Schweitzer Engineering Laboratories, Inc.
SEL-451 Data Sheet
17
SEL
OGIC
Control Equations With
Expanded Capabilities and Aliases
Expanded SEL
OGIC
control equations put relay logic in the
hands of the engineer. Assign inputs to suit your application,
logically combine selected bay elements for various control
functions, and assign outputs to your logic functions.
Programming SEL
OGIC
control equations consists of
combining relay elements, inputs, and outputs with
SEL
OGIC
control equation operators (
). Any ele-
ment in the Relay Word can be used in these equations.
For complex or unique applications, these expanded
SEL
OGIC
functions allow superior flexibility.
Use the relay alias capability to assign more meaningful
names to analog and Boolean quantities. This improves
the readability of customized programming. Use as many
as 200 aliases to rename any digital or analog quantity.
The following is an example of possible applications of
SEL
OGIC
control equations that use aliases.
Add programmable control functions to your relay and
automation systems. New functions and capabilities
enable use of analog values in conditional logic state-
ments. The following are examples of possible applica-
tions of SEL
OGIC
control equations with expanded
capabilities.
➤
Emulate a motor-driven reclose timer, including
stall, reset, and drive-to-lockout conditions (refer
to
➤
Scale analog values for SCADA retrieval.
➤
Initiate remedial action sequence based on load
flow before fault conditions.
➤
Interlock breakers and disconnect switches.
Table 4
Open Communications Protocol
Type
Description
ASCII
Plain-language commands for human and simple machine communications. Use for metering, setting, self-
test status, event reporting, and other functions.
Compressed ASCII
Comma-delimited ASCII data reports. Allows external devices to obtain bay data in an appropriate format for
direct import into spreadsheets and database programs. Data are checksum protected.
Extended Fast Meter,
Fast Operate, and Fast SER
Binary protocol for machine-to-machine communication. Quickly updates
SEL
-2032 Communications
Processors, RTUs, and other substation devices with metering information, bay element, I/O status, time-
tags, open and close commands, and summary event reports. Data are checksum protected.
Binary and ASCII protocols operate simultaneously over the same communications lines so that control oper-
ator metering information is not lost while a technician is transferring an event report.
Ymodem
Support for reading event, settings, and oscillography files.
DNP3 Level 2 Outstation
Distributed Network Protocol with point remapping. Includes access to metering data, protection elements,
contact I/O, targets, SER, relay summary event reports, and settings groups.
IEEE C37.118
Phasor measurement protocol.
IEC 61850 Edition 2
Ethernet-based international standard for interoperability between intelligent devices in a substation.
Table 5
SEL
OGIC
Control Equation Operators
Operator Type
Operators
Comments
Boolean
AND, OR, NOT
Allows combination of measuring units.
Edge Detection
F_TRIG, R_TRIG
Operates at the change of state of an internal function.
Comparison
>, >=, =, <=, <, < >
Arithmetic
+, –, *, /
Uses traditional math functions for analog quantities in an easily programmable equation.
Numerical
ABS, SIN, COS, LN, EXP, SQRT
LOG
Precedence Control
( )
Allows multiple and nested sets of parentheses.
Comment
# (* *)
Provides for easy documentation of control and protection logic.
=>>
SET T <Enter>
1:
PMV01,THETA
(assign the alias “THETA” to math variable PMV01)
2:
PMV02,TAN
(assign the alias “TAN” to math variable PMV02)
=>>
SET L <Enter>
1:
# CALCULATE THE TANGENT OF THETA
2:
TAN:=SIN(THETA)/COS(THETA)
(use the aliases in an equation)
