Kaplan Turbine

what is a kaplan turbine ?

A Kaplan turbine is a type of hydroelectric turbine used to convert the energy of flowing water into mechanical energy. It is specifically designed for low-head, high-flow conditions, making it suitable for installations where there is a large volume of water available but the available head (the height difference between the water source and the turbine) is relatively low.


The Kaplan turbine was developed by the Austrian engineer Viktor Kaplan in the early 20th century. It is a propeller-type turbine that consists of a runner with adjustable blades and a spiral-shaped casing. The runner is connected to a shaft, which is in turn connected to a generator to produce electricity.

One of the key features of the Kaplan turbine is its ability to adjust the angle of the blades based on the flow conditions. This allows the turbine to operate efficiently over a wide range of flow rates and maintain a high level of performance even when the water flow varies. The adjustable blades also enable the turbine to operate at different heads, making it versatile for various hydroelectric power generation projects.

The Kaplan turbine is commonly used in run-of-the-river hydroelectric power plants, where the water is diverted from a river or a canal and then returned to the same watercourse downstream. It is also utilized in tidal power installations and other applications that involve large volumes of water with relatively low heads.

Overall, the Kaplan turbine is an efficient and adaptable technology that has played a significant role in the development of renewable energy generation from water resources. Its design allows for optimal utilization of available water resources, making it a preferred choice for hydroelectric power projects worldwide.

Must Read : Hydro Power Plant

kaplan turbine diagram

Kaplan turbine

kaplan turbine parts

The Kaplan turbine consists of several main parts that work together to convert the energy of flowing water into mechanical energy. These parts include:

Kalpan turbine parts
  1. Turbine Shaft: The turbine shaft is a central component that connects the turbine to the generator. It transmits the rotational motion from the turbine to the generator, which ultimately converts the mechanical energy into electrical energy.
  2. Guide Vane: The guide vane, also known as the wicket gate, is located at the entrance of the turbine. It is responsible for controlling the flow of water entering the turbine. By adjusting the position of the guide vanes, the flow rate and direction of the water can be regulated, optimizing the turbine’s performance under different operating conditions.
  3. Runner Vanes: The runner vanes, also called blades or impeller blades, are located within the turbine. These adjustable blades are attached to the turbine shaft and are designed to capture the energy from the flowing water. As the water passes through the runner vanes, its kinetic energy is converted into mechanical energy, causing the turbine shaft to rotate.
  4. Scroll Casing: The scroll casing surrounds the runner vanes. It is a spiral-shaped structure that helps guide the water flow from the guide vanes to the runner vanes, ensuring efficient energy conversion. The scroll casing also helps to increase the pressure on the runner vanes, maximizing power generation.
  5. Draft Tube: The draft tube is a component located at the outlet of the turbine. It provides a smooth transition for the water as it exits the runner vanes. The draft tube helps to maintain a low-pressure environment at the outlet, enhancing the turbine’s efficiency by reducing the pressure difference between the inlet and outlet.
  6. Tail Race: The tail race is the channel or conduit through which the water flows after passing through the turbine. It directs the water back to the natural watercourse, such as a river, canal, or reservoir, downstream of the turbine. The tail race ensures a proper discharge of water from the turbine and maintains the water balance in the system.

These main parts of the Kaplan turbine work in coordination to efficiently harness the energy of flowing water and generate mechanical rotation, which is then converted into electrical energy by the connected generator.

kaplan turbine working principle

The Kaplan turbine operates based on the principle of converting the kinetic energy of flowing water into mechanical energy, and subsequently, into electrical energy.

The process begins with water intake from a water source, such as a river or canal. The flow of water is controlled by adjustable guide vanes, also known as wicket gates, located at the entrance of the turbine. By changing the position of the guide vanes, the flow rate and direction of the water entering the turbine can be regulated. This adjustment optimizes the turbine’s performance under different operating conditions.

Once inside the turbine, the water flows over the runner, which consists of adjustable blades or vanes. The runner blades are attached to a rotating shaft. As the water passes through the runner, the kinetic energy of the water is transferred to the blades, causing the runner to rotate.

The rotational motion of the runner is then transmitted to a turbine shaft, which connects to a generator. The generator converts the mechanical energy from the rotating shaft into electrical energy, producing electric power. The amount of power generated depends on the flow rate and head (the height difference between the water source and the turbine).

