R.1.62
SEL-421 Relay Reference Manual Date Code 20111215
Protection Functions
Zone Time Delay
The example below uses independent timing for Zone 2 phase and ground
distance protection:
TR := M1P OR Z1G OR M2PT OR Z2GT
Common Zone Timing
Use Relay Word bits ZnT (Zone n Distance Protection) to select common
zone timing in SEL
OGIC control equation TR (Trip) (n = 1–5).
The next example uses common timing for Zone 2 distance protection:
TR := M1P OR Z1G OR Z2T
If the timer input drops out while timing, the relay suspends the common zone
timer for one cycle. This feature prevents resetting the timer when a fault
evolves (e.g., the fault changes from a single phase-to-ground to phase-to-
phase-to-ground). If the timer expires, the relay blocks the suspend-timing
logic.
Table 1.48 Zone Delay Settings
Name Description Selection
Default
(5 A)
Phase Distance
a
a
Independent.
Z1PD Zone 1 Time Delay (cycles) OFF, (0.000–16000) 0.000
Z2PD Zone 2 Time Delay (cycles) OFF, (0.000–16000) 20.000
Z3PD Zone 3 Time Delay (cycles) OFF, (0.000–16000) 60.000
Z4PD Zone 4 Time Delay (cycles) OFF, (0.000–16000) OFF
Z5PD Zone 5 Time Delay (cycles) OFF, (0.000–16000) OFF
Ground Distance
a
Z1GD Zone 1 Time Delay (cycles) OFF, (0.000–16000) 0.000
Z2GD Zone 2 Time Delay (cycles) OFF, (0.000–16000) 20.000
Z3GD Zone 3 Time Delay (cycles) OFF, (0.000–16000) 60.000
Z4GD Zone 4 Time Delay (cycles) OFF, (0.000–16000) OFF
Z5GD Zone 5 Time Delay (cycles) OFF, (0.000–16000) OFF
Distance Elements
b
b
Common.
ECDTD Distance Element Common Time Delay Y, N N
Z1D Zone 1 Time Delay (cycles) OFF, (0.000–16000) 0.000
Z2D Zone 2 Time Delay (cycles) OFF, (0.000–16000) 20.000
Z3D Zone 3 Time Delay (cycles) OFF, (0.000–16000) 60.000
Z4D Zone 4 Time Delay (cycles) OFF, (0.000–16000) OFF
Z5D Zone 5 Time Delay (cycles) OFF, (0.000–16000) OFF
Table 1.49 Zone Time Delay Relay Word Bits (Sheet 1 of 2)
Name Description
M1PT Zone 1 phase distance, time delayed
M2PT Zone 2 phase distance, time delayed
M3PT Zone 3 phase distance, time delayed
M4PT Zone 4 phase distance, time delayed
M5PT Zone 5 phase distance, time delayed
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