Schweitzer Engineering Laboratories SEL-421-4 - Table 5.75 DCUB Relay Word Bits; Figure 5.97 Permissive Trip Received Logic Diagram

5.135
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Directional Comparison Unblocking Scheme Logic
UBDURD: DCUB Disable Delay
This timer prevents high-speed tripping via the POTT scheme logic after a setta-
ble time following a loss-of-channel condition; a typical setting is nine cycles.
Channel 1 and Channel 2 logic use separate timers but have this same delay set-
ting.
UBEND: DCUB Duration Delay
This timer determines the minimum time before the relay declares a loss-of-chan-
nel condition; a typical setting is 0.5 cycles. Channel 1 and Channel 2 logic use
separate timers but have this same delay setting.
Ta b l e 5 .75 DCUB Re l ay Wo rd Bits
Name Description
UBB1 Block permissive trip on Receiver 1
PTRX1 Permissive trip received on Channel 1
UBB2 Block permissive trip on Receiver 2
PTXR2 Permissive trip received on Channel 2
UBB Block permissive trip received on Channel 1 or Channel 2
PTRX Permissive trip received on Channel 1 and Channel 2
Figure 5.97 Permissive Trip Received Logic Diagram
PTRX
Relay
Word
Bit
UBB
UBB1
UBB2
Relay
Word
Bits
ECOMM := POTT
ECOMM := POTT2
PT1
PT1
PT3
SPT
PTA
TPA
SPOA
TPB
SPOB
TPC
SPOC
PTB
PTC
Settings
ECOMM := DCUB2
PTRX1
PTRX2
ECOMM := DCUB1
ECOMM := POTT3
Settings
Relay
Word
Bits
ECOMM := DCUB1
Setting
ECOMM := DCUB2
Setting
Setting
0.25
CYC
0.25
CYC
0
0.25
CYC