Sel SEL-451-5 User manual

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
Key Features and Benefits
The SEL-451-5 Protection, Automation, and Bay Con-
trol System integrates bay control for breakers and dis-
connect switches with full automation and protection in
one device.
➤Protection. Customize distribution protection with
multiple instantaneous and time-overcurrent
elements with SELOGIC®control equations. Best
Choice Ground Directional Element®logic
optimizes directional element performance and
eliminates the need for many directional settings.
Provide comprehensive protection for two breakers
with one relay.
➤Commissioning. Rapidly commission your Bay
Control with preconfigured bay arrangements.
Choose among different bus configurations,
including single- and dual-busbar, transfer bus, tie
breaker, breaker-and-a-half, ring-bus, double-
bus/double-breaker, and source transfer
configurations. These bus arrangements allow easy
status and control of as many as ten disconnect
switches and two breakers. Additional user-
selectable bay types are available via
ACSELERATOR QuickSet®SEL-5030 Software
that can be downloaded at selinc.com.
➤Automation. Take advantage of enhanced
automation features that include 32 programmable
elements for local control, remote control,
protection latching, and automation latching. Local
metering on the large format front-panel LCD
eliminates the need for separate panel meters.
Serial and Ethernet links efficiently transmit key
information, including metering data, protection
element and control input/output (I/O) status, IEEE
C37.118 Synchrophasors, IEC 61850 Edition 2
GOOSE messages, Sequential Events Recorder
(SER) reports, breaker monitor, relay summary
event reports, and time synchronization. Apply
expanded SELOGIC control equations with math
and comparison functions in control applications.
Incorporate as many as 1000 lines of automation
logic to speed and improve control actions.
➤Software-Invertible Polarities. Invert individual
or grouped CT and PT polarities to account for
field wiring or zones of protection changes. CEV
files and all metering and protection logic use the
inverted polarities, whereas COMTRADE event
reports do not use inverted polarities but rather
record signals as applied to the relay.
➤Synchrophasors. Make informed load dispatch
decisions based on actual real-time phasor
measurements from SEL-451 Relays across your
power system. Record streaming synchrophasor
data from SEL-451 Relays for system-wide
disturbance recording. Control the power system
using local and remote synchrophasor data.
SEL-451-5 Protection, Automation,
and Bay Control System

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
2
➤High-impedance Fault Detection. The optional
high-impedance fault (HIF) detection element
operates for small current ground faults typically
caused by downed conductors on surfaces such as
earth, concrete or other poorly conductive
materials. HIF event data are made available in
standard COMTRADE format.
➤Ethernet Access. Access all relay functions with
the optional Ethernet card. Interconnect with
automation systems by using IEC 61850 Edition 2
or DNP3 protocol directly. Use file transfer
protocol (FTP) for high-speed data collection.
Connect to substation or corporate LANs to
transmit synchrophasors in the IEEE C37.118–
2005 format by using TCP or UDP Internet
protocols.
➤Parallel Redundancy Protocol (PRP). Provide
seamless recovery from any single Ethernet
network failure, in accordance with IEC 62439-3.
The Ethernet network and all traffic are fully
duplicated with both copies operating in parallel.
➤IEC 61850 Operating Modes. The relay supports
IEC 61850 standard operating modes such as Test,
Blocked, On, and Off.
➤IEEE 1588, Precision Time Protocol. The relay
shall support Precision Time Protocol version 2
(PTPv2). PTP provides high-accuracy timing over
an Ethernet network.
➤Digital Relay-to-Relay Communications.
Enhanced MIRRORED BITS®communications can
monitor internal element conditions between bays
within a station, or between stations, using SEL
fiber-optic transceivers. Send digital, analog, and
virtual terminal data over the same MIRRORED
BITS channel.
➤Monitoring. Schedule breaker maintenance when
accumulated breaker duty (independently
monitored for each pole of two circuit breakers)
indicates possible excess contact wear. Electrical
and mechanical operating times are recorded for
both the last operation and the average of
operations since function reset. Two independent
DC monitors provide notification of substation
battery voltage problems even if voltage is low
only during trip or close operations.
➤Breaker Failure. High-speed (less than one cycle)
open-pole detection logic reduces coordination
times for critical breaker failure applications.
Apply the SEL-451 to supply breaker failure
protection for one or two breakers. Logic for
breaker failure retrip and initiation of transfer
tripping is included.
➤Sequential Events Recorder (SER). Record the
last 1000 events, including setting changes, power-
ups, and selectable logic elements.
➤Dual CT Input. Apply with ring bus, breaker-and-
a-half, or other two-breaker schemes. Combine
currents within the relay from two sets of CTs for
protection functions, but keep them separately
available for monitoring and station integration
applications.
➤Comprehensive Metering. Improve feeder
loading by using built-in, high-accuracy metering
functions. Watt and VAR measurements optimize
feeder operation. Minimize equipment needs with
full metering capabilities including rms,
maximum/minimum, demand/peak, energy, and
instantaneous values.
➤High-Accuracy Time-Stamping. Time-tag binary
COMTRADE event reports with real-time
accuracy of better than 10 µs. View system state
information to an accuracy of better than 1/4 of an
electrical degree.
➤Oscillography and Event Reporting. Record
voltages, currents, and internal logic points at a
sampling rate as fast as 8 kHz. Off line phasor and
harmonic-analysis features allow investigation of
bay and system performance.
➤Reclosing. Incorporate programmable reclosing of
one or two breakers into an integrated substation
control system. Synchronism and voltage checks
from multiple sources provide complete bay
control.
➤Fault Locator. Efficiently dispatch line crews to
quickly isolate line problems and restore service
faster.
➤IEC 60255-Compliant Thermal Model. Use
the relay to provide a configurable thermal model
for the protection of a wide variety of devices.
➤Rules-Based Settings Editor. Communicate with
and set the relay by using an ASCII terminal, or
use QuickSet to configure the SEL-451 and
analyze fault records with relay element response.
➤Auxiliary Trip/Close Pushbuttons. These
optional pushbuttons are electrically isolated from
the rest of the relay. They function independently
from the relay and do not need relay power.
➤Low-Energy Analog (LEA) Inputs. Reduce costs
and save space with as many as six C37.92-compliant
LEA voltage inputs.
➤Time-Domain Link (TiDL®) Technology. The
relay supports remote data acquisition through use
of an SEL-2240 Axion®. The Axion provides
remote analog and digital data over an IEC 61158
EtherCAT®TiDL network. This technology
provides very low and deterministic latency over a
fiber point-to-point architecture. The SEL-451
relay can receive fiber links from as many as eight
Axion remote data acquisition nodes.