After passing through the runner, the water exits through a draft tube. The draft tube provides a smooth transition for the water as it leaves the runner, helping to maintain a low-pressure environment at the turbine outlet. This low-pressure condition improves the turbine’s efficiency by reducing the pressure difference between the inlet and outlet, allowing more energy to be extracted from the flowing water.

Finally, the water is directed into the tail race, which is a channel or conduit that returns the water to the natural watercourse downstream of the turbine.

The operation of the Kaplan turbine can be controlled and adjusted by varying the positions of the guide vanes and runner blades. This allows for optimal performance under different flow conditions and load demands. By adjusting the angle of the guide vanes and the blades, the turbine can maintain high efficiency and adapt to changes in water flow rates and heads.

In summary, the working principle of the Kaplan turbine involves controlling the flow of water with guide vanes, directing it through the runner where kinetic energy is converted into mechanical energy, transmitting the mechanical energy to a generator, and finally, converting it into electrical energy. The adjustable blades and guide vanes enable the turbine to adapt to varying flow conditions, optimizing its performance and making it a versatile and efficient technology for hydroelectric power generation.

applications of kaplan turbine

Kaplan turbines find applications in various hydroelectric power generation projects. Some of the common applications include:

  1. Run-of-the-River Power Plants: Kaplan turbines are widely used in run-of-the-river hydroelectric power plants. These plants are designed to harness the energy of a river’s natural flow without the need for large reservoirs or dams. Kaplan turbines efficiently convert the kinetic energy of flowing water into electricity in low-head, high-flow conditions, making them well-suited for run-of-the-river installations.
  2. Low-Head Dams: Kaplan turbines are commonly used in low-head dam projects. These dams are typically built across rivers or canals with relatively small height differences (head) between the upstream and downstream water levels. Kaplan turbines can effectively capture the energy from the water flow in these low-head conditions and generate electricity.
  3. Tidal Power Generation: Kaplan turbines can be utilized in tidal power generation projects. Tidal energy involves capturing the kinetic energy of tidal currents as the tides rise and fall. Kaplan turbines can be installed in tidal barrages or channels to harness the tidal flows, converting them into electricity. Their adjustable blades allow them to operate efficiently in both ebb and flood tide conditions.
  4. Diversion Canals: Kaplan turbines are suitable for power generation in diversion canals. Diversion canals are constructed to divert water from a river or reservoir to supply irrigation systems, water treatment plants, or other water distribution networks. Kaplan turbines can be installed in these canals to extract energy from the flowing water and generate electricity while still serving their primary purpose of water diversion.
  5. Industrial Applications: Kaplan turbines can also be used in industrial settings where there is a need to harness energy from flowing water for specific applications. For example, they can be used to generate electricity from wastewater treatment plants, where the water flows with a relatively low head but high volume.
  6. Hydropower Upgrades: In existing hydropower facilities, Kaplan turbines can be employed as an upgrade or replacement for older, less efficient turbines. By retrofitting with Kaplan turbines, the power generation capacity and efficiency of the facility can be improved without significant changes to the existing infrastructure.

Overall, the versatility and adaptability of Kaplan turbines make them suitable for a range of hydroelectric power generation applications, particularly in low-head, high-flow conditions.

advantages of kaplan turbine

The Kaplan turbine offers several advantages, which have contributed to its widespread use in hydroelectric power generation. Some of the advantages of Kaplan turbines include:

  1. High Efficiency: Kaplan turbines are known for their high efficiency in converting the energy of flowing water into mechanical energy. Their adjustable blades allow for optimal performance across a wide range of flow rates and heads. This efficiency translates into a higher power output for a given amount of water, maximizing the energy conversion process.
  2. Versatility: Kaplan turbines are versatile and can operate effectively in both low-head and high-flow conditions. They can accommodate a wide range of water flow rates, making them suitable for various hydroelectric projects. This adaptability allows for the utilization of a greater number of potential sites for power generation.
  3. Compact Design: Kaplan turbines have a compact design, which makes them suitable for installations where space is limited. Their smaller size allows for easier integration into existing water infrastructure, such as rivers, canals, or dams.
  4. Variable Blade Pitch: The adjustable blades of Kaplan turbines can be rotated to optimize the performance under different flow conditions. This feature allows the turbine to maintain high efficiency across a range of water flow rates, ensuring consistent power generation even as the flow of water changes.
  5. Improved Fish Passage: Compared to some other types of turbines, Kaplan turbines can be designed with features that improve fish passage. Fish-friendly designs can be incorporated into the turbine to minimize the impact on fish and aquatic organisms, reducing the risk of injury or mortality during their migration.
  6. Durability: Kaplan turbines are built to withstand the harsh conditions of hydroelectric power generation. They are typically constructed with robust materials and designed for long-term operation, ensuring durability and reliability.
  7. Rapid Response to Load Changes: Kaplan turbines have the capability to respond quickly to changes in the electrical grid’s load demand. This responsiveness allows for efficient and effective integration of the turbine into the power system, helping to maintain grid stability.

