SEL SEL-787-2/-3/-4 Transformer Protection Relay

SEL-787-2/-3/-4 Transformer Protection Relay

The only compact platform with REF and

up to four-terminal differential protection

• LEA inputs support installations with low-energy voltage sensors,

Rogowski coils, and low-power current transformers (LPCTs).

• Dual-slope percentage differential protection with harmonic

blocking and restraint enhances security.

• User-configurable restricted earth fault (REF) element provides

sensitive ground-fault detection in grounded-wye transformers.

• The 5-inch, 800 � 480 color touchscreen display allows direct

monitoring and control of your system.

• An optional single-phase voltage input provides a synchronism

check or station battery monitor.

Key Features

Differential Protection

The SEL-787-2/-3/-4 provides dual-slope differential protection with

harmonic blocking and restraint for as many as four terminals and

provides as many as three independent REF elements for sensitive

ground-fault detection in grounded-wye transformers. Standard

overcurrent elements in the SEL-787-2/-3/-4 provide backup

protection, including phase, negative-sequence, residual-ground, and

neutral-ground elements. You can select breaker failure protection

for as many as four three-pole breakers.

Transformer Monitoring

Measure and track accumulated through-fault current levels, and use

optional 4 to 20 mA inputs or resistance temperature detector (RTD)

thermal inputs to monitor ambient, load tap changer (LTC) tank, or

transformer oil temperatures.

Flexible Communications

Advanced protocols support communications using legacy and

modern supervisory and control systems. These protocols include

IEC 61850 Edition 2. the Rapid Spanning Tree Protocol (RSTP),

EtherNet/IP, the IEEE 1588 Precision Time Protocol (PTP) (firmware

based), IEC 60870-5-103. the Parallel Redundancy Protocol (PRP),

Modbus (RTU and TCP/IP), the Simple Network Time Protocol (SNTP),

DNP3 (serial and LAN/WAN), ASCII, Telnet, and the File Transfer

Protocol (FTP). In addition, the IEC 61850 test mode in the

SEL-787-2/-3/-4 enables in-service testing, which reduces

commissioning time.

LEA Sensor Inputs

The SEL-787-2/-3/-4 can be ordered with low-energy analog (LEA)

inputs to support medium- and low-voltage applications that use

low-energy voltage sensors and Rogowski