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
3
Figure 1 Functional Diagram
ANSI NUMBERS/ACRONYMS AND FUNCTIONS
25
27
50
50BF
51
52PB
59
67
79
81 (O, U)
ADDITIONAL FUNCTIONS
16 SEC
50G
85 RIO SEL MIRRORED BITS Communications
BRM
DFR
HBL
HIZ
HMI
LDE
LGC Expanded SELOGIC Control Equations
LOC
MET
PMU
SBM
SER
1Copper or Fiber-Optic * Optional Feature
TiDL
Undervoltage
1
Bus
3
Line
Bus
3
3
1
SEL-451
1
IRIG-B
25 27 50 51
50BF
52PB 59 7967 85
RIO
BRM DFR HBLHIZ HMI LGC
LOC MET PMU SBMSER
4
EIA-232
2
Ethernet*1
16 S
EC
81O
U
SIP
THM
SIP
THM
Software-Invertible Polarities
IEC 60255-Compliant Thermal Model
32 (O, U)
Synchronism Check
Over- and Underpower
Overcurrent
Dual Breaker Failure Overcurrent
Time-Overcurrent
Trip/Close Pushbuttons*
Overvoltage
Directional Overcurrent
Autoreclosing
Over- and Underfrequency
32O
U
Access Security (Serial, Ethernet)
Best Choice Ground
Breaker Wear Monitor
Event Reports
Harmonic Blocking
High-Impedance Fault Detection Arc Sense™ Technology (AST)*
Operator Interface
Load Encroachment
Fault Locator
High-Accuracy Metering
Synchrophasors
Station Battery Monitor
Sequential Events Recorder
Time-Domain Link Remote Data Acquisition

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
4
Product Overview
Protection Features
Software-Invertible Polarities
Save Commissioning Time and
Costs
The SEL-451 provides software-invertible CT and PT
polarities. You can invert individual phase CT and PT
inputs to account for field wiring or invert whole CT ter-
minals to change a relay zone of protection without hav-
ing to change field wiring.
All signal processing uses the software-inverted polari-
ties for CEV file generation, metering, and protection
logic. COMTRADE file generation is isolated from the
impacts of the inverted polarities, and records signals as
applied to the relay terminals.
Directional Elements Increase
Sensitivity and Security
The SEL-451 provides multiple directional elements to
optimize security and sensitivity. Use ground and nega-
tive-sequence directional overcurrent elements to detect
high-resistance faults when using communications-
assisted tripping schemes.
The SEL-451 includes a number of directional elements
for supervision of overcurrent elements. The negative-
sequence directional element uses the same patented
principle proven in our SEL-351 Relay. This directional
element can be applied in virtually any application,
regardless of the amount of negative-sequence voltage
available at the relay location.
Figure 2 Product Overview
PROTECTION AUTOMATION BAY CONTROL
• Synchrophasors
• Directional Overcurrent (67)
• Dual Circuit Breaker Failure (50 BF)
• Synchronism Check (25)
• Instantaneous Overcurrent (50)
• Time Overcurrent (51)
• Over/Undervoltage (27/59)
• Over/Underpower (32)
• Frequency (81)
• Reclosing (79)
• Expanded SEL
OGIC Control Equations
• Event Reports and Oscillography
• Sequential Events Recorder (SER)
• Dual Breaker Condition Monitor
• Station Battery Monitor
• Fault Locator
• Load-Encroachment Supervision
• TiDL Remote Data Acquisition
• Ethernet Communications Protocols
IEC 61850 Edition 2
DNP3 LAN/WAN
FTP
Telnet
PRP
PTP
C37.118 Synchrophasors
• Ethernet Media Options
10/100BASE-T Twisted Pair Network
100BASE-FX Fiber-Optic Network
• Serial Communications Protocols
SEL ASCII Commands
SEL M
IRRORED B ITS Communications
SEL Fast Messages
DNP3
IEEE C37.118 Synchrophasors V7.3
• Password Separation of Automation and
Protection
• Configurable Bay Screen Display
• Local Control—As many as Two Breakers
• Status Indication—As many as
Three Breakers
• Local Control and Status Indication—As
many as 20 Disconnect Switches
• Bay Screen Displays—As many as
24 Analog Quantities
• Configurable Labels for Bus, Breakers,
Disconnect Switches, and Bay
• Password-Protected Control Functions
• Local and Remote Modes
• Control Confirmation Request
• Operation Alarm for Breaker and
Disconnect Switch
• As many as 10 individual one-line
diagrams available to HMI
Bus
Bus
Line
50BF
67 50
51
7925
3
1
3
1
3
81
27
59
52
52
Wide Area Network
Router
Hub or Switch
Remote
Monitoring
and Control
Local
Control
and Status
PTP
SEL-2488 Satellite-Synchronized
Network Clock
93820
93830
BK2
BK1
SW1
SW2
SW3 SW4
SW5
P: 10.4 MW
I: 430 A
Q: 1.2 MVAR
F: 60.1 HZ
SEL-451
SEL-2488

