NERC's Actions in Response to Blackout

PSERC

04/06/04

Recommendation #8

•#8a.: Zone III relays

- Zone III relay should not operate at or below 150% of the emergency power rating of a line assuming .85% p.u. voltage and line phase angle of 30 degrees

- Out of step conditions should not “confuse” the relay

•#8b.: Under-voltage load shedding

-low voltage with both high and low frequencies should be considered

- coordination with generator under- and over-frequency protection and controls

•#8c.: propose revisions to the planning criteria