9
Date Code 20200326
SEL Application Guide 2020-04
PT1
Permissive Trip 1 Equation
RMB1A
Receive a PT from the remote end.
OUT101
Output Contact 101 Equation
TRIP
Trip the output to the circuit breaker.
52A
Circuit Breaker Status Equation
IN101
Assign to the circuit breaker 52a status.
a
Negative-sequence and ground-directional overcurrent elements can be added to the TRCOMM equation, along with the mho
phase- and mho ground-distance elements.
Table 10
SEL-321-1 POTT Logic
Setting
Setting Description
Setting Value
Comment
MTCS
Mask for Trip Communications
Scheme Variable
M2P + Z2G
a
(default)
a
Negative-sequence and ground-directional overcurrent elements can be added to the TRCOMM equation, along with the mho
phase- and mho ground-distance elements.
Elements that allow high-speed communications-
assisted tripping.
TMB1
Transmit Mirrored Bit 1
KEY
Send a PT to the remote end.
RMB1
b
b
Because PROTOCOL = MB, set RMB1 in Global settings.
Receive Mirrored Bit 1
PT
Receive a PT from the remote end.
OUT1
Output Contact Logic OUT1
3PT
Trip the output to the circuit breaker.
IN1
Input Contact 1 Assignment
52A1
Assign to the circuit breaker 52a status.
Table 9
SEL-311C-1 POTT Logic (Sheet 2 of 2)
Setting
Setting Description
Setting Value
Comment
Figure 7
Simplified POTT Logic Between the SEL-421-5 and SEL-311C-1 Relays
TRCOMM
TRIP
PT1
(RMB1A)
Key
(TMB1A)
TRCOMM
TRIP
PT1
(RMB1A)
Key
(TMB1A)
SEL-421-5
SEL-311C-1
Zone 3
3PO
(Three-Pole Open)
Zone 3
3PO
Figure 8
Simplified POTT Logic Between the SEL-421-5 and SEL-321-1 Relays
TRCOMM
TRIP
PT1
(RMB1A)
Key
(RMB1A)
MTCS
TRIP
PT1
(RMB1)
Key
(TMB1)
SEL-421-5
SEL-321-1
Zone 3
3PO
Zone 3
3PO