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
5
Ground overcurrent elements are directionally controlled
by three directional elements working together:
➤Negative-sequence voltage-polarized directional
element
➤Zero-sequence voltage-polarized directional element
➤Zero-sequence current-polarized directional element
Our patented Best Choice Ground Directional Element
selects the best ground directional element for the system
conditions and simplifies directional element settings
(you can override this automatic setting feature for spe-
cial applications).
Communications-Assisted
Tripping Schemes
Use communications to improve tripping time for better
customer service. The SEL-451 is the ideal relay for use
in pilot-based tripping schemes. Enhanced MIRRORED
BITS communications with SEL fiber-optic transceivers
provide 3–6 ms relay-to-relay transmission time. Among
the schemes supported are the following:
➤Permissive Overreaching Transfer Tripping (POTT)
➤Directional Comparison Unblocking (DCUB)
➤Directional Comparison Blocking (DCB)
Use the SELOGIC control equation TRCOMM to pro-
gram specific elements, combinations of elements,
inputs, etc., to perform communications scheme tripping
and other scheme functions. The logic readily accommo-
dates the following conditions:
➤Current reversals
➤Breaker open at one terminal
➤Weak-infeed conditions at one terminal
➤Switch-onto-fault conditions
Overcurrent Elements
The SEL-451 includes four phase, four negative-
sequence, and four ground instantaneous overcurrent ele-
ments. The SEL-451 also includes six selectable operat-
ing quantity inverse-time overcurrent elements. You can
select the operating quantities from the following:
IA, IB, IC, MAX(IA, IB, IC), I1, 3I2, IG
where IA, IB, IC can be fundamental or rms quantities
from either circuit breaker or combined currents.
The time-overcurrent curves (listed in Table 1)have two
reset characteristic choices for each time-overcurrent
element. One choice resets the elements if current drops
below pickup for one cycle. The other choice emulates
the reset characteristic of an electromechanical induction
disc relay.
Breaker Failure Protection
Incorporated into the SEL-451 is a full function breaker
failure system. Current can be individually monitored in
two breakers. High-speed open-pole detection logic
allows you to set the pickup current below minimum load
for sensitivity without sacrificing high-speed dropout.
Even in cases with delayed current zero in the secondary
of the CT caused by trapped flux, high-speed detection
of circuit breaker opening is achieved. This feature is
essential if breaker failure is initiated on all circuit
breaker trips. A reset of less than one cycle reduces coor-
dination times, improving stability.
Thermal Overload Protection
The SEL-451 supports three independent thermal ele-
ments that conform to the IEC 60255-149 standard. Use
these elements to activate a control action or issue an
alarm or trip when your equipment overheats as a result
of adverse operating conditions.
The SEL-2600 RTD Module provides ambient tempera-
ture measurements for the thermal model.
Loss-of-Potential (LOP) Logic
Supervises Directional Elements
The SEL-451 includes logic to detect an LOP caused by
failures such as blown fuses, which can cause an incor-
rect operation in directional elements. Simple settings
configure the LOP logic to either block or force forward
ground and phase directional elements under these con-
ditions. The logic checks for a sudden change in positive-
sequence voltage without a corresponding change in pos-
itive- or zero-sequence current. Tests and field experi-
ence show that this principle is very secure and is faster
than the tripping elements.
High-Impedance Fault Detection
High-impedance faults are short-circuit faults with fault
currents smaller than what a traditional overcurrent pro-
tective relay can detect. The SEL-451 includes logic used
to detect HIF signatures without being affected by loads
Table 1 Time-Overcurrent Curves
U.S. IEC
Moderately Inverse Standard Inverse
Inverse Very Inverse
Very Inverse Extremely Inverse
Extremely Inverse Long-Time Inverse
Short-Time Inverse Short-Time Inverse

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
6
and other system operation conditions. A running aver-
age provides a stable prefault reference and adaptive tun-
ing learns and tunes out feeder ambient noise conditions.
Decision logic differentiates an HIF condition from other
system conditions such as switching operations and
noisy loads. As much as 40 minutes of high-impedance
fault activity is stored in high-resolution COMTRADE
format and a summary of HIF activity is available using
ASCII commands. View important high-impedance fault
data from available metering commands.
Six Independent Settings Groups
Increase Operation Flexibility
The relay stores six settings groups. Select the active
settings group by control input, command, or other pro-
grammable conditions. Use these settings groups to
cover a wide range of control contingencies. Selectable
settings groups make the SEL-451 ideal for applications
requiring frequent settings changes and for adapting the
bay to changing system conditions.
Selecting a group also selects logic settings. Program
group logic to adjust settings for different operating con-
ditions, such as station maintenance, seasonal operations,
emergency contingencies, loading, source changes, and
adjacent relay settings changes.
Combined Current for Protection
Flexibility
In traditional relays, when protecting a line fed from two
breakers, such as a breaker-and-a-half system or double-
breaker system, you needed to combine the CT inputs
before connecting these inputs to the relay. The SEL-451
can accept separate inputs from two separate CTs and
mathematically combine the currents. This allows col-
lecting separate current metering and breaker monitor
information for each breaker. Breaker monitoring func-
tions for two breakers are done within one relay. Individ-
ual breaker currents allow for breaker failure functions
on a per-breaker basis within the SEL-451. Breaker diag-
nostics are reported on a comparative basis allowing for
advanced, proactive troubleshooting.
Custom Control Capabilities
Customize control capabilities, adding stability and secu-
rity to your system.
➤Use expanded SELOGIC control equations to create
advanced stability enhancements such as VAR-
flow controlled time undervoltage load shedding.
➤Combine frequency elements with voltage
supervision for added security with
underfrequency load-shedding systems.
Control Inputs and Outputs
The standard SEL-451 includes five independent and two
common inputs, two Form A and three Form C standard
interrupting outputs, and three Form A high-current
interrupting outputs. The following additional I/O boards
are currently available.
➤Eight independent inputs, 13 standard Form A and
two standard Form C contact outputs.
➤Eight independent inputs, eight high-speed, high-
current interrupting Form A contact outputs.
➤Eight independent inputs, 13 high-current
interrupting Form A outputs and two standard
Form C contact outputs.
➤Twenty-four inputs, six high-speed and two
standard Form A contact outputs.
Assign the control inputs for protection and control func-
tions, monitoring logic, and general indication. Each
control output is programmable using SELOGIC control
equations. No additional I/O boards can be added to the
3U chassis; however, one board can be added to the 4U
chassis, and two additional I/O boards can be added to
the 5U chassis.
Figure 3 VAR-Flow Controlled Time Undervoltage Load
Shedding
Volt Drop pu
Trip Time
Time (s)
15
10
5
00 0.5 1

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
7
Multifunction Reclosing With
Flexible Applications
The SEL-451 includes three-pole trip and reclose func-
tions, for either one or two breakers (Figure 4). Synchro-
nism check is included for breaker control.
Synchronizing and polarizing voltage inputs are fully
programmable with Dead Line/Dead Bus closing logic as
well as zero-closing-angle logic to minimize system
stress upon reclosing. Program as many as four reclose
attempts. Select Leader and Follower breakers directly,
or use a SELOGIC control equation to determine reclos-
ing order based on system conditions.
Two-Breaker Control
The SEL-451 contains analog voltage inputs for multiple
sources and control inputs to indicate both breaker and
disconnect position, as well as the logic required to pro-
vide full control for two breakers. This includes separate
monitoring functions as well as separate elements for
tripping and closing the two breakers to allow for
leader/follower operation or other desired control
schemes. All analog values are monitored on a per-
breaker basis to allow station control access to complete
information for individual components of the system.
Backup Protection
Add reliability and dependability by providing indepen-
dent backup protection without increasing relay count.
Use each SEL-451 to provide primary directional over-
current protection with backup nondirectional overcur-
rent protection on the adjacent feeder. For additional
flexibility, use the available I/O or MIRRORED BITS to
switch protection upon loss of one relay.
Bay Control
The SEL-451 Bay Control provides dynamic bay one-
line diagrams on the front-panel screen with disconnect
and breaker control capabilities for numerous predefined
user-selectable bay types. Additional user-selectable bay
types are available via a QuickSet interface that can be
downloaded at selinc.com. The bay control is equipped
to control as many as 10 disconnects and two breakers,
depending on the one-line diagram selected. Certain one-
line diagrams provide status for as many as three break-
ers and ten disconnect switches. Operate disconnects and
breakers with ASCII commands, SELOGIC control equa-
tions, Fast Operate Messages, and from the one-line dia-
gram. The one-line diagram includes user-configurable
apparatus labels and as many as 24 user-definable Ana-
log Quantities.
One-Line Bay Diagrams
The SEL-451 offers a variety of preconfigured one-line
diagrams for common bus configurations. Once a one-
line diagram is selected, the user has the ability to cus-
tomize the names for all of the breakers, disconnect
switches, and buses. Most one-line diagrams contain
analog display points. These display points can be set to
any of the available analog quantities with labels, units,
and scaling. These values are updated real-time along
with the breakers and switch position to give instant sta-
tus and complete control of a bay. The diagrams below
demonstrate some of the preconfigured bay arrange-
ments available in the SEL-451.
Figure 4 Two-Breaker Reclosing With Synchronism Check
52-1
52-2
Line
Bus 2
Bus 1
79
25
Figure 5 Using Two Cross-Connected SEL-451-5 Relays
to Provide Primary and Backup Protection for Two
Feeders
SEL-451 SEL-451

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
8
The operator can see all valuable information on a bay
before making a critical control decision. Programmable
interlocks help prevent operators from incorrectly open-
ing or closing switches or breakers. The SEL-451 will
not only prevent the operator from making an incorrect
control decision, but can notify and/or alarm when an
incorrect operation is initiated.
Circuit Breaker Operations From
the Front Panel
Figure 6 through Figure 9 are examples of some of the
many selectable one-line diagrams in the SEL-451. The
one-line diagram is selectable from the Bay settings.
Additional settings for defining labels and analog quanti-
ties are also found in the Bay settings. One-line diagrams
are composed of the following:
➤Bay Names and Bay Labels (Bay Labels available
in one-line diagrams 14, 17, 18, and 23. All other
one-line diagrams use the Bay Name.)
➤Busbar and Busbar Labels
➤Breaker and Breaker Labels
➤Disconnect Switches and Disconnect Switch Labels
➤Analog Display Points
Figure 10 shows the Breaker Control Screens available
when the ENT pushbutton is pressed with the circuit
breaker highlighted as shown in Figure 10 (a). After
pressing the ENT pushbutton with the breaker highlighted
Figure 6 Breaker-and-a-Half
Figure 7 Ring Bus With Ground Switch
BAYNAME
BK2
BK1
SW1 SW2
BK3
BAYLAB2BAYLAB1
BUSNAM1
BUSNAM2
ESCNAVIG
BAYNAME
6 ANALOGS
I:99999.9 A
V:99999.9 KV
P:99999.9 MW
Q:99999.9 MV
F:99.9 HZ
BAYLAB1
SW2
SW3
BK1
BK2
SW1
BAYLAB2
ESCNAVIG
Figure 8 Double Bus/Double Breaker
Figure 9 Source Transfer Bus
BAYNAME
6 ANALOGS
I:99999.9 A
V:99999.9 KV
P:99999.9 MW
Q:99999.9 MV
F:99.9 HZ
BUSNAM1
SW2
SW3
BK1 BK2
SW1
BUSNAM2
ESCNAVIG
BAYNAME
BUSNAM1
BK1 BK2
BUSNAM2
BAYLAB1
I:99999.9 A
V:99999.9 KV
P:99999.9 MW
I:99999.9 A
V:99999.9 KV
P:99999.9 MW
ESCNAVIG

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
9
and the LOCAL Relay Word bit asserted, the Breaker
Control Screen in Figure 10 (b) is displayed. After enter-
ing the screen in Figure 10 (b), the relay performs the
circuit breaker operations as outlined in the SEL-451-5
User’s Guide. If the LOCAL Relay Word bit is not
asserted when the ENT pushbutton is pressed, the screen
in Figure 10 (c) is displayed for three seconds, then the
bay control displays again the screen in Figure 10 (a).
Rack-Type Breakers Mosaics
The SEL-451 supports the display of rack-type (also
referred to as truck-type) circuit breakers. The rack-type
breakers have three positions: racked out, test, and
racked in. When in the test or racked-in positions, the
breaker can be displayed as open or closed. When racked
out, there is no breaker open/close display. The rack-type
breakers are a display-only functionality and do not
impact any circuit breaker control capabilities.
Status-Only Disconnects
The SEL-451 has the ability to designate a disconnect as
having control functionality or being status-only. When a
disconnect is designated as having control functionality,
the disconnect can be selected and controlled from the
relay front-panel HMI. When a disconnect is designated
as status-only, the disconnect is displayed in the one-line
diagram of the relay front-panel HMI, but it is not select-
able when navigating the front-panel HMI. Three-posi-
tion disconnects are also supported with control/display
functionality on a per position basis.
Rules-Based Settings Editor
QuickSet develops settings on- or offline. The system
automatically checks interrelated settings and highlights
out-of-range settings. Settings are transferred by using a
PC communications link with the SEL-451. The Quick-
Set interface supports Server 2008, Windows®7 and
Windows 8 operating systems, and can be used to open
COMTRADE files from SEL and other products. Con-
vert binary COMTRADE files to ASCII format for por-
tability and ease of use. View real-time phasors and
harmonic values.
Figure 10 Screens for Circuit Breaker Selection
Bus Labels
BAYNAME
BAYNAME
OPEN BREAKER
CLOSE BREAKER
OPEN
Bkrnam
PRESS TO ACTIVATE
Bay not in
LOCAL Control!
Cannot issue
controls.
Press Enter with breaker
highlighted
Breaker
Highlighted
(a) Bay Screen
(c) LOCAL Bit Not Asserted
(b) Breaker Control Screen
After three seconds,
re-display the previous screen
BUS 2
Dis 4
Bkr 1
Dis 3
Dis 1 Dis 2
BUS 1
BUS T
Bay Name
Disconnect
Switch Label
Disconnect
Switch Label
Disconnect
Switch Label
Analog
Quantities
Display
Breaker
Label
6 ANALOGS
I:99999.9 A
V:99999.9 KV
P:99999.9 MW
Q:99999.9 MV
F:60.000 HZ
ESCNAVIG
ESC
NAVIG

