Schweitzer Engineering Laboratories SEL-787-2 User manual

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
As Many as Four-Terminal Differential and REF Protection
New Features
➤Disconnect control from the Bay Screens application.
➤Three-position disconnects for increased safety.
➤A built-in web server that simplifies access to relay data and supports firmware upgrade.
➤Faster firmware downloads via the Ethernet port.
➤IEEE 1588-2008 firmware-based Precision Time Protocol (PTP) provides ease of integration.
➤EtherNet/IP provides ease of integration for industrial automation applications.
➤IEC 61850 Test Mode support with standard operating modes On, Blocked, Test, Test/Blocked, and Off for easy
commissioning.
SEL-787-2, -3, -4 Transformer
Protection Relays

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
2
Major Features and Benefits
The SEL-787 Transformer Protection Relay provides unsurpassed protection, integration, and control features in a
flexible, compact, and cost-effective package. The SEL-787 offers an extensive variety of protection features, depending
on the model and options selected. In this document, SEL-787 refers to all the models in Table 1. For protection func-
tions specific to a given MOT, the relay is referred to as SEL-787-4X, SEL-787-3E, SEL-787-3S, SEL-787-2X,
SEL-787-21, or SEL-787-2E explicitly, where needed. Table 2 shows the protection features available across models.
Table 1 Current (ACI) and Voltage (AVI) Card Selection for SEL-787 Models
Model Description/Application Slot Z Card
(MOT Digits) Slot Z Inputs Slot E Card (MOT Digits) Slot E Inputs
787-2X 2 Winding/Terminal Current Differential 6ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
787-21 2 Winding/Terminal Current Differential
1 Neutral Current Input
6ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
1ACI
(A6, A7)
IN
787-2E 2 Winding/Terminal Current Differential
1 Neutral Current Input
3 Voltage Inputs (Phase)
6ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
1ACI/3AVI
(78, 79)
IN, VA, VB, VC
787-3E 3 Winding/Terminal Current Differential
1 Neutral Current Input
3 Voltage Inputs (Phase)
6ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
4ACI/3AVI
(72, 73, 76, 77)
IAW3, IBW3,
ICW3, IN, VA,
VB, VC
787-3S 3 Winding/Terminal Current Differential
3 Voltage Inputs (Phase)
1 Voltage Input (Vsync or Vbat)
6ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
3ACI/4AVI
(71, 75)
IAW3, IBW3,
ICW3, VS/VBAT,
VA, VB, VC
787-4X 4 Winding/Terminal Current Differential 6 ACI
(81, 82, 85)
IAW1, IBW1, ICW1,
IAW2, IBW2, ICW2
6ACI
(A1, A2, A5)
IAW3, IBW3,
ICW3, IAW4,
IBW4, ICW4
Table 2 SEL-787 Protection Elements (Sheet 1 of 2)
Protection Elements
2 Windings
2 Windings With
IN Channel
2 Windings With
IN Channel and
3-Phase Voltages
3 Windings With
IN Channel and
3-Phase Voltages
3 Windings With
VS/VBAT Channel and
3-Phase Voltages
4 Windings
SEL-787-2X SEL-787-21 SEL-787-2E SEL-787-3E SEL-787-3S SEL-787-4X
87PhaseDifferential XXXXXX
REF Restricted Earth Fault (REF) XaXaXaXaXa
50PPhaseOvercurrent XXXXXX
50Q Neg.-Seq. Overcurrent XXXXXX
50GGroundOvercurrent XXXXXX
50N Neutral Overcurrent XXX
51PPhaseTime-Overcurrent XXXXXX
51Q Neg.-Seq. Time-Overcurrent XXXXXX
51GGroundTime-OvercurrentXXXXXX
51PC Combined Winding Phase
Time-Overcurrent XXX
51GC Combined Winding Ground
Time-Overcurrent XXX

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
3
➤Standard Protection Features. Use standard dual-slope differential protection with harmonic blocking and restraint
for as many as four windings and as many as three independent REF elements for sensitive ground-fault detection in
grounded wye-transformers. Refer to Table 3 for the available REF elements. The relay also includes phase,
negative-sequence, residual ground, and neutral-ground overcurrent elements for backup protection. Breaker failure
protection for as many as four three-pole breakers is standard.
➤Additional Protection Features. Take advantage of the SEL-787-3E/3S/2E models volts/hertz protection with
frequency tracking from 15 to 70 Hz for generator step-up and variable frequency applications. Use over- and
underfrequency and over- and undervoltage elements to implement load shedding and other control schemes on the
relay.
51N Neutral Time-Overcurrent XXX
27P Phase Undervoltage X X X
27PP Phase-to-Phase Undervoltage XXX
27S VS Channel Undervoltage X
27I Inverse-Time Undervoltage XXX
59P Phase Overvoltage X X X
59PP Phase-to-Phase Overvoltage XXX
59Q Neg.-Seq. Overvoltage X X X
59G Ground Overvoltage XXX
59S VS Channel Overvoltage X
59I Inverse-Time Overvoltage XXX
24Volts/Hz XXX
25 Synchronism Check X
32 Directional Power X X X
49RTD Resistance Temperature Detector
(RTDs)
XXXXXX
60LOP Loss of Potential (LOP) X X X
81 Over- and Underfrequency XXX
BFBreakerFailure XXXXXX
aRefer to Table 3 for the available REF elements.
Table 3 Available Differential and REF Elements
Elements SEL-787-2X SEL-787-21 SEL-787-2E SEL-787-3E SEL-787-3S SEL-787-4X
Differential Protection Windings
(Standard)
222334
REF Elements (Standard) 0 1 1 1 0 0
Differential Protection Windings
(Winding 3 Configured for REF)
223
REF Elements
(Winding 3 Configured for REF)
222
Table 2 SEL-787 Protection Elements (Sheet 2 of 2)
Protection Elements
2 Windings
2 Windings With
IN Channel
2 Windings With
IN Channel and
3-Phase Voltages
3 Windings With
IN Channel and
3-Phase Voltages
3 Windings With
VS/VBAT Channel and
3-Phase Voltages
4 Windings
SEL-787-2X SEL-787-21 SEL-787-2E SEL-787-3E SEL-787-3S SEL-787-4X

