PROTECTION
Protection
4–112
The 889 protection elements are organized in six (6) identical setpoint groups: Setpoint
Group 1 to Setpoint Group 6.
Figure 4-35: Protection Display Hierarchy
Each Setpoint Group has the same protection functions, depending on the relay order
code.
Generator Elements
•
Percent Differential
•
Overall Percent Differential
•
Generator Unbalance (46)
•
Inadvertent Energization (50/27)
•
Loss of Excitation (40)
•
Loss of Excitation (40)
•
Third Harmonic Voltage Difference
•
Offline Overcurrent (50OFL)
•
Overload Alarm
Current Elements
•
Phase Time Overcurrent Protection (51P)
•
Phase Instantaneous Overcurrent Protection (50P)
•
Phase Directional Overcurrent Protection (67P)
•
Neutral Time Overcurrent Protection (51N)
•
Neutral Instantaneous Overcurrent Protection (50N)
•
Neutral Directional Overcurrent Protection (67N)
•
Ground Time Overcurrent Protection (51G)
•
Ground Instantaneous Overcurrent Protection (50G)
•
Ground Directional Overcurrent Protection (67G)
•
Sensitive Ground Time Overcurrent Protection (51SG)
889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS