Clean Currents 2022

Using Load-Sensing Technology to Increase Safety and Reliability of Critical Connections in Hydropower Equipment: Tech Demo 2 in the Innovation Power House

The Bureau of Reclamation has evaluated the use and benefits of using modern sensor technology to monitor the tightness and health of selected threaded connections by using ‘smart’ washers and ‘smart’ bolts that can measure real-time bolt load.

This sensor technology has the potential to easily measure the load on the threaded assembly without having to loosen and re-torque the bolt, giving a direct indication of the health of the fastener.

Reclamation studied selected sensors both in its laboratory and on turbine headcover fasteners on a large hydroelectric generator.

The hands-on demonstration features examples of these ‘smart’ washers.

Background: Why Is Monitoring Needed
In 2009 a hydroelectric accident at the Sayano-Shushenskaya Powerplant in Russia killed 75 people and heavily damaged much of the powerplant. The accident was initiated when the headcover studs on a turbine-generator failed while in service.

Every hydroelectric facility has critical bolted joint connects, which, if were to fail would have the potential to cause catastrophic consequences. Many of these connections are in inaccessible areas making inspection difficult.

A problem with bolted joints is in keeping the threaded assemblies tight and knowing that the installed bolt has the required bolt load. Unequal and insufficient bolt loading is the primary reason for gasket joints to start leaking and bolts to vibrate loose and eventually fail through fatigue. During assembly, bolts can easily be over or underloaded leading to early failure.

The load-sensing technology can be used to monitor the tightness and health of selected threaded connections by using ‘smart’ washers and ‘smart’ bolts that can measure real-time bolt load.

This sensor technology has the potential to easily measure the load on the threaded assembly without having to loosen and retorque the bolt.
View the presentation here.

Presenter Information

John Germann

John Germann
Mechanical Engineer
Bureau of Reclamation, U.S. Department of the Interior
Demonstration Speaker

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