P14x
Restoration
Frequency
Shedding
Frequency
Trip
Underfrequency
Element
Off
Holding
Complete
Timer
Off
Restoration
Complete
Timer
Off
Stage 1 Restore Start
On
Off
On
Stage 1 Restore Enable
Off
V00855
Figure 135: Load restoration with long deviation into holding band
P14xEd1-TM-EN-1
System Frequency
Underfrequency
Underfrequency
Trip Stage (n)
Element Pick-up
Load Shedding
System Frequency
Recovery Starts
Restoration Time Starts
Chapter 11 - Frequency Protection Functions
Time greater than
Holding Timer Setting
Holding
Timer
System Frequency
System Frequency
Partial Decay
Recovery Continues
Restoration Timer
Restoration Timer
Suspended
Resumes Timing
Holding Band
Restoration Time
Completes Stage
(n) Load
Restoration
253