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13.12
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
SEL
OGIC
Control Equation Programming
SEL
OGIC
Control Equation Elements
Latch Bits
Latch bits are nonvolatile storage locations for Boolean information. Latch bits
are in several settings areas of the relay, as shown in
. Latch bits have
two input parameters, Reset and Set, and one Latched Value, as shown in
Example 13.5
SEL
OGIC
Control Equation Math Variables
The equations below show freeform SEL
OGIC
control equation program-
ming examples that use SEL
OGIC
control equation math variables using ana-
log quantities available in the SEL-421. Each line has a comment after the #
that provides additional description.
PMV01 :=
378.62
# Store 387.62 in PMV01
PMV09 :=
5 + VAFM
# Store sum of 5 and A-Phase voltage in kV in
PMV09
You can use SEL
OGIC
control equation math variables more than once in
freeform programming. Use AMV010 in the following SEL
OGIC
control
equations to calculate intermediate results.
# Determine if any phase voltage is greater than 13 kV
# A-Phase
AMV010 :=
VAFIM/1000
# VA in kV
ASV010 :=
AMV010 > 13
# Set if greater than 13 kV
# B-Phase
AMV010 :=
VBFIM/1000
# VB in kV
ASV011 :=
AMV010 > 13
# Set if greater than 13 kV
# C-Phase
AMV010 :=
VCFIM/1000
# VC in kV
ASV012 :=
AMV010 > 13
# Set if greater than 13 kV
# Combine phase results
ASV013 :=
ASV010 OR ASV011 OR ASV012
Table 13.7
Latch Bit Quantities
Type
Typical
Quantity
Name Range
Protection freeform latch bits
32
PLT01–PLT32
Automation latch bits
32
ALT01–ALT32
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