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
10
QuickSet Bay Control Settings Interface
There are two ways to enter Bay Control settings by
using the QuickSet settings interface. The standard style
settings are displayed in traditional form under the Bay
Control form. QuickSet also provides an interactive bay
control setting entry method. The interactive method
works by clicking on the one-line diagram labels. This
action automatically displays all the settings for the
device selected. This method provides an easy way of
organizing and verifying all settings associated with the
device.
Figure 11 illustrates the interactive bay control setting
form in QuickSet. Click on an apparatus in the one-line
diagram, and a form with apparatus-specific settings is
displayed.
QuickSet Templates
Use the fully licensed version of QuickSet to create custom
views of settings, called Application Designs, to reduce
complexity, decrease the chance of errors, and increase
productivity.
➤Lock and hide unused settings.
➤Lock settings to match your standard for protection,
I/O assignment, communications, and SELOGIC
control equations.
➤Enforce settings limits narrower than the device
settings.
➤Define input variables based on the equipment
nameplate or manufacturer’s terminology or scaling
and calculate settings from these “friendlier” inputs.
➤Use settings comments to guide users and explain
design reasoning.
Front-Panel Display
The LCD shows event, metering, settings, and relay self-
test status information. The target LEDs display relay
target information as described in Figure 12 and
explained in Table 2.
Figure 11 Interactive Bay Control Setting Form

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
11
The LCD is controlled by the navigation pushbuttons
(Figure 14), automatic messages the relay generates, and pro-
grammable analog and digital display points. The rotating
display scrolls through the bay screen, alarm points, display
points, and metering screens. Each display remains for an
adjustable time (1–15 seconds) before the display continues
scrolling. Any message generated by the relay because of an
alarm condition takes precedence over the rotating display.
Close-up views of the front panel of the SEL-451 are
shown in Figure 12, Figure 13, and Figure 14. The front
panel includes a 128 x 128 pixel, 3" x 3" LCD screen;
LED target indicators; and pushbuttons with indicating
LEDs for local control functions. The asserted and deas-
serted colors for the LEDs are programmable. Configure
any of the direct-acting pushbuttons to navigate directly
to an HMI menu item, such as events, bay display, alarm
points, display points, or the SER.
Status and Trip Target LEDs
The SEL-451 includes programmable target LEDs, as
well as programmable direct-action control pushbut-
tons/LEDs on the front panel. These LEDs and pushbut-
tons are shown in Figure 12 and Figure 13. Default
Target LED assignments are explained in Table 2 .
The SEL-451 features a versatile front panel that you can
customize to fit your needs. Use SELOGIC control equa-
tions and slide-in configurable front-panel labels to
change the function and identification of target LEDs and
operator control pushbuttons and LEDs. The blank slide-in
label set is included with the SEL-451. Label sets can be
printed from a laser printer using templates supplied with the
relay or hand labeled on supplied blank labels.
Figure 12 Factory-Default Status and Trip Target LEDs
(8 Pushbutton, 16 Target Option)
Figure 13 Factory-Default Status and Trip Target LEDs
(12 Pushbutton, 24 Target Option)
Figure 14 Front-Panel Display and Pushbuttons
ENABLED
TRIP
INST
TIME
COMM
SOTF
NEG-SEQ
79 RESET
79 CYCLE
79 LOCKOUT
A FAULT
B FAULT
C FAULT
GROUND
LOP
VAY ON
VBY ON
VCY ON
03/15/01 GROUP 1
00:00:05.387
EVENT: BCG T
LOCATION: 48.47
FREQ: 60.00
SHOT: 3P=1
BK1 OPEN
BK2 CLOSED
EVENT SUMMARY 10002
Table 2 Description of Factory-Default Target LEDs
Ta r g e t L E D Function
ENABLED Relay powered properly and self-tests okay
TRIP Indication that a trip occurred
INST High-speed rip
TIME Time-delayed trip
COMM Communications-assisted trip
SOTF Switch-onto-fault trip
RECLOSER
79 RESET
79 CYCLE
79 LOCKOUT
Ready for reclose cycle
Control in cycle state
Control in lockout state
PHASE
A, B, C
GROUND
Phases involved in fault
Ground involved in fault
LOP Loss-of-potential condition
VOLTAGES
VAY ON, VBY
ON, VCY ON
VAZ ONa, VBZ
ONa, VCZ ONa
aOnly available in 24-LED models.
VY phase filtered instantaneous voltages
applied
VZ phase filtered instantaneous voltages
applied
BKR FAILaBreaker Failure trip
BKR MAINTaBreaker maintenance needed
EXT TRIPaExternal trip detected
51 TIMINGa51 element picked up and timing
IRIG LOCKEDaIRIG synchronization detected

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
12
Advanced Display Points
Create custom screens showing metering values, special
text messages, or a mix of analog and status information
with programmable display points. Figure 15 shows an
example of how display points can be used to show cir-
cuit breaker information and current metering. As many
as 96 display points can be created. All display points
occupy one, and only one, line on the display at all times.
The height of the line is programmable as either single or
double as shown in Figure 15. These screens become
part of the autoscrolling display when the front panel
times out.
Alarm Points
You can display messages on the SEL-451 front-panel
LCD that indicate alarm conditions in the power system.
The relay uses alarm points to place these messages on
the LCD.
Figure 16 shows a sample alarm points screen. The relay
is capable of displaying as many as 66 alarm points. The
relay automatically displays new alarm points while in
manual-scrolling mode and in autoscrolling mode. The
alarm point messages are assigned using SER Points set-
tings. The asterisk next to the alarm point indicates an
active alarm. The inactive alarms can be acknowledged
and cleared using the front-panel navigation buttons.
Auxiliary Trip/Close Pushbuttons and
Indicating LEDs
Optional auxiliary trip and close pushbuttons (see
Figure 17) and indicating LEDs allow breaker control
independent of the relay. The auxiliary trip/close push-
buttons are electrically separate from the relay, operating
even if the relay is powered down. Make the extra con-
nections at terminals 201 through 208. See Figure 28 for a
rear-panel view. Figure 18 shows one possible set of con-
nections.
The auxiliary trip/close pushbuttons incorporate an arc
suppression circuit for interrupting dc trip or close cur-
rent. To use these pushbuttons with ac trip or close cir-
cuits, disable the arc suppression for either pushbutton by
changing jumpers inside the SEL-451. The operating
voltage ranges of the breaker CLOSED and breaker OPEN
indicating LEDs are also jumper-selectable.
Figure 15 Sample Display Points Screen
Figure 16 Sample Alarm Points Screen
Circuit Breaker 1
--Closed--
DISPLAY POINTS
Circuit BK1 SF6 Gas
--Alarm--
Circuit Breaker 2
A PH= 119.6 A pri
SF6 ALARM
*Unauthorized Access
*Xfmr Fan Fail
*Xfmr Heat Overload
ALARM POINTS
Press to acknldge
Figure 17 Operator Controls (Auxiliary Trip/Close Model)
Figure 18 Optional Breaker Trip/Close Control Switches
and Indicating Lamps
CLOSE
(manual/local)
TRIP
(manual/local)
Remote Close/
Auto-Reclose
Remote Trip/
Protection Trips
BREAKER
OPEN
LED
BREAKER
CLOSED
LED
43
local
To Close
Circuit
43
local
52b
52a
52
TC
––
++

