HV Motors Protection Settings

[flickstar]

Ladies and Gents,

I am currently investigating protection settings of HV motors across our plant in an attempt to establish some sort of standard practice/guidelines for determining these settings.

I am interested in hearing your protection philosophies. Should settings be based on motor characteristics or fault levels? How do you best trade-off between protecting your equipment and avoiding nuisance tripping? Should different settings be based on different aspects, for example, overcurrent settings based on system fault levels and thermal settings based on motor characteristics?

I am a young engineer and this project is presenting itself as a great learning experience. I would greatly appreciate your collected wisdom!

Thank you.

 

[jbartos]

Suggestions marked ///\\Should settings be based on motor characteristics or fault levels?
///Actually on both. If the protective device cannot clear the fault level, it may explode. Therefore, this aspect is mandatory.
If the protective device cannot protect the motor, the motor may burn.\\ How do you best trade-off between protecting your equipment and avoiding nuisance tripping?
///This may require a trial and error approach to achieve a sensitive protection.\\ Should different settings be based on different aspects, for example, overcurrent settings based on system fault levels
///Yes, this is the industry standard, e.g. IEEE, IEC, etc.\\ and thermal settings based on motor characteristics?
///Yes. Again, this is the industry standard, IEEE, IEC, NEMA, UL, etc.\\\

 

[busbar]

Should the motor {or loss of it} have any significant value, you might review IEEE C37.96-2000 'Guide for AC Motor Protection.' Also: “Alarm and Trip Settings - 3 Phase Induction Motor” thread237-23490 has good detail.

thread237-17349
thread237-15822
thread238-4262
thread237-14282
thread238-22526
thread237-18281
thread237-12394

 

[flickstar]

Thanks jbartos and busbar.