Damping coeffcient

[kssschsekhar]

I found the following information in transmission grid code that

Generator Excitation Control System
???Control performance of the voltage control loop shall be such that under isolated operation conditions the damping?coefficient shall be above 0.25 for the entire operating range.

Could anybody suggest the best book to explain damping coefficient for voltage variations?

Is there any standard code for this ratio? Why 0.25 is selected why not 0.1?

 

[electricpete]

I believe damping coefficient would be a characteristic of the eigenvalues obtained by analysing the entire islanded system.

The definition of damping factor of an eigenvalue is the (negative of the )real part of the eigenvalue over the magnitude of the eigenvalue. Therefore ranges from 0 to undamped to 1 for critically damped.

There may be a more practical expression in terms of voltage control parameters that I am not aware of.

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[electricpete]

fwiw: References for eigenvalue analysis - I believe this would be about any book on power system stability. I know it is well covered in "POWER SYSTEM STABILITY AND CONTROL" by P. KUNDUR coordinated by EPRI and published by McGraw Hill

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[kssschsekhar]

Hi Electricpete

thank you for the information