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
13
Monitoring and Metering
Complete Metering Capabilities
The SEL-451 provides extensive metering capabilities as
listed in Table 3.
Event Reporting and Sequential
Events Recorder (SER)
Event Reports and Sequential Events Recorder features
simplify post-fault analysis and help improve your
understanding of both simple and complex protective
scheme operations. These features also aid in testing and
troubleshooting bay settings and control schemes. Oscil-
lograms are available in binary COMTRADE and ASCII
COMTRADE formats.
Oscillography and Event Reporting
In response to a user-selected internal or external trigger,
the voltage, current, and element status information con-
tained in each event report confirms relay, scheme, and
system performance for every fault. Decide how much
detail is necessary when an event report is triggered:
8 kHz, 4 kHz, 2 kHz, or 1 kHz resolution analog data.
The relay stores from 24 seconds of data per fault at
1 kHz resolution to 3 seconds per fault at 8 kHz resolu-
tion. Reports are stored in nonvolatile memory. Settings
operational in the relay at the time of the event are
appended to each event report.
Event Summary
Each time the SEL-451 generates a standard event report,
it also generates a corresponding Event Summary. This is
a concise description of an event that includes bay/termi-
nal identification, event date and time, fault location,
phase voltages, fault type at time of trip, and trip and
close times of day.
With an appropriate setting, the relay will automatically
send an Event Summary in ASCII text to one or more
relay communications ports each time an event report is
triggered.
Sequential Events Recorder (SER)
Use this feature to gain a broad perspective of relay ele-
ment operation. Items that trigger an SER entry are
selectable and can include input/output change of state,
element pickup/dropout, recloser state changes, etc. The
relay SER stores the latest 1,000 entries.
Voltage Sag, Swell, Interruption
Records
The SEL-451 can perform automatic voltage disturbance
monitoring for three-phase systems. The voltage
sag/swell/interruption (VSSI) recorder uses the VSSI
Relay Word bits to determine when to start (trigger) and
when to stop recording. The VSSI recorder uses nonvola-
tile memory, so de-energizing the relay will not erase any
stored VSSI data.
The recorded data are available through the VSSI report,
which includes date, time, current, voltage, and voltage
sag/swell/interruption (VSSI) element status during volt-
age disturbances, as determined by programmable set-
tings VINT, VSAG, and VSWELL. When the relay is
recording a disturbance, entries are automatically added
to the VSSI report at one of four rates, depending on the
length of the disturbance:
➤Once per quarter cycle
➤Once per cycle
➤Once per 64 cycles
➤Once per day
High-Accuracy Time Keeping
Using a combination of IRIG-B and a global positioning
satellite, the SEL-451 can time-tag oscillography to
within 10 µs accuracy. This high accuracy can be com-
bined with the high sampling rate of the relay to synchro-
nize data from across the system with an accuracy of
better than 1/4 electrical degree. This allows examination
of the power system state at given times, including load
angles, system swings, and other system-wide events.
Triggering can be via external signal (contact or commu-
nications port), set time, or system event. Optimal cali-
bration of this feature requires a knowledge of primary
input component (VT and CT) phase delay and error.
A single IRIG-B time-code input synchronizes the
SEL-451 time to within 1 ms of the time-source input.
A convenient source for this time code is the SEL-2032
Communications Processor (via Serial Port 1 on the
SEL-451).
Precision Time Protocol (PTP)
Time Synchronization
In addition to IRIG-B, the relay can be time-synchro-
nized through the Ethernet network by using IEEE 1588
Precision Time Protocol, version 2 (PTPv2). When con-
nected directly to a grandmaster clock providing PTP at

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
14
1-second sync intervals, the relay can be synchronized to
an accuracy of ±100 ns. The relay is capable of receiving
as many as 32 sync messages per second.
SNTP Time Synchronization
Use simple network time protocol (SNTP) to cost-effec-
tively synchronize SEL-451 Relays equipped with Ether-
net communication to as little as ±1 ms with no time-
source delay. Use SNTP as a primary time source, or as a
backup to a higher accuracy IRIG-B time input to the
relay.
Substation Battery Monitor for DC
Quality Assurance
The SEL-451 measures and reports the substation battery
voltage for two battery systems. Two sets of programma-
ble threshold comparators and associated logic provide
alarm and control of two separate batteries and chargers.
The relay also provides dual ground detection. Monitor
DC system status alarms with an SEL Communications
Processor and trigger messages, telephone calls, or other
actions.
The measured dc voltage is reported in the METER dis-
play via serial port communications, on the LCD, and in
the Event Report. Use the event report data to see an
oscillographic display of the battery voltage. Monitor the
substation battery voltage drops during trip, close, and
other control operations.
Figure 19 Example PTP Network
SEL-487B SEL-487E
SEL-411L SEL-421 SEL-451
GPS
SEL-2488
SEL-2740M
Figure 20 SNTP Diagram
SEL-2401 SEL-3354
SEL-2725
SEL-487E
Table 3 Metering Capabilities (Sheet 1 of 2)
Capabilities Description
Instantaneous Quantities
Voltages
VA,B,C (Y), VA,B,C (Z), V3V0, V1, 3V2
0–300 V with phase quantities for each of the six voltage sources available as a separate
quantity.
Currents
IA,B,C (W), IA,B,C (X)
IAL, IBL, ICL, (combined currents)
IGL, I1L, 3I2L (combined currents)
Phase quantities for each of the two current sources available as a separate quantity or
combined as line quantities.
Power/Energy Metering Quantities
MW, MWh, MVAR, MVA, PF,
single-phase and three-phase
Available for each input set and as combined quantities for the line.
Demand/Peak Demand Metering
IA,B,C, 3I2, 3I0Thermal or rolling interval demand and peak demand.
MW, MVAR, MVA, single-phase Thermal or rolling interval demand and peak demand.
MW, MVAR, MVA, three-phase Thermal or rolling interval demand and peak demand.

