Sel SEL-421 - Trip Output Signals; Manual Trip Logic; Trip Logic Settings and Relay Word Bits

R.1.108
SEL-421 Relay Reference Manual Date Code 20111215
Protection Functions
Trip Logic
setting—see Figure 1.71. See External Recloser on page R.2.27 for additional
information. See TOPD on page A.1.39 for an application example using the
TOP Relay Word bit.
Timer setting TOPD (Trip During Open Pole Time Delay) determines the
period during which any subsequent single-pole trips are converted to a three-
pole trip following the original single-pole trip. To use this feature, include the
Relay Word bit TOP in the E3PT setting.
Trip Output Signals
There are seven Relay Word bits (TPA1, TPA2, TPB1, TPB2, TPC1, TPC2,
and 3PT) that you can program to drive contact outputs to trip circuit breakers.
Relay Word bits TPAn, TPBn, and TPCn are phase-selective tripping signals
for controlling the individual poles of the circuit breakers for single-pole
tripping schemes. Use Relay Word bit 3PT (Three-Pole Trip) to trip all three
poles of both circuit breakers.
Manual Trip Logic
The SEL-421 also has additional logic for manually tripping the circuit
breakers. Use SEL
OGIC control equations BK1MTR and BK2MTR to trip the
circuit breakers manually. Use SEL
OGIC control equations ULMTR1 and
ULMTR2 to unlatch manual trips for Circuit Breaker 1 and Circuit Breaker 2,
respectively.
Trip Logic Settings
and Relay Word Bits
The trip logic settings are shown in Table 1.72 , and the Relay Word bits are
shown in Table 1.73. Some of the settings are only required in certain
situations, as noted.
Table 1.72 Trip Logic Settings (Sheet 1 of 2)
Setting Description Range Default (5 A)
TR Trip SELOGIC Equation M1P OR Z1G
OR M2PT OR
Z2GT
TRCOMM
a
Communications-Assisted Trip SELOGIC Equation (M2P OR Z2G)
AND PLT02
TRSOTF
b
Switch-Onto-Fault Trip SELOGIC Equation 50P1 OR M2P
OR Z2G
DTA Direct Transfer Trip A-phase SEL
OGIC Equation NA
DTB Direct Transfer Trip B-phase SEL
OGIC Equation NA
DTC Direct Transfer Trip C-phase SEL
OGIC Equation NA
BK1MTR Breaker 1 Manual Trip—BK1 SEL
OGIC Equation OC1 OR
PB8_PUL
BK2MTR
c
Breaker 2 Manual Trip—BK2 SELOGIC Equation NA
ULTR Unlatch Trip SEL
OGIC Equation TRGTR
ULMTR1 Unlatch Manual Trip—BK1 SEL
OGIC Equation NOT (52AA1
AND 52AB1
AND 52AC1)
ULMTR2
c
Unlatch Manual Trip—BK2 SELOGIC Equation 1
TOPD Trip During Open Pole Time
Delay (cycles)
2.000-8000 2.000
TULO Trip Unlatch Option 1, 2, 3, 4 3
Z2GTSP Zone 2 Ground Distance Time
Delay
Y, N N