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
4
➤Synchronism Check/Station DC Battery Monitor. Program the VS/VBAT voltage channel in the SEL-787-3S
model to perform a synchronism check across a circuit breaker or to monitor dc voltage levels of the substation
battery.
➤Transformer Monitoring. Measure accumulated through-fault levels with the transformer through-fault monitor.
Additionally, use the optional 4–20 mA or RTD thermal inputs to monitor ambient, load tap changer (LTC) tank, and
transformer oil temperatures.
➤Operator Controls. Take advantage of eight programmable front-panel pushbuttons, each with two programmable
tricolor LEDs, for various uses, such as easy trip and close control and status indication for all the breakers. Use the
operator control interface pushbuttons to easily implement local and remote operator control schemes using 32 local
and 32 remote control bits. Use SELOGIC®control equations and slide-in, configurable front-panel labels to change
the function and identification of target LEDs and operator control pushbuttons and LEDs.
➤Integrated Web Server. Log in to the built-in web server to view metering and monitoring data and to download
events. Use the web server to view relay settings and to perform relay firmware upgrades.
➤Relay and Logic Settings Software. Reduce engineering costs by using ACSELERATOR QuickSet®SEL-5030
Software for relay settings and logic programming and to simplify development of SELOGIC control equations.
Verify proper CT polarity and phasing through use of the built-in phasor display.
➤Metering and Reporting. Use built-in metering functions to eliminate separately mounted metering devices.
Analyze Sequential Events Recorder (SER) reports and oscillographic event reports for rapid commissioning,
testing, and post-fault diagnostics. Unsolicited SER protocol allows station-wide collection of binary SER messages.
➤Front-Panel HMI. Navigate the relay HMI using a 2 x 16-character LCD or optional 5-inch, color, 800 x 480-pixel
touchscreen display.
➤Additional Standard Features. Further enhance your power system protection by taking advantage of several other
SEL-787 standard features in communication, monitoring, and support. Modbus RTU, Event Messenger support,
MIRRORED BITS®communications, as well as load profile and breaker wear monitoring all come standard with the
SEL-787. The relay also supports 12 additional external RTDs (SEL-2600 RTD Module), IRIG-B input, advanced
SELOGIC control equations, 128 remote analogs, IEEE C.37.118-2005-compliant synchrophasor protocol,
configurable labels, and an SEL-2812 compatible ST fiber-optic serial port.
➤Optional Features. Communicate with a number of additional optional communications protocols and ports,
digital/analog I/O, and RTDs. Optional communications protocols include IEC 61850 Edition 2, Modbus TCP/IP,
Simple Network Time Protocol (SNTP), IEEE 1588-2008 firmware-based PTP, PRP for dual Ethernet models,
DNP3 LAN/WAN, DNP3 serial, and IEC 60870-5-103. Elective communications ports include EIA-232 or EIA-485
and single or dual, copper or fiber-optic Ethernet ports. Several digital/analog I/O options are available. These
include 4 AI/4 AO, 4 DI/4 DO, 8 DI, 8 DO, 3 DI/4 DO/1 AO, 4 DI/3 DO, and 14 DI. An optional 10 internal RTD
card is also available for the SEL-787 relay. Conformal coating for chemically harsh and/or high moisture
environments is also available as an option.
➤Language Support. Choose English or Spanish for your serial ports, including the front-panel serial port. The
standard relay front-panel overlay is in English; a Spanish overlay is available as an ordering option.

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
5
Functional Overview
Figure 1 SEL-787-3E Functional Diagram
3
3
3
1
Temperature Alarm
and Trip
SEL-787-3E Transformer Protection Relay
52
52
Overcurrent
• Phase
• Ground
• Neg-Seq
• Breaker Failure
Time-Overcurrent
• Phase
• Ground
• Neq-Seq
Combined
Time-
Overcurrent
• Phase
• Ground
Overcurrent
• Phase
• Ground
• Neg-Seq
• Breaker Failure
Time-Overcurrent
• Phase
• Ground
• Neg-Seq
• Sequential Events Recorder
• Event Reports
• Web Server
• SEL, Ethernet*, Modbus RTU, Modbus TCP/IP*,
DNP3 serial*, DNP3 LAN/WAN*, FTP*, Telnet*, SNTP*,
IEEE 1588-2008 firmware-based PTP*, IEC 61850 Edition 2*,
IEC 60870-5-103*, EtherNet/IP*, PRP*, Event Messenger,
DeviceNet* Communications
• Synchrophasor Data and IEEE C37.118-2005 Compliant
Protocol
• Two Inputs and Three Outputs Standard
• I/O Expansion*--Additional Contact Inputs/Outputs, Analog
Inputs/Outputs, and RTD Inputs
• Single or Dual Ethernet Copper or Fiber-Optic
Communications Port*
Σ5151 P
G
8787
Overcurrent
• Phase
• Ground
• Neg-Seq
• Breaker Failure
Time-Overcurrent
• Phase
• Ground
• Neg-Seq
Overcurrent Time-Overcurrent
3232
2424 8181 O
U
Volts/Hertz Frequency
• Over
• Under
LOPLOP
27P27P 5959
Restricted
Earth Fault
Directional
Power
Loss of Potential
Undervoltage Overvoltage
• Phase
• Ground
• Neg-Seq
• Breaker Failure
Current
Differential
3
52
• Battery-Backed Clock, IRIG-B Time Synchronization
• Instantaneous, Differential, Harmonic, and RMS
Metering
• Programmable Pushbuttons and LED Indicators
• Through-Fault Monitoring
• Transformer Thermal Monitoring
• Circuit Breaker Contact Wear Monitor
• Advanced SELOGIC Control Equations
• 32 Programmable Display Messages
• MIRRORED BITS Communications
• Front-Panel Programmable Tricolor LED Targets
• Front-Panel HMI With 2 x 16-Character LCD
• 5-Inch, Color, 800 x 480-Pixel Touchscreen Display*
*Optional Functions
Internal or External
RTD Input
27I27I 59I59I
Inverse-Time
Overvoltage
Inverse-Time
Undervoltage
REFREF