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
15
Breaker Monitor Feature Allows
for Wear-Based Breaker
Maintenance Scheduling
Circuit breakers experience mechanical and electrical
wear at each operation. Effective scheduling of breaker
maintenance takes into account the manufacturer’s pub-
lished data of contact wear versus interruption levels and
operation count. The SEL-451 dual breaker monitor fea-
ture compares the breaker manufacturer’s published data
to the integrated actual interrupted current and number of
operations.
➤Every time the breaker trips, the relay integrates
interrupted current. When the result of this
integration exceeds the threshold set by the breaker
wear curve (Figure 21), the bay can alarm via an
output contact or the optional front-panel display.
With this information, you can schedule breaker
maintenance in a timely, economical fashion.
➤The relay monitors last and average mechanical
and electrical interruption time. You can easily
determine if operating time is increasing beyond
reasonable tolerance to schedule proactive breaker
maintenance. You can activate an alarm point if
operation time goes beyond a preset value.
➤Breaker motor run time and breaker inactivity are
also monitored.
Automation
Time-Domain Link (TiDL) Technology
The SEL-451 supports remote data acquisition through
use of an SEL Axion with a technology known as TiDL.
The Axion provides remote analog and digital data over
an IEC 61158 EtherCAT TiDL network. This technology
provides very low and deterministic 1.5 ms latency over
a point-to-point architecture. The SEL-451 can receive as
many as eight fiber links from as many as eight Axion
remote data acquisition nodes.
The relay supports a number of fixed topologies. The
relay maps the voltage and current inputs from the Axion
to existing analog quantities in the SEL-451 based on the
connected topology. This limits the number of settings
and makes converting an existing system to TiDL easy.
Figure 22 show sample TiDL topologies. The SEL-451-5
Instruction Manual shows all supported topologies.
Synchrophasors
Voltages (Primary Magnitude, Angle)
VA,B,C (Y), V
A,B,C (Z)
Primary phase quantities (kV) for each of the six voltage sources available.
Currents (Primary Magnitude, Angle)
IA,B,C (W), IA,B,C (X)
Primary phase quantities (A) for each of the six current sources available.
Frequency
FREQ
dF/dT
Frequency (Hz) as measured by frequency source potential inputs.
Rate-of-change of frequency (Hz/s).
Table 3 Metering Capabilities (Sheet 2 of 2)
Capabilities Description
Figure 21 Breaker Contact Wear Curve and Settings
kA Interrupted
(Set Point 1)
(Set Point 2)
(Set Point 3)
Breaker Manufacturer's
Maintenance Curve
Close to Open Operations

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
16
Flexible Control Logic and
Integration Features
The SEL-451 control logic can be used to perform the
following:
➤Replace traditional panel control switches
➤Eliminate remote terminal unit (RTU)-to-bay wiring
➤Replace traditional latching relays
➤Replace traditional indicating panel lights
Eliminate traditional panel control switches with 32 local
control points. Set, clear, or pulse local control points with
the front-panel pushbuttons and display. Program the local
control points to implement your control scheme via
SELOGIC control equations. Use the local control points for
such functions as trip testing, enabling/disabling reclosing,
and tripping/closing circuit breakers.
Eliminate RTU-to-bay wiring with 32 remote control
points. Set, clear, or pulse remote control points via serial
port commands. Incorporate the remote control points
into your control scheme via SELOGIC control equations.
Use remote control points for SCADA-type control oper-
ations (e.g., trip, close, settings group selection).
Replace traditional latching relays for such functions as
“remote control enable” with 32 latching control points.
Program latch set and latch reset conditions with
SELOGIC control equations. Set or reset the latch control
points via control inputs, remote control points, local
control points, or any programmable logic condition. The
latch control points retain states when the relay loses power.
Replace traditional indicating panel lights and switches
with as many as 24 latching target LEDs and as many as
12 programmable pushbuttons with LEDs. Define cus-
tom messages (i.e., BREAKER OPEN, BREAKER CLOSED,
RECLOSER ENABLED) to report power system or relay con-
ditions on the large format LCD. Control which mes-
sages are displayed via SELOGIC control equations by
driving the LCD display via any logic point in the relay.
Open Communications Protocols
The SEL-451 does not require special communications
software. ASCII terminals, printing terminals, or a com-
puter supplied with terminal emulation and a serial com-
munications port are all that is required. Table 4 lists a
brief description of the terminal protocols.
Figure 22 Sample SEL-451 Topology
Port
6A
6B
6C
6D
6E
6F
Analogs
IAW, IBW, ICW
IAX, IBX, ICX
(optional)
VAY, VBY, VCY
VAZ (optional)
VBZ (optional)
VCZ (optional)
IAW, IBW, ICW
Feeder 1
IAW, IBW, ICW
Feeder 2
VAY,
VBY,
VCY
VAY,
VBY,
VCY
VAZ
(sync.
check)
SEL Axion
SEL Axion SEL Axion
SEL Axion
SEL Axion
SEL RelaySEL Relay
Control House
Substation Yard

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
17
SELOGIC Control Equations With
Expanded Capabilities and Aliases
Expanded SELOGIC 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 SELOGIC control equations consists of
combining relay elements, inputs, and outputs with
SELOGIC control equation operators (Table 5). Any ele-
ment in the Relay Word can be used in these equations.
For complex or unique applications, these expanded
SELOGIC 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
SELOGIC 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 SELOGIC control equations with expanded
capabilities.
➤Emulate a motor-driven reclose timer, including
stall, reset, and drive-to-lockout conditions (refer
to Figure 23).
➤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.
Ta b l e 5 S E L 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)

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
18
➤Restrict breaker tripping in excessive duty
situations without additional relays.
➤Construct a compensated overvoltage element for
open line overvoltage protection.
➤Hold momentary change-of-state conditions for
SCADA polling.
➤Provide a combination of frequency or rate-of-
change-of-frequency functions.
Relay-to-Relay Digital
Communications (MIRRORED BITS)
The SEL patented MIRRORED BITS technology provides
bidirectional relay-to-relay digital communication
(Figure 24). In the SEL-451, MIRRORED BITS can oper-
ate simultaneously on any two serial ports for three-ter-
minal power system operation.
This bidirectional digital communication creates addi-
tional outputs (transmitted MIRRORED BITS) and
additional inputs (received MIRRORED BITS) for each
serial port operating in the MIRRORED BITS communica-
tions mode. Communicated information can included
digital, analog, and virtual terminal data. Virtual terminal
allows operator access to remote bays through the local
bay. These MIRRORED BITS can be used to transfer informa-
tion between line terminals to enhance coordination and
achieve faster tripping. MIRRORED BITS also help reduce total
pilot scheme operating time by eliminating the need to close
output contacts and debounce contact outputs. Use the dual-
port MIRRORED BITS communications capabilities for high-
speed communications-assisted schemes applied to three-ter-
minal transmission lines.
Communication
The SEL-451 offers the following serial communication
features.
➤Four independent EIA-232 serial ports.
➤Full access to event history, relay status, and meter
information.
➤Settings and group switching have three levels of
password protection.
➤DNP3 Level 2 Outstation.
➤Patented SEL Fast Message Interleaving of ASCII
and binary data for SCADA communications,
including access to SER, relay element targets,
event data and more.
➤Communication of synchronized phasor
measurement data using either SEL Fast
Messaging for Synchrophasors or IEEE C37.118–
2005 Standard for Synchrophasors for Power
Systems.
Figure 23 Motor-Driven Reclose Timer
3rd Reclose
(Synchronism Check)
2nd Reclose
(Hot Bus/Dead Line)
1st Reclose
(Hot Line/Dead Bus)
Reset
Lockout
Figure 24 Integral Communication Provides Secure Protection, Monitoring, and Control, as Well as Terminal Access to
Both Relays Through One Connection
Fiber-Optic Cable
TX
RX
TX
RX
SEL-2815 SEL-2815
Other
Bays
Other
Bays
Bus 1 Bus 2
1 2
Digital, Analog, and Virtual Terminal Data
SEL-451 SEL-451

