Generator protection : Loss Of Field 1

[ZapSib]

G'Day,

I am dealing with setting schedule for generator protection.
For LOF (ANSI 40) one customer request to get the protection locus among the P/Q capability diagram.

What I get used to is to compute and draw the characteristic within the R/X diagram.

Do you have experience with the P/Q diagram for LOF?
Any reference to share regarding LOF and P/Q diagram?

Thank you.

 

[dpc]

I believe J. L. Blackburn's Protective Relaying book covers translation between P/Q and R/X representations.



David Castor

http://www.cvoes.com

 

[ZapSib]

Thank you David.
I will refer to Blackburn when back in Office.
Is such kind of drawing usual in US ?

Regards.

 

[dpc]

Generally the generator manufacturer provides a P-Q diagram. The relays are usually set by R-X, so sometimes we have to correlate the two.



David Castor

http://www.cvoes.com

 

[Runsor]

Here's an example of a rotor winding failure i.e. a total loss of excitation. This is from a real fault of an 18 MVA generator. Just the P, Q and f were recorded with 50 samples per second. There is no change in the active power at the moment the field diappears!

http://files.engineering.com/getfil...500-f248c6e16a7f&file=RotorWindingFailure.ppt