Overall, the high efficiency, versatility, compact design, and other advantages of Kaplan turbines make them a preferred choice for many hydroelectric power projects. Their ability to adapt to varying flow rates, coupled with their durability and fish-friendly design options, contribute to their popularity in sustainable energy generation.

disadvantages of kaplan turbine

While the Kaplan turbine offers several advantages, it also has a few disadvantages that should be considered. Some of the drawbacks of Kaplan turbines include:

  1. Complex Design and Maintenance: Kaplan turbines have a more complex design compared to other types of turbines. They require precise engineering and maintenance, which can increase the overall cost and complexity of installation and operation. The adjustable blade mechanism adds an additional level of complexity, requiring regular inspection and potential repairs.
  2. Susceptibility to Sediment and Debris: Kaplan turbines are more susceptible to damage caused by sediments and debris in the water. If the water source contains high levels of sediment or if debris such as sticks, logs, or rocks enter the turbine, it can lead to clogging, abrasion, and damage to the blades and other components. Regular maintenance and cleaning are necessary to prevent such issues.
  3. Environmental Impact: Like other hydroelectric turbines, Kaplan turbines can have environmental impacts. The construction of dams or diversion structures required for the installation of Kaplan turbines may alter the natural flow patterns of rivers or disrupt aquatic habitats. Additionally, the turbine blades can pose a risk to fish and other aquatic organisms, particularly if appropriate fish protection measures are not implemented.
  4. Limited Applicability: Kaplan turbines are most suitable for low-head, high-flow conditions. They may not be as efficient or cost-effective in locations with high heads or low flows. Therefore, their applicability is limited to specific sites where these conditions are met.
  5. Turbulence and Noise Generation: The operation of Kaplan turbines can create turbulence and noise in the water, which may have negative effects on the aquatic environment, especially in sensitive ecosystems. These disturbances can potentially disrupt the natural behavior and migration patterns of fish and other aquatic species.

Despite these disadvantages, Kaplan turbines remain a popular choice for hydroelectric power generation in appropriate conditions. Ongoing advancements in design and technology aim to mitigate these drawbacks and improve the overall performance and environmental impact of Kaplan turbines.

difference between kaplan and francis turbine

Certainly! Here is a table highlighting the main differences between Kaplan and Francis turbines:

Kaplan TurbineFrancis Turbine
TypeAxial Flow TurbineMixed Flow Turbine
ApplicationLow to Medium HeadMedium to High Head
Runner DesignPropeller-like bladesCurved blades
Blade AdjustmentBlades are adjustable in pitch angleBlades are fixed and non-adjustable
EfficiencyHigher efficiency at low flow ratesHigher efficiency at high flow rates
Flow ControlPrimarily governed by the adjustable bladesPrimarily governed by the guide vanes
Operating RangeBest suited for wide flow rate variationsBest suited for a relatively narrow flow rate range
Size RangeUsually larger in sizeAvailable in a wide range of sizes
Water FlowHandles a large volume of water with low headHandles a moderate volume of water with high head
CostGenerally more cost-effective due to simpler designGenerally more expensive due to complex construction
MaintenanceRelatively easier maintenance and repairMay require more complex maintenance due to design
Application ExamplesRun-of-river, low-head hydropower installationsHigh-head hydropower plants, pumped storage applications

Please note that this table provides a general overview of the differences between Kaplan and Francis turbines. Specific design variations and advancements may result in further differentiating factors.

Reference : https://en.wikipedia.org/wiki/Kaplan_turbine

Leave a Reply

Your email address will not be published. Required fields are marked *