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Advantages of Using Level and Flow Controls in Surge Tanks and Pump Protection Applications

The generation of hydroelectric power is a complex process, which involves a reservoir that stores water from a natural body of water, a penstock that allows water to flow from the reservoir to a turbine’s propeller and a power station that contains the power generating equipment. Hydroelectric power generation may also involve a dam with containment walls that prevent water from flowing.

Implementing accurate and reliable level and flow controls throughout a hydroelectric plant can keep these processes running smoothly – and protect expensive equipment from being damaged. Here are a few applications where you can take advantage of level and flow controls to enhance your facility’s operations.

Surge Tank
A surge tank controls pressure variations caused by rapid changes in the velocity of water. When a power turbine is running at a steady load, there are no surges in the flow of water because the quantity of water flowing through the conduit is sufficient to meet the turbine’s requirements.

However, when turbine load decreases, the gates of the turbine must be closed to reduce water supply. The excess water is routed to the surge tank for storage to prevent the conduit from bursting. When turbine load increases, water is drawn from the surge tank to meet the increased demand.

A surge tank relies on a level sensor to determine when water stored in the tank should be removed. Some of the most frequently used continuous level controls for this application include guided wave radar like the Eclipse® Model 706 and through-air radar like the R82. For point level control, an ultrasonic level switch is recommended.

Pump Protection
Pumps are used to move water within the hydroelectric power generation process. When a pump operates in a reduced or no-flow condition, it can overheat and rupture the pump’s seal. This can cause a dangerous deviation in process pressure and temperature.

Using a flow switch like the Thermatel® Model TD2 in this application protects the pump from damage if a valve is accidentally closed downstream – or if a leak occurs. The flow switch will activate an alarm and shut down the pump when water flow drops below the minimum rate.

For More Information
To learn more about this topic, please download the Magnetrol® Instruments for Renewable Energy Technology bulletin.