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
6
Figure 2 SEL-787-3S Functional Diagram
3
3
3
1
Temperature Alarm
and Trip
SEL-787-3S Transformer Protection Relay
52
52
Overcurrent Time-Overcurrent
Combined
Time-
Overcurrent
Overcurrent Time-Overcurrent
• Sequential Events Recorder
• Event Reports
• Web Server
• SEL, Ethernet*, Modbus RTU, Modbus TCP/IP*,
DNP3 serial*, DNP3 LAN/WAN*, FTP*, Telnet*, SNTP*,
IEEE 1588-2008 firmware-based PTP*, IEC 61850 Edition 2*,
IEC 60870-5-103*, EtherNet/IP*, PRP*, Event Messenger,
DeviceNet* Communications
• Synchrophasor Data and IEEE C37.118-2005 Compliant
Protocol
• Two Inputs and Three Outputs Standard
• I/O Expansion*--Additional Contact Inputs/Outputs,
Analog Inputs/Outputs, and RTD Inputs
• Single or Dual Ethernet Copper or Fiber-Optic
Communications Port*
Σ5151 P
G
8787
Overcurrent Time-Overcurrent
Undervoltage Overvoltage
3232
2424 8181 O
U
Volts/Hertz Frequency
LOPLOP
27P27P 5959
Synch Check
Directional
Power
Loss of Potential
Undervoltage Overvoltage
Current
Differential
3
52
• Battery-Backed Clock, IRIG-B Time Synchronization
• Instantaneous, Differential, Harmonic, and RMS
Metering
• Programmable Pushbuttons and LED Indicators
• Through-Fault Monitoring
• Transformer Thermal Monitoring
• Circuit Breaker Contact Wear Monitor
• Advanced SELOGIC Control Equations
• 32 Programmable Display Messages
• MIRRORED BITS Communications
• Front-Panel Programmable Tricolor LED Targets
• Front-Panel HMI With 2 x 16-Character LCD
• 5-Inch, Color, 800 x 480-Pixel Touchscreen Display*
*Optional Functions
Internal or External
RTD Input
2525
27S27S 59S59S
27I27I 59I59I
Inverse-Time
Undervoltage
Inverse-Time
Overvoltage

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
7
Figure 3 SEL-787-4X Functional Diagram
3
Temperature Alarm
and Trip
SEL-787-4X Transformer Protection Relay
52
52
Overcurrent Time-Overcurrent
Combined
Time-
Overcurrent
Overcurrent Time-Overcurrent
• Sequential Events Recorder
• Event Reports
• Web Server
• SEL, Ethernet*, Modbus RTU, Modbus TCP/IP*,
DNP3 serial*, DNP3 LAN/WAN*, FTP*, Telnet*, SNTP*,
IEEE 1588-2008 firmware-based PTP*, IEC 61850 Edition 2*,
IEC 60870-5-103*, EtherNet/IP*, PRP*, Event Messenger,
DeviceNet* Communications
• Synchrophasor Data and IEEE C37.118-2005 Compliant
Protocol
• Two Inputs and Three Outputs Standard
• I/O Expansion*--Additional Contact Inputs/Outputs, Analog
Inputs/Outputs, and RTD Inputs
• Single or Dual Ethernet Copper or Fiber-Optic
Communications Port*
Σ51
51
P
G
87
87
Current
Differential
3
• Battery-Backed Clock, IRIG-B Time Synchronization
• Instantaneous, Differential, Harmonic, and RMS
Metering
• Programmable Pushbuttons and LED Indicators
• Through-Fault Monitoring
• Transformer Thermal Monitoring
• Circuit Breaker Contact Wear Monitor
• Advanced SELOGIC Control Equations
• 32 Programmable Display Messages
• MIRRORED BITS Communications
• Front-Panel Programmable Tricolor LED Targets
• Front-Panel HMI With 2 x 16-Character LCD
• 5-Inch, Color, 800 x 480-Pixel Touchscreen Display*
*Optional Functions
Internal or External
RTD Input
3
52
52
Overcurrent Time-Overcurrent
Combined
Time-
Overcurrent
Overcurrent Time-Overcurrent
Σ51
51
P
G
3

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
8
Figure 4 SEL-787-2E/21/2X Functional Diagram
3
3
3
1
Temperature Alarm
and Trip
SEL-787-2E/21/2X Transformer Protection Relay
52
Overcurrent Time-Overcurrent
• Sequential Events Recorder
• Event Reports
• Web Server
• SEL, Ethernet*, Modbus RTU, Modbus TCP/IP*,
DNP3 serial*, DNP3 LAN/WAN*, FTP*, Telnet*, SNTP*,
IEEE 1588-2008 firmware-based PTP*, IEC 61850 Edition 2*,
IEC 60870-5-103*, EtherNet/IP*, PRP*, Event Messenger,
DeviceNet* Communications
• Synchrophasor Data and IEEE C37.118-2005 Compliant
Protocol
• Two Inputs and Three Outputs Standard
• I/O Expansion*--Additional Contact Inputs/Outputs, Analog
Inputs/Outputs, and RTD Inputs
• Single or Dual Ethernet Copper or Fiber-Optic
Communications Port*
8787
Overcurrent Time-Overcurrent
OvercurrentaTime-Overcurrenta
3232
2424 8181 O
U
Volts/HertzbFrequencyb
LOPLOP
27P27P 5959
Restricted
Earth Faulta
Directional
Powerb
Loss of Potentialb
UndervoltagebOvervoltageb
Current
Differential
52
• Battery-Backed Clock, IRIG-B Time Synchronization
• Instantaneous, Differential, Harmonic, and RMS
Metering
• Programmable Pushbuttons and LED Indicators
• Through-Fault Monitoring
• Transformer Thermal Monitoring
• Circuit Breaker Contact Wear Monitor
• Advanced SELOGIC Control Equations
• 32 Programmable Display Messages
• MIRRORED BITS Communications
• Front-Panel Programmable Tricolor LED Targets
• Front-Panel HMI With 2 x 16-Character LCD
• 5-Inch, Color, 800 x 480-Pixel Touchscreen Display*
*Optional Functions
Internal or External
RTD Input
27I27I 59I59I
Inverse-Time
Overvoltageb
Inverse-Time
Undervoltageb
aNeutral and REF elements are
available in the SEL-787-21/2E models
only
bVoltage and power elements are
available in the SEL-787-2E model only
REFREF

