Blade ressonance x Load x underfrequency protection.

[Ysaac]

I have read that in order to avoid blade ressonace and it´s efects, a steam turbine operating conected to a system must be removed from there if a underfrequency condition is present (for example 58 Hz in a 60Hz system). The books also says that these effects are cumulative.

My question is: in case of a turbine/generator NOT conected to system, providing energy only to its auxiliar service (10% of total load), should the turbine be triped to avoid blade ressonance and it´s efects if the frequency falls to 58Hz or in this level of load there are no trouble?

 

[byrdj]

the large lp units i worked on even avoided maintaining a sub sycronise warming hold speed. the high warming speed hold would ramp and decay over a few minute period to ensure a resonance was not excited. another feature was an automatic speed corrector to bring unit near as possible to synch speed while generator was matched

 

[Ysaac]

thanks everybody