Mechanical vs Electronic overspeed protection.

[21121956]

Hello everybody:

The debate over Mechanical Overspeed vs. Electronic Overspeed protection is still over the discussion table.

I understand what Electronic Overspeed protection is and how it differs from the traditional Mechanical Bolt Overspeed protection. The specialized literature addresses the issue of electronic overspeed protection, primarily oriented for use in steam turbines.

My concern is, is it reliable to use this protection in hydraulic turbines?
What are the pros and cons of these systems when used in hydraulic turbines?
Thanks in advance for your comments.


El que no puede andar, se sienta.

 

[JJPellin]

I see no reason to differentiate hydraulic turbines as different than steam turbine in this regard. I would always prefer electronic overspeed trip protection. Properly designed, installed and maintained, it should be more reliable (trips which it should), less buggy (does not trip when it shouldn't) and easier to test (simulated trips rather than actually running to overspeed). It should have better redundancy and self-diagnostics.

Johnny Pellin

 

[21121956]

Hello everybody:

Thank you Johnny for your valuable point of view.

El que no puede andar, se sienta.

 

[snoopnoon]

On some of the older machines that originally came with the overspeed bolt but have been upgraded to modern electronic trip (preferred) the bolt is tightened down to trip above the electronic trip speed to act as a last resort safety measure.

 

[hicjy]

Electronic Overspeed protection monitor prober not only one,generally everyturbine have 3 probers,so this protection reliability is very high

 

[ScottyUK]

The large sets I worked with until recently used three overspeed trips: an electronic trip built in to the control system which would attempt recovery of the machine by opening the extraction valves and slamming the governors shut, backed up by an independent hardwired electronic trip which closed the main stop valves by dumping the electro-hydraulic pressure back to tank, plus a 'last ditch' mechanical overspeed bolt which also dumped the E-H pressure. Usually the control system caught a full load rejection event if the governors were correctly calibrated, but I've seen both the backups operate for real when things went wrong.