Frequency Event Nadir/Zenith definition

Frequency Event Nadir/Zenith means the point at which the minimum Frequency occurs during the POR period is the minimum/maximum frequency observed in the immediate aftermath of the Significant Frequency Disturbance. The Frequency at this point is referred to as the “Nadir/Zenith Frequency” and the “Nadir/Zenith Time” means is the time at which the Frequency Event Nadir/Zenith occurs;