmission lines and decrease the grid voltage to sub transmission voltage.
Sub transmission lines
Sub transmission lines stream power from terminal stations to huge industrial customers or distribution substations.
How it is used by the customer
Electric energy can be traded at transmission voltage to users of enormous amounts who own and function their own substations. Most customers, however, are incapable to accept energy at transmission voltage, and necessitate that it be stepped down in a transformer.
Distribution substation
A distribution substation is a system of transformers, meters, and control and defensive devices. At a substation, transmission voltage is lowered to lower voltages for distribution to domestic, commercial, and small industrial customers.
5. COMPONENT
DAM: –
A dam is a blockade that holds water or underground streams. Reservoirs formed by dams not only holds floods but also provide water for irrigation, human consumption, industrial use, aquaculture and etc. Hydropower is frequently used in combination with dams to generate electricity. A dam can also be used to gather water or for storage of water which can be uniformly distributed between locations. Dams generally assist to the primary purpose of holding water.
Classification of dams
Storage dams
Diversion dams
Detention dams
Overflow dams
Rock fill dams
Gravity dams
I. WATER RESERVOIR: –
Place behind the dam
Height of water
Potential energy
A place to store water
Water later used to produce electricity
• 3-D Representation
• 2-D Representation
II. PENSTROK: –
Gate or opening structure that controls the water flow.
Walled pipe that delivers water to hydro turbines and sewerage structure.
III. IMPELLER OF TURBINE: –
Convert HYDROLIC energy to MECHANICAL energy.
Its main task is to transfer energy.
There are many type of impeller present.
Mainly used are axial flow and radial flow impeller.
They can further have classified into three sub-type:
o Propeller
o Paddles
o Turbines
• 3-D Representation
• 2-D Representation
IV. DYNAMO: –
Convert MECHANICAL energy to ELCTRICAL energy.
It generates direct current, using electromagnetism.
The other term used for dynamo is generator.
Alternator is another part of the dynamo which produces alternating current.
• 3-D Representation
• 2-D Representation
V. TRANSFORMER: –
Converts the alternating current to high voltage current.
Two coils: the supply coil and the outlet coil.
Voltage required for different applications is 110V or 230V.
Numbers of turns in outlet coil are double of supply coil, the voltage produced is also double.
It works with the help of a process called electromagnetic induction.
Used to increase or decrease the alternating voltages in electric power applications.
The two main type of transformer are step-up and step-down transformers.
During transforming of power there is no change in frequency.
VI. TAILRACE: –
Pipeline to drain the water into the river.
The potential energy of water in the tailrace has been used to generate electricity.
Its main use is to supply the water used to rotate the impeller to the natural source of water.
6. Assembly
Here the component assembled are:
o Impeller
o Dynamo
o Water tank
o Shaft
o Support frame
• 3-D Representation
• 2-D Representation (Wire frame)
7. Literature review
• Fluid Mechanics and Fluid Power Engineering
Author: D.S. Kumar
Publisher: S.K. Kataria & Sons
• Fluid Mechanics and Hydraulic Machines
Author: R.K. Rajput
Publisher: S. Chand & Co.
• Fluid Mechanics
Author: Frank.M. White
Publisher: McGraw Hill Publishing Company Ltd
• Power Plant Engineering
Author: P.K. Nag
Publisher: McGraw-Hill Education