Schweitzer Engineering Laboratories, Inc. SEL-451 Data Sheet
19
Network Connection and Integration
Connect the SEL-451 to Local Area Networks (LANs)
by using the optional Ethernet card. The integrated
Ethernet card supports both copper and/or fiber connec-
tions with failover protection.
Ethernet Card
The optional Ethernet card mounts directly in the
SEL-451. Use popular Telnet applications for easy termi-
nal communications with SEL relays and other devices.
Transfer data at high speeds (10 Mbps or 100 Mbps) for
fast HMI updates and file uploads. The Ethernet card
communicates using File Transfer Protocol (FTP) appli-
cations for easy and fast file transfers.
Provide operations with situational awareness of the
power system by using IEEE C37.118-2005 Standard for
Synchrophasors for Power Systems. Communicate with
SCADA and other substation intelligent electronic
devices (IEDs) by using DNP3 or IEC 61850 logical
nodes and GOOSE messaging.
Choose Ethernet connection media options for primary
and standby connections:
➤10/100BASE-T Twisted Pair Network
➤100BASE FX Fiber-Optic Network
Telnet and FTP
Order the SEL-451 with Ethernet communication and
use the built-in Telnet and File Transfer Protocol (FTP)
that come standard with Ethernet to enhance relay com-
munications sessions. Use Telnet to access relay settings,
and metering and event reports remotely using the ASCII
interface. Transfer settings files to and from the relay via the
high-speed Ethernet port through use of FTP.
IEEE C37.118 Synchrophasors
The latest IEEE Synchrophasor Protocol provides a stan-
dard method for communicating synchronized phasor
measurement data over Ethernet or serial media. The
integrated Ethernet card in the SEL-451 provides two
independent connections by using either TCP/IP,
UDP/IP, or a combination thereof. Each connection sup-
ports unicast or multicast options for serving data to one or
multiple clients simultaneously. Each data stream can support
data streams at as fast as 60 frames per second.
DNP3 LAN/WAN
The DNP3 LAN/WAN option provides the SEL-451
with DNP3 Level 2 Outstation functionality over Ether-
net. Custom DNP3 data maps can be configured for use
with specific DNP3 masters. The PTP power profile is
also supported over PRP.
Precision Time Protocol (PTP)
An Ethernet card option with Ports 5A and 5B populated
provides the ability to accept IEEE 1588 Precision Time
Protocol, version 2 (PTPv2) for data time synchroniza-
tion. Optional PTP support includes both the Default and
Power System (C37.238-2011) PTP Profiles.
Figure 25 Network Connection and Integration
SEL-451-5 SEL-3355SEL-451-5
Protection, Automation, & Control
STANDBY LAN
PRIMARY LAN
Modem
Remote
Access
PTP
PTP
Bus Protection/System Control
Ethernet
Card
Ethernet
Card
Ethernet
Card
Remote
Monitoring
Remote
Control
Local
Control
Communications Processor
SEL-2488 Satellite-Synchronized
Network Clock
Telnet
DNP3
LAN/WAN
PTP
IEC 61850
DNP3 LAN/WAN
PRP
PTP
IEC 61850
DNP3 LAN/WAN
IEEE C37.118
PRP
PTP
SEL-2488

SEL-451 Data Sheet Schweitzer Engineering Laboratories, Inc.
20
Parallel Redundancy Protocol (PRP)
This protocol is used to provide seamless recovery from
any single Ethernet network failure, in accordance with
IEC 62439-3. The Ethernet network and all traffic are
fully duplicated with both copies operating in parallel.
HTTP Web Server
When equipped with Ethernet communications, the relay
can serve read-only web pages displaying certain set-
tings, metering, and status reports. As many as four users
can access the embedded HTTP server simultaneously.
IEC 61850 Edition 2 Ethernet
Communications
IEC 61850 Edition 2 Ethernet-based communications
provide interoperability among IEDs within the substa-
tion. Logical nodes using IEC 61850 allow standardized
interconnection of IEDs from different manufacturers for
monitoring and control of the substation. Reduce wiring
among various manufacturers’ devices and simplify
operating logic with IEC 61850. Eliminate system RTUs
by streaming monitoring and control information from
IEDs directly to remote SCADA client devices.
The SEL-451 can be ordered with embedded IEC 61850
Edition 2 protocol operating on 100 Mbps Ethernet. Use
the IEC 61850 Edition 2 Ethernet protocol for relay
monitoring and control functions, including the follow-
ing:
➤As many as 128 incoming GOOSE messages. The
incoming GOOSE messages can be used to control
as many as 256 control bits and 256 analog
quantities in the relay with <3 ms latency from
device to device. These messages provide binary
control inputs to the relay for high-speed control
functions and monitoring.
➤As many as eight outgoing GOOSE messages.
Outgoing GOOSE messages can be configured for
Boolean and/or analog data. Boolean data are
provided with <3 ms latency from device to
device. Use outgoing GOOSE messages for high-
speed control and monitoring of external breakers,
switches, and other devices.
➤IEC 61850 Edition 2 Data Server. The SEL-451 is
equipped with embedded IEC 61850 Ethernet
protocol that provides data according to pre-
defined logical node objects. As many as seven
simultaneous client associations are supported by
each relay. Relevant Relay Word bits are available
within the logical node data, so status of relay
elements, inputs, outputs or SELOGIC control
equations can be monitored using the IEC 61850
data server provided in the relay.
➤The SEL-451 supports IEC 61850 standard
operating modes such as Test, Blocked, On, and
Off.
Figure 26 Typical Web Server Default Menu Screen