Implementing NERC guidelines for coordinating generator and transmission protection

Misoperations of generation protection during the U.S. east coast blackout on August 14, 2003 highlighted the need for better coordination of generator protection with generator capability, generator Automatic Voltage Regulator (AVR) control and transmission system protection. Generator protection misoperations also contributed to the 1996 California blackout. As a result of the 2003 blackouts, NERC (North Electric Reliability Council) has developed a “white paper” entitled “Power Plant and Transmission System Protection Coordination” [1]. The recommendations in the white paper are not yet a NERC standard, but will provide the technical input to producing a standard. This paper will provide practical guidance in implementing NERC-proposed guidelines (as outlined in the NERC white paper) for setting generator protection to coordinate with transmission protection. The paper will also address generator protection security issues that concern NERC that result from low system voltages, relay settings which restrict generator capability under emergency system conditions and coordination of generator protection with generator excitation and governor control.