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
9
Protection Features
The SEL-787 relay offers a dual-slope differential char-
acteristic for transformer differential protection. The
SEL-787 includes a complete set of phase, negative-
sequence, and residual overcurrent elements for each ter-
minal (winding), as well as REF and neutral-overcurrent
elements for grounded wye transformers.
Use as many as 12 independent RTD-driven thermal
elements with trip and alarm levels to monitor ambient
and equipment temperatures throughout the substation.
For the optional volts/hertz element, you can add three-
phase voltage inputs that give the SEL-787 volts/hertz
protection with definite-time and time-delay
characteristics, along with directional power, over- and
underfrequency, and over- and undervoltage elements
with two independent pickup levels and time delays.
Transformer Differential
The SEL-787 has three restrained differential elements
(87R). These elements use operate and restraint quanti-
ties calculated from as many as four winding input cur-
rents. Set the differential elements with either single- or
dual-slope percentage differential characteristics.
Figure 5 illustrates a dual-slope setting. The percent-
slope characteristic helps prevent undesired relay opera-
tion because of a possible unbalance between CTs during
external faults. CT unbalance can result from TAP
changing in the power transformer and error difference
between the CTs on either side of a power transformer.
Figure 5 Dual-Slope Restrained Differential
Characteristic
With the SEL-787, you can choose harmonic blocking,
harmonic restraint, or both, to provide reliable
differential protection during transformer inrush
conditions. Even-numbered harmonics (second and
fourth) provide security during energization, while fifth-
harmonic blocking provides security for overexcitation
conditions. Set second-, fourth-, and fifth-harmonic
thresholds independently.
An additional alarm function for the fifth-harmonic
current employs a separate threshold and an adjustable
timer to warn of overexcitation. This may be useful for
transformer applications in or near generating stations. A
set of unrestrained differential current elements simply
compares the differential operating current quantity to a
setting value, typically about 10 times the TAP setting.
This pickup setting is only exceeded for internal faults.
The three independent unrestrained differential elements
(87U) provide rapid assertion without delay when
differential operate current levels exceed the 87U pickup
threshold that is set. Typical 87U pickup level settings
are between 8 and 10 per unit of the operate current.
Restricted Earth Fault Protection
Apply the REF protection feature to provide sensitive
detection of internal ground faults on grounded
wye-connected transformer windings and auto-
transformers. Refer to Ta b le 3 for the available REF ele-
ments across the models. Polarizing current is derived
from the residual current calculated for the protected
winding(s). A sensitive directional element determines
whether the fault is internal or external. Zero-sequence
current thresholds supervise tripping.
Overcurrent Protection
The SEL-787 offers instantaneous overcurrent and time-
overcurrent elements. All the elements can be controlled
individually by using the SELOGIC torque control equa-
tions associated with the element.
Instantaneous Overcurrent Elements
The following instantaneous overcurrent elements are
available in the SEL-787.
➤Four instantaneous phase overcurrent (50P) elements
per winding that operate on the maximum of the
phase currents. A peak detection algorithm is used to
enhance element sensitivity during high-fault current
conditions where severe CT saturation may occur.
➤Per-phase instantaneous overcurrent (50P) elements,
one element per phase, that operate on the corre-
sponding phase current of Winding 3 (only available
on models with Winding 3). A peak detection algo-
rithm is used to enhance element sensitivity during
high-fault current conditions where severe CT satura-
tion may occur.
➤Two instantaneous negative-sequence overcurrent
(50Q) elements per winding that operate on the calcu-
lated negative-sequence current.
➤Two residual instantaneous overcurrent (50G) ele-
ments per winding that operate on the calculated
residual (3I0) current.
Operating Region
Restraining Region
IRT
70%
25%
IOP
087P = 0.3
Slope 2
(SLP2)
IRS1 = 6
Slope 1
(SLP1)

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
10
➤Two neutral instantaneous overcurrent (50N) ele-
ments that operate on the neutral current associated
with the neutral channel (MOT dependent).
Time-Overcurrent Elements
The time-overcurrent elements support the IEC and U.S.
(IEEE) time-overcurrent characteristics shown in
Table 4.
Electromechanical disk reset capabilities are provided
for all time-overcurrent elements. The following time-
overcurrent elements are available in the SEL-787.
➤One maximum phase time-overcurrent (51P) element
per winding that operates on the maximum of the cor-
responding winding phase currents.
➤Three per-phase (A-, B-, and C-phase) time-overcur-
rent (51P) elements, one element per phase, that oper-
ate on the corresponding phase current of Winding 3
(only available on models with Winding 3).
➤One negative-sequence time-overcurrent (51Q) ele-
ment per winding that operates on the calculated neg-
ative-sequence current.
➤One residual time-overcurrent (51G) element per
winding that operates on the calculated residual (3I0)
current.
➤One neutral time-overcurrent (51N) element that
operates on the neutral current associated with the
neutral channel (MOT dependent).
Combined Time-Overcurrent Elements
The combined time-overcurrent elements can be used for
transformers connected to a ring-bus or breaker and one-
half systems. The SEL-787-4X/2E/3S models allow you
to combine Winding 1 and Winding 2 and/or Winding 3
and Winding 4 currents. The following combined time-
overcurrent elements are available:
➤Two phase time-overcurrent (51P) elements, one each
for combined Windings 1 and 2 and Windings 3
and 4, that operate on the maximum of the corre-
sponding combined phase currents.
➤Two zero-sequence time-overcurrent (51G) elements,
one each for combined Windings 1 and 2 and
Windings 3 and 4, that operate on the calculated zero-
sequence current of the corresponding combined cur-
rents.
Breaker Failure Protection
The SEL-787 offers breaker failure protection for as
many as four three-pole breakers. Use breaker failure
detection to issue retrip commands to the failed breaker
or to trip adjacent breakers using the relays contact out-
put logic or communications-based tripping schemes.
Breaker failure is initiated by the breaker failure initiate
(BFI) SELOGIC input. The BFI input is typically driven
by local and remote open/trip commands to the breaker.
Once the BFI input is received, the breaker failure
element monitors positive- and negative-sequence
current magnitudes and the breaker auxiliary contacts to
determine when to initiate the breaker failure delay timer.
If current or breaker auxiliary contact status does not
indicate an open breaker condition within the time set by
the breaker failure delay timer, the element issues a
breaker failure trip output.
Figure 6 Breaker Failure Protection
Volts/Hertz Protection
Overexcitation occurs when the magnetic core of a
power apparatus becomes saturated. When saturation
occurs, stray flux is induced in nonlaminated compo-
nents, which can result in overheating. By ordering the
voltage option for the SEL-787, you can add a volts/hertz
element to detect overexcitation. An SEL-787 with
optional voltage inputs provides a sensitive definite-time
delayed element, plus a tripping element with a compos-
ite operating time.
For example, the relay calculates the transformer
volts/hertz as a percentage of nominal, based on
measured values and the nominal voltage and frequency
settings. The relay starts a timer when the system voltage
causes an excursion that exceeds the volts/hertz
overexcitation setting. If the condition remains for the set
time delay, the relay asserts and typically provides an
alarm function. The element is supervised by the
SELOGIC torque control equation, which enables or
disables the element as required by the application.
Use the SEL-5806 Curve Designer Software to set the
user-defined curve (see Figure 7). For tripping, the relay
provides a time-integrating element with a settable
operating characteristic. You can set the relay element to
operate as an inverse-time element; a user-defined curve
element; a composite element with an inverse-time
Table 4 Inverse-Time Overcurrent Curves
U.S. (IEEE) IEC
Moderately Inverse Standard Inverse
Inverse Very Inverse
Very Inverse Extremely Inverse
Extremely Inverse Long-Time Inverse
Short-Time Inverse Short-Time Inverse
BFD
0
BFT
BFI
|I1| + |I2|
0.02 • INOM
52A
52ABF

