Schweitzer Engineering Laboratories SEL-352-1 - SEL OGIC Control Equation Analog Compares

5-6 Control Logic Date Code 20010731
SEL-352-1, -2 Instruction Manual
In addition to standard Relay Word bits, fixed logic values are available for SELOGIC control
equations:
ONE (logical 1) or ZERO (logical 0) or NA (logical 0)
If a SEL
OGIC control equation setting is set equal to ONE, it is always “asserted/on/enabled.” If
a SEL
OGIC control equation setting is set equal to ZERO or NA, it is always “deasserted/off/
disabled.”
SEL
OGIC Control Equation Analog Compares
The SEL-352 Relay is capable of interpreting SEL
OGIC control equations that contain a special
type of element, the Analog Compare. Use these elements in any SEL
OGIC control equation in
the same manner as a Relay Word bit, except that the “/” and “\” operators may not be used with
Analog Compares. The Analog Compare outputs a logical 1 when the compare statement is true,
and a logical 0 when it is false. A SEL
OGIC control equation Analog Compare has the following
format:
NAME OP VALUE
where
NAME is one of the valid analog names (see below).
OP is an arithmetic operator (<, <=, >, >=).
VALUE is either a fixed numerical value or another NAME scaled in the same units.
Examples of Analog Compare statements are IA>2.2 or VAX>=VAY. An equation using an
Analog Compare might be written as SAA = IA>2.2 + 50LD, for example. In the Limitations of
SEL
OGIC Control Equations discussion that follows, an Analog Compare counts as two
elements, in determining the size of a SEL
OGIC control equation.
The following is a list of valid SEL-352 Relay analog names and their ranges. The first list is
updated every eighth cycle.
RMS current magnitudes (IRMSA, IRMSB, IRMSC) are only available in the SEL-352-2 Relay.
Table 5.3: Valid Analog Compare Quantities
Name Description
Range
5 A
Range
1 A
Decimal
Places
IMAX, IMIN, IA, IB, IC Phase current
magnitudes
0.1–45 A
(secondary)
0.02–9 A
(secondary)
2
IHA, IHB, IHC Half-cosine filtered
phase current
magnitudes
0.5–45 A
(secondary)
0.1–9 A
(secondary)
2
3I0 Sequence current
magnitudes
0.1–45 A
(secondary)
0.02–9 A
(secondary)
2
VXMAX, VXMIN,
VYMAX, VYMIN, VAX,
VBX, VCX, VAY, VBY,
Phase voltage
magnitudes
1–120 V
(secondary)
1–120 V
(secondary)
1