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*
Σ
51
51
P
G
87
87
Overcurrent
Time-Overcurrent
Undervoltage
Overvoltage
32
32
24
24
81
81
O
U
Volts/Hertz
Frequency
LOP
LOP
27P
27P
59
59
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 SEL
OGIC
Control Equations
• 32 Programmable Display Messages
• M
IRRORED
B
ITS
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
25
25
27S
27S
59S
59S
27I
27I
59I
59I
Inverse-Time
Undervoltage
Inverse-Time
Overvoltage