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
11
characteristic and a definite-time characteristic; or a
dual-level, definite-time element.
For any of these operating characteristics, the element
provides a linear reset characteristic with a settable reset
time. The torque control setting also supervises this
element. The tripping element has a percent-travel
operating characteristic similar to one used by an
induction-disk, time-overcurrent element. This
characteristic emulates the heating effect of
overexcitation on transformer components.
Figure 7 SEL-5806 Volts/Hertz User Curve Design
Example
Over- and Undervoltage Protection
The SEL-787 with optional voltage inputs contains phase
over- and undervoltage and sequence overvoltage ele-
ments that help create protection and control schemes,
such as undervoltage load shedding or standby genera-
tion start/stop commands. All voltage elements provide
two pickup levels with definite-time delay settings. The
following over- and undervoltage elements are available:
➤Phase undervoltage (27P) and overvoltage (59P) ele-
ments that operate on the measured phase-to-neutral
voltages.
➤Phase-to-phase undervoltage (27PP) and overvoltage
(59PP) elements that operate on the measured
phase-to-phase voltages.
➤Negative-sequence overvoltage (59Q) and residual-
ground overvoltage (59G) elements that operate on
the calculated negative-sequence and residual-ground
voltage, respectively.
➤Phase undervoltage (27S) and phase overvoltage
(59S) elements that operate on VS channel voltage.
➤Inverse-time overvoltage (59I) and inverse-time
undervoltage (27I) elements that operate on the mea-
sured phase-to-neutral voltages, phase-to-phase volt-
ages, positive-sequence voltage, or VS channel
voltage.
Loss-of-Potential Detection
The SEL-787 with optional voltage inputs contains LOP
detection logic on the three-phase voltage input to the
relay. The LOP logic detects open voltage transformer
fuses or other conditions that cause a loss of relay sec-
ondary voltage input. The SEL-787 with optional voltage
inputs includes LOP logic that detects one, two, or three
potentially open fuses. This patented LOP logic is
unique, because it does not require settings and is univer-
sally applicable. The LOP feature allows for the blocking
of protection elements to add security during voltage
transformer fuse failure.
Synchronism Check/Station DC
Battery Monitor
The SEL-787-3S allows you to program the VS/Vbat
voltage channel for use as either a synchronism check or
station dc battery monitor. When programmed as a
synchronism-check channel, single-phase voltage
(phase-to-neutral or phase-to-phase) can be connected to
the voltage input for a synchronism check or hot/dead
line check across the circuit breaker to which the three-
phase voltages are assigned. When the channel is pro-
grammed for the battery monitor, the station dc battery
voltage can be monitored. The relay also allows you to
program over- and undervoltage elements on the voltage
channel.
Over- and Underfrequency Protection
The SEL-787 with optional voltage inputs contains four
frequency elements. Each element operates as either an
over- or underfrequency element with or without time
delay, depending on the element pickup setting.
If the element pickup setting is less than the nominal
system frequency setting, the element operates as an
underfrequency element, picking up if the measured
frequency is less than the set point. If the pickup setting
exceeds the nominal system frequency, the element
operates as an overfrequency element, picking up if the
measured frequency exceeds the set point.
The SEL-787 with optional voltage inputs uses the
positive-sequence voltage to determine system
frequency. All frequency elements are disabled if the
positive-sequence voltage is less than the minimum
voltage threshold.

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
12
Directional Power Element
Protection
The SEL-787 with optional voltage inputs provides two
directional power elements for detecting real (WATTS)
or reactive (VARS) directional power flow levels for the
transformer winding(s) associated with the three-phase
voltage input. Each directional power element has a
definite-time delay setting.
RTD Thermal Protection
When the SEL-787 is equipped with either an optional
10 RTD input expansion card or an external SEL-2600
RTD Module with as many as 12 RTD inputs, you can
program as many as 12 thermal elements in the relay for
two levels of thermal protection per element. Each RTD
input provides an alarm and trip thermal pickup setting in
degrees Celsius, open and shorted RTD detection, and is
compatible with the following three-wire RTD types:
➤PT100 (100 platinum)
➤NI100 (100 nickel)
➤NI120 (120 nickel)
➤CU10 (10 copper)
Operator Controls
Operator controls eliminate traditional panel control
switches. Eight conveniently sized operator controls,
each with two programmable tricolor LEDs, are located
on the relay front panel (see Figure 8, Figure 9, and
Figure 10). You can set the SER to track operator con-
trols. Use SELOGIC control equations to change operator
control functions. Use configurable labels to change all
of the text shown in Figure 8, Figure 9, and Figure 10.
Figure 8 Operator Controls (787-4X Model)
Figure 9 Operator Controls (787-3E/3S Models)
Figure 10 Operator Controls (787-2E/21/2X Models)
The following operator control descriptions are for
factory-set logic.
LOCK: The LOCK operator control blocks selected
functions. Press it for at least three seconds to engage or
disengage the lock function. When the LOCK pushbutton
is engaged, the CLOSE operator control is blocked.
BRKRn: Each of the BRKRn (n= 1, 2, 3, or 4) pushbuttons
allows you to select the breaker on which a close or trip
control operation is to be performed. Only one breaker
can be selected at any given time. Breaker select status
for a given breaker is indicated by the upper pushbutton
LED. The lower pushbutton LED indicates the
CLOSED/OPEN (RED/GREEN, respectively) status of
the corresponding breaker.
CLOSE and TRIP: Use the CLOSE and TRIP operator controls
to close and open the circuit breaker. You can program
these controls with intentional time delays to support
operational requirements for breaker-mounted relays.
This allows you to press the CLOSE or TRIP pushbutton,
then move to an alternate location before the breaker
command is executed.
BRKR4
SELECTED
CLOSED/OPEN
BRKR1
BREAKER CLOSING
CLOSE
BREAKER OPENING
TRIP
AUX1
SELECTED
BRKR2
SELECTED
CLOSED/OPEN
BRKR3
SELECTED
CLOSED/OPEN
CLOSED/OPEN
ENABLED
LOCK
DISABLED
ENABLED
LOCK
DISABLED
SELECTED
CLOSED/OPEN
BRKR1
BRKR2
SELECTED
CLOSED/OPEN
BRKR3
SELECTED
CLOSED/OPEN
BREAKER CLOSING
CLOSE
BREAKER OPENING
TRIP
AUX1
AUX2
ENABLED
LOCK
DISABLED
SELECTED
CLOSED/OPEN
BRKR1
BRKR2
SELECTED
CLOSED/OPEN
SELECTED
CLOSED/OPEN
BREAKER CLOSING
CLOSE
BREAKER OPENING
TRIP
AUX1
AUX2
AUX3

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
13
AUXn: You can program the AUXn (n= 1, 2, or 3)
pushbuttons for additional control of your specific
application.
In the SEL-787 with the touchscreen display, you can use
the front-panel operator control pushbuttons to jump to a
specific screen while also using them for
LOCK/TRIP/CLOSE operations, etc. You can program
the selectable operator pushbutton screen settings under
the Touchscreen settings category in QuickSet to map the
button to a specific screen.
Built-In Web Server
Every Ethernet-equipped SEL-787 relay includes a built-
in web server. Interface with the relay by using any stan-
dard web browser to perform the following actions:
➤Log in with password protection.
➤Safely read the relay settings.
➤Verify the relay self-test status and view the relay
configuration.
➤Inspect meter reports.
➤Download event reports.
➤Upload new firmware (firmware upgrade).
Figure 11 shows the fundamental metering screen that
can be accessed by clicking Meter >Fundamental. Use
the Meter menu to view all the available relay metering
statistics.
Figure 11 Fundamental Meter Report Webpage
Figure 12 shows the Group 1 settings webpage. You can
view the settings of each relay settings class by selecting
Settings and the respective relay settings class.
Figure 12 Group 1 Settings Webpage
You can upgrade the relay firmware through the relay
web server by clicking System >File Management
(available at Access Level 2) and selecting the firmware
upgrade file. Figure 13 shows the firmware upgrade
webpage.
Figure 13 Upgrade the Relay Firmware From the File
Management Webpage
Relay and Logic Settings Software
QuickSet simplifies settings and provides analytical
support for the SEL-787. There are several ways to
create and manage relay settings with QuickSet.
➤Develop settings offline with an intelligent settings
editor that only allows valid settings.
➤Create SELOGIC control equations with a drag-and-
drop text editor.
➤Configure proper settings using online help.
➤Organize settings with the relay database manager.
➤Load and retrieve settings using a simple PC commu-
nications link.
With QuickSet, you can verify settings and analyze
power system events with the integrated waveform and
harmonic analysis tools.
Use the following features of QuickSet to monitor,
commission, and test the SEL-787.
➤Use the HMI to monitor meter data, Relay Word bits,
and output contact statuses during testing.
➤Use the PC interface to remotely retrieve power sys-
tem data.

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
14
➤Use the Event Report Analysis tool for easy retrieval
and visualization of ac waveforms and digital inputs
and outputs the relay processes.
➤Use the graphical current phasor display in the HMI
to visualize differential current relationships.
➤Use bay control to design new bay screens and edit
existing bay screens by launching ACSELERATOR
Bay Screen Builder SEL-5036 Software for
SEL-787 relays with the touchscreen display.
ACSELERATOR Bay Screen Builder
SEL-5036 Software
The SEL-787 with the touchscreen display option pro-
vides you with the ability to design bay configuration
screens to meet your system needs. You can display the
bay configuration as a single-line diagram (SLD) on the
touchscreen. You can use ANSI and IEC symbols, along
with analog and digital labels, for the SLD to indicate the
status of the breaker and disconnects, bus voltages, and
power flow through the breaker. In addition to SLDs, you
can design the screens to show the status of various relay
elements via Relay Word bits or to show analog quanti-
ties for commissioning or day-to-day operations. You
can design these screens with the help of Bay Screen
Builder in conjunction with QuickSet. Bay Screen
Builder provides an intuitive and powerful interface to
design bay screens to meet your application needs.
Figure 14 Bay Screen Builder
Metering and Monitoring
The SEL-787 provides extensive metering capabilities.
See Specifications on page 34 for metering and power
measurement accuracies. As shown in Table 5, metered
quantities include phase voltages and currents; neutral
current; sequence voltages and currents; harmonics,
power, frequency, and energy; and maximum/minimum
logging of selected quantities. The relay reports all
metered quantities in primary quantities (current in
A primary and voltage in V primary).
e

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
15
Load Profile
The SEL-787 features a programmable Load Data Pro-
file (LDP) recorder that records as many as 17 metering
quantities into nonvolatile memory at fixed time inter-
vals. The LDP saves several days to several weeks of the
most recent data depending on the LDP settings
(9800 entries total).
Synchronized Phasor Measurement
Combine the SEL-787 with an SEL IRIG-B time source
to measure the system angle in real time with a timing
accuracy of ±10 µs. Measure instantaneous voltage and
current phase angles in real time to improve system oper-
ation with synchrophasor information. Replace state
measurement, study validation, or track system stability.
Use SEL-5077 SYNCHROWAVE®Server Software or
SEL-5078-2 SYNCHROWAVE®Central Visualization and
Analysis Software to view system angles at multiple
locations for precise system analysis and system-state
measurement (see Figure 15).
Table 5 SEL-787 Metered Values (Model Dependent)
Typ es of Meter ing
Instantaneous RMS Remote Analogs Energy
Math Variables Synchrophasors Max/Min Thermal
Demand and Peak Demand Analog Inputs
Quantity Description
Currents IxWn
(x=A,B,C,n=1,2,3,4)
Winding phase current magnitude and angle, primary A
IN Neutral current magnitude and angle, primary A
IGWn(n= 1, 2, 3, 4) Residual-ground fault current and angle per winding, primary A
3I2Wn(n= 1, 2, 3, 4) Negative-sequence current and angle per winding, primary A
IOPz(z= 1, 2, 3) Differential operate current, scaled to TAP
IRTz(z= 1, 2, 3) Differential restraint current, scaled to TAP
InF2, InF4, InF5 (n= 1, 2, 3, 4) Current harmonics, InF2/IOPn(%) for 2nd, 4th, 5th harmonics
Voltages VA, VB, VC Phase voltages and angles, primary volts, for wye-connected potential transformers
Voltages VAB, VBC, VCA Phase-to-phase voltages and angles, primary volts, for delta-connected potential transformers
Voltage VG Residual-ground voltage and phase angle, primary volts, for wye-connected potential transformers
Voltage 3V2 Negative-sequence voltage and phase angle, primary volts
Power kVA, kW, kVAR Calculated apparent, real, and reactive power scaled to primary values (single and three-phase)a
aSingle-phase power and power factor quantities are not available when delta-connected PTs are used.
Energy MWh, MVARh Three-phase positive and negative megawatt-hours, megavar-hours
Power Factor PF Single and three-phase power factor (leading or lagging)a
Voltage VS Synchronism-check voltage channel, voltage magnitude and angle, primary volts
Voltage VDC Station battery voltage
Frequency FREQ Measured system frequency (Hz)
Frequency FREQS Measured frequency (Hz) of synchronism-check channel
V/Hz Calculated volts/hertz in percent, using highest measured voltage and frequency
AIx01–AIx04 (x= 3, 4, or 5) Analog inputs
MV01–MV32 Math variables
RA001–RA128 Remote analogs
RTD1–RTD12 RTD temperature measurement (degrees C)

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
16
Figure 15 View of System Angle at Multiple Locations
Send synchrophasor data using IEEE C37.118-2005
protocol to SEL synchrophasor applications. These
include the SEL-3378 Synchrophasor Vector Processor
(SVP), SEL-3530 Real-Time Automation Controller
(RTAC), and the SEL-5078-2 SYNCHROWAVE®Central
Visualization and Analysis Software suite.
The SEL-3373 Station Phasor Data Concentrator (PDC)
and the SEL-5073 SYNCHROWAVEPDC software
correlate data from multiple SEL-787 relays and
concentrate the result into a single output data stream.
These products also provide synchrophasor data
archiving capability. These SEL-3378 SVP enables
control applications based on synchrophasors. Directly
measure the oscillation modes of your power system and
then act on the result. Use wide-area phase angle slip and
acceleration measurements to properly control islanding
of distributed generation. With the SVP, you can
customize a synchrophasor control application according
to the unique requirements of your power system.
The data rate of SEL-787 synchrophasors is selectable
with a range of 1–60 messages per second. This
flexibility is important for efficient use of
communication capacity.
The SEL-787 phasor measurement accuracy meets the
highest IEEE C37.118-2005 Level 1 requirement of 1
percent total vector error (TVE). This means you can use
any SEL-787 model in an application that otherwise
would require purchasing a separate dedicated phasor
measurement unit (PMU).
Use the SEL-787 with SEL communications processors,
or the SEL-3530 RTAC, to change nonlinear state
estimation into linear state estimation. If all necessary
lines include synchrophasor measurements then state
estimation is no longer necessary. The system state is
directly measured.
Figure 16 Synchrophasor Measurements Turn State
Estimation Into State Measurement
Improve Situational Awareness
Provide improved information to system operators.
Advanced synchrophasor-based tools produce a real-time
view of system conditions. Use system trends, alarm
points, and preprogrammed responses to help operators
prevent a cascading system collapse and maximize sys-
tem stability. Awareness of system trends provides opera-
tors with an understanding of future values based on
measured data.
➤Increase system loading while maintaining adequate
stability margins.
➤Improve operator response to system contingencies
such as overload conditions, transmission outages, or
generator shutdown.
➤Advance system knowledge with correlated event
reporting and real-time system visualization.
➤Validate planning studies to improve system load bal-
ance and station optimization.
Figure 17 Visualization of Phase Angle Measurements
Across a Power System
San Antonio, TX
60.0 Hz
Chicago, IL
60.015 Hz
Monterrey, Mexico
59.996 Hz 59.996 Hz
Pullman, WA Philadelphia, PA
Tampa, FL
60.003 Hz
60.007 Hz
Pullman
Chicago
Philadelphia
Tampa
San Antonio
Monterrey
δ
1
δ
2
V
1
V
2
V
1
V
2
P
12
Q
12
= h (V,θ)
State
= h (V,θ) + error
State
MeasurementsMeasurements
1 Second10 Minutes

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
17
Figure 18 SEL-5078 SYNCHROWAVEConsole Real-Time,
Wide-Area Visualization Tool
Event Reporting and SER
Event reports and the SER simplify post-fault analysis
and improve understanding of simple and complex pro-
tective scheme operations. In response to a user-selected
trigger, the voltage, current, frequency, and element sta-
tus information contained in each event report confirms
relay, scheme, and system performance for every fault.
Decide how much detail is necessary when you request
an event report (e.g., 1/4-cycle or 1/32-cycle resolution,
filtered or raw analog data, respectively).
The relay stores as many as 5 of the most recent
180-cycle event reports, 18 of the most recent 64-cycle
event reports, or 50 of the most recent 15-cycle event
reports in nonvolatile memory. The relay always appends
relay settings to the bottom of each event report.
The following analog data formats are available:
➤1/4-cycle or 1/32-cycle resolution, filtered or unfil-
tered analog, ASCII or Compressed ASCII reports
➤1/4-cycle filtered analog, ASCII differential reports
➤1/32-cycle resolution COMTRADE reports
The relay SER feature stores the latest 1,024 entries. Use
this feature to gain a broad perspective at a glance. An
SER entry helps to monitor input/output change-of-state
occurrences and element pickup/dropout.
Synchronized Measurements
The IRIG-B time-code input synchronizes the SEL-787
internal clock time to within ±1 s of the time-source
input. Convenient sources for this time code are an
SEL-2401 Satellite-Synchronized Clock, an SEL
communications processor, or an SEL RTAC (via Serial
Port 3 on the SEL-787). For time accuracy specifications
for metering, synchrophasors, and events, see
Specifications.
Substation Battery Monitor
The SEL-787 relays that include the enhanced voltage
option with the monitoring package measure and report
the substation battery voltage connected to the VBAT ter-
minals. The relay includes two programmable threshold
comparators and associated logic for alarm and control.
For example, if the battery charger fails, the measured dc
falls below a programmable threshold. The SEL-787
alarms to alert operations personnel before the substation
battery voltage falls to unacceptable levels. Monitor
these thresholds with an SEL communications processor
and trigger messages, telephone calls, or other actions.
The measured dc voltage appears in the meter display
and the Vdc column of the event report. Use the event
report column data to see an oscillographic display of the
battery voltage. This display shows how much the
substation battery voltage drops during trip, close, and
other control operations.
Circuit Breaker Contact Wear
Monitor
Circuit breakers experience mechanical and electrical
wear every time they operate. Intelligent scheduling of
breaker maintenance takes into account the manufac-
turer’s published data of contact wear versus interruption
levels and operation count. With the breaker manufac-
turer’s maintenance curve as input data, the SEL-787
breaker monitor feature compares these input data to the
measured (unfiltered) ac current at the time of a trip and
the number of close-to-open operations.
Every time the breaker trips, the relay integrates the
measured current information. When the result of this
integration exceeds the breaker wear curve threshold
(see Figure 19), the relay alarms via output contact,
communications port, or front-panel display. This kind of
information allows timely and economical scheduling of
breaker maintenance.
Figure 19 Breaker Contact Wear Curve and Settings
Through-Fault Monitoring
A through fault is an overcurrent event external to the
differential protection zone. While a through fault is not
kA Interrupted
(Set Point 1)
(Set Point 2)
(Set Point 3)
Breaker Manufacturer's
Maintenance Curve
Close to Open Operations

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
18
an in-zone event, the currents required to feed this exter-
nal fault can cause great stress on the apparatus inside the
differential protection zone. Through-fault currents can
cause transformer winding displacement, leading to
mechanical damage and increased transformer thermal
wear. An SEL-787 through-fault event monitor gathers
current level, duration, and date/time for each through
fault. The monitor also calculates a simple I2t and cumu-
latively stores these data per phase. Use through-fault
event data to schedule proactive transformer bank main-
tenance and to help justify through-fault mitigation
efforts. Apply the accumulated alarm capability of the
relay to indicate excess through-fault current (I2t) over
time.
IEC 61850 Test Mode
Test mode allows you to test an in-service relay without
operating control output contacts. Test mode includes
five different modes.
On: In On mode, the relay operates as normal; it reports
IEC 61850 Mode/Behavior status as On and processes all
inputs and outputs as normal. If the quality of the sub-
scribed GOOSE messages satisfies the GOOSE process-
ing, the relay processes the received GOOSE messages
as valid.
Blocked: This mode is similar to On mode, except that
the device does not trip any physical contact output.
Test: In Test mode, the relay processes valid incoming
test signals and normal messages and operates physical
contact outputs, if the outputs are triggered.
Test/Blocked: This is similar to Test mode, except that
the device does not trip any physical contact outputs.
Off: The device does not process any incoming data or
control commands (except commands to change the
mode). All protection logic is disabled and all data qual-
ity is marked as invalid.
Touchscreen Display
You can order the SEL-787 Transformer Protection
Relay with an optional touchscreen display (5-inch,
color, 800 x 480 pixels). The touchscreen display makes
relay data metering, monitoring, and control quick and
efficient. The touchscreen display option in the SEL-787
features a straightforward application-driven control
structure and includes intuitive and graphical screen
designs.
The touchscreen display allows you to:
➤View and control bay screens
➤Access metering and monitoring data
➤Inspect targets
➤View event history, summary data, and SER informa-
tion
➤View relay status and configuration
➤Control relay operations
➤View and edit settings
➤Enable the rotating display
➤Program control pushbuttons to jump to a specific
screen
You can navigate the touchscreen by tapping the folders
and applications. The folders and applications of the
Home screen are shown in Figure 20. Folders and appli-
cations are labeled according to functionality. Additional
folder and application screens for the SEL-787 touch-
screen display option can be seen in Figure 21 through
Figure 30.
Figure 20 Home (Default FPHOME Screen)
Bay Screens Application
The SEL-787 with the touchscreen display option pro-
vides you with the ability to design bay configuration
screens to meet your system needs. The bay configura-
tion can be displayed as an SLD on the touchscreen. You
can create as many as 5 bay screens with as many as
4 controllable breakers, 16 controllable 2-position

Schweitzer Engineering Laboratories, Inc. SEL-787-2, -3, -4 Data Sheet
19
disconnects, and 2 controllable 3-position disconnects.
ANSI and IEC symbols, along with analog and digital
labels, are available for you to create detailed SLDs of
the bay to indicate the status of the breaker and discon-
nects, bus voltages, and power flow through the breaker.
Figure 21 shows the default SLD for the touchscreen dis-
play option.
Figure 21 Default Bay Screen
Meter Folder Applications
The applications in the Meter folder are part-number
dependent. Only those metering applications specific to
your part number appear in the Meter folder. Tapping an
application in the Meter folder shows you the report for
that particular application. Tap the Phasor application to
view the current and voltage phasors (see Figure 22).
Figure 22 Meter Phasors
Tap the Energy application to view the energy metering
quantities (see Figure 23). A reset feature is provided for
the Energy, Max/Min, Demand, and Peak Demand
applications. Tap the Reset button (see Figure 23) to
navigate to the reset confirmation screen. Once you
confirm the reset, the data are reset to zero.
Figure 23 Meter Energy
Tap the Differential application to view the operate and
restraint currents for each differential element (87) of
your transformer in multiples of TAP. Use these
quantities in conjunction with the phasors or
fundamental metering screen to visualize the differential
protection of your transformer and for commissioning
exercises.
Figure 24 Meter Differential
Reports Folder Applications
Tapping the Reports folder navigates you to the screen
where you can access the Events and SER applications.
Use these applications to view events and SERs. To view
the event summary (see Figure 25) of a particular event
record, tap the event record on the Event History screen.
You can also trigger an event from the Event History
screen.
Figure 25 Event Summary

SEL-787-2, -3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
20
Tap the Sequential Events Recorder application to view
a history of the SER reports (see Figure 26).
Figure 26 Sequential Events Recorder
Tapping the Trash button, shown in Figure 26, on the
Event History and Sequential Events Recorder screens
and confirming the delete action removes the records
from the relay.
Control Folder Applications
Tapping the Control folder navigates you to the screen
where you can access the Breaker Control, Output Puls-
ing, and Local Bits applications. Use the applications to
perform breaker control operations, pulse output contacts
(Figure 27), and control the local bits (Figure 28).
Figure 27 Digital Output Pulsing–Slot A
Figure 28 Local Bits
Device Info Folder Applications
Tapping the Device Info folder navigates you to the
screen where you can access specific device information
applications (Status, Configuration, and Trip & Diag.
Messages) and the Reboot application. Tap the Status
application to view the relay status, firmware version,
part number, etc. (see Figure 29).
Figure 29 Device Status
To view the trip and diagnostic messages, tap the Trip &
Diag. Messages application (see Figure 30). When a
diagnostic failure, trip, or warning occurs, the relay
displays the diagnostic message on the screen until it is
either overriden by the restart of the rotating display or
the inactivity timer expires.
Figure 30 Trip and Diagnostics