PROTECTION
Protection
4–138
The 845 protection elements are organized in six (6) identical setpoint groups: Setpoint
Group 1 to Setpoint Group 6.
Figure 4-45: Protection Display Hierarchy
Each Setpoint Group has the same protection functions, depending on the relay order
code.
Transformer Elements
•
Percent Differential
•
Transformer Overload
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)
•
Restricted Ground (Earth) Fault (87G)
•
Negative Sequence Time Overcurrent Protection (51_2)
•
Negative Sequence Instantaneous Overcurrent Protection (50_2)
Voltage Elements
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS