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Hydropower generates electricity using the mechanical energy from large volumes of falling ___.
water
A ___ stops the natural flow of a river, creating a deep reservoir behind it.
dam
Hydro turbines convert water pressure into ___ shaft power.
mechanical
The term 'head' refers to the actual height that ___ through the system.
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Power is the energy converted per second, while energy refers to the total work done for a certain ___.
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For each cubic meter per second of water falling through a 1-meter head, ___ KW of power is generated.
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Hydropower is primarily used to generate ___.
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The category that refers to hydroelectric dams is known as ___ hydroelectric.
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Run-of-the-river hydroelectricity captures the kinetic energy in rivers or streams without a large __________.
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Micro hydro projects provide power to isolated homes, villages, or small __________.
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Pumped-storage hydroelectricity stores water pumped __________ into reservoirs during periods of low demand.
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Power is continuously available as long as there is __________ available.
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The basic formula to calculate power on hydro devices is P = 9,810 __________.
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The turbine efficiency represented in the formula is denoted by the letter __________.
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A micro-hydro turbine with a water input of 40 lps has a flow rate of __________ m3/s.
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The head in the power formula is represented by the letter __________.
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More advanced propeller turbines have blades that can be rotated about their point of attachment to the hub so that they cut the water at different angles depending on the flow rate to the ______.
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The Drive System connects the generator to the ______.
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Direct, one-to-one coupling between the turbine and the generator is the most efficient and dependable ______ system.
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Alternators with brushes are still used for their lower ______.
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Brushless permanent magnet alternators perform higher efficiencies, increasing the hydro system’s ______.
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Utilizing different field configurations, the alternator can produce voltages such as 12V, 24V, 48V, or ______ (3-phase AC).
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Pure AC systems had no batteries or ______.
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Governors and other controls help ensure that an AC generator constantly spins at its correct ______.
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With no load, the generator would 'freewheel' and run at a very high ______.
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DC hydro systems charge their ______ by the generator output.
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A diversion controller is used to manage excess ______ in DC systems.
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Series charge controllers are not used with hydro systems because they cannot operate without a ______.
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Sediment composed of small particles like ______ can cause damage to turbine runners.
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The ______ must be large enough to manage excess flow during floods.
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The settling basin slows down water flow so that silt particles will settle on the basin ______.
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When over-speeding occurs, it can potentially harm the alternator windings and ______.
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The average value of 𝑛 is calculated by adding 0.011 and 0.015 and dividing by ______.
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In Manning’s Equation, the normal depth of flow is influenced by the cross-sectional area ______ and slope.
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A rectangular channel discharges water at a rate of 20 m3/s with a slope of 0.0021, which affects the ______ depth of flow.
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In a hydropower system, the potential energy is based on the penstock head of 40 m and head losses of ______ m.
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A trapezoidal canal section with a total depth of 1.5 m requires a specific ______ width for efficiency.
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For the triangular channel discharging 1m3/s, the normal depth of flow is influenced by the value of ______.
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Hydropower that uses water already diverted for another purpose is a type of ______ hydropower.
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The actual height that water falls through the system is referred to as the ______ head.
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Study Notes
Hydropower
- Hydropower harnesses the mechanical energy of falling water to generate electricity.
- Dams are commonly used to create reservoirs and control water flow for hydropower generation.
- The basic principle of hydropower involves the conversion of water pressure into mechanical energy using turbines.
- The "head" refers to the height of the waterfall in a hydropower system.
- Power is the energy converted per second (rate of work), while energy is the total work done over time.
- 9.8 KW of power is generated for every cubic meter per second of water falling through a 1-meter head.
Types of Hydropower
- Conventional Hydroelectric: Involves using large dams to generate electricity (e.g., Figure 2).
- Run-of-the-River Hydroelectricity: Captures kinetic energy from rivers or streams without a large reservoir, sometimes without dams.
- Small Hydro Projects: Generate 10 megawatts or less and often lack artificial reservoirs.
- Micro Hydro Projects: Provide a few kilowatts to a few hundred kilowatts for isolated homes, villages, or small industries.
- Conduit Hydroelectricity: Utilizes water diverted for other purposes, such as municipal water systems.
- Pumped-Storage Hydroelectricity: Stores water pumped uphill during periods of low demand and releases it for generation during high demand.
Advantages of Hydropower
- Continuous power availability as long as water exists.
- Concentrated energy resource when there is a suitable head.
- Predictable energy availability.
- No imported fuel required.
- Low investment and maintenance costs.
- Minimal technical skills needed for design and installation.
- Long-lasting and robust technology.
Disadvantages of Hydropower
- Site-specific technology.
- Water availability fluctuations limit power output.
- Requires maximum useful power for optimal performance.
Calculating Hydropower
- Power (P) = 9,810 × K × Q × H
- P = Power output (watts)
- K = Turbine efficiency (decimal)
- Q = Water flow rate (m3/s)
- H = Head (meters)
Components of Hydropower Systems
- Turbine: Converts water pressure into mechanical shaft power (e.g., Pelton Wheel, Francis Turbine, Kaplan Turbine)
- Drive System: Connects the generator to the turbine, ensuring optimal turbine speed and generator voltage/frequency.
-
Generator: Converts mechanical energy from the turbine into electrical energy.
- Alternators: Devices with brushes (require regular replacement) or brushless permanent magnets (more efficient and reliable).
- Alternator Configurations: Produce different voltage outputs (12V, 24V, 48V, or 120V) based on field configuration.
-
Controls: Regulate system operation and ensure stable power output.
- AC Controls: Directly use AC generated by the generator.
- DC Controls: Use batteries to store energy, with diversion controllers managing excess energy.
- Settling Basin and Forebay Tanks: Remove sediment from water to prevent damage to the turbine.
- Spillways: Allow controlled overflow and manage excessive water flow during floods.
- Manning's Equation: Used to calculate the normal depth of flow in a channel.
Questions
- Micro hydropower: A type of hydropower generating between 5 kW and 100 kW using natural water flow.
- Turbine: A rotary mechanical device that extracts energy from fluid flow and converts it to useful work.
- Pelton Wheel: A type of turbine that is a refined version of the undershoot wheel.
- Hydropower: Power derived from the energy of falling or running water, harnessed for useful purposes.
- Conduit Hydroelectricity: A type of hydropower that utilizes water already diverted for other uses.
- Head: Refers to the actual height that water falls through in a hydropower system.
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Description
Explore the fundamental principles of hydropower, including how it harnesses the mechanical energy of falling water to create electricity. Learn about different types of hydropower systems such as conventional, run-of-the-river, small hydro, and micro hydro projects, and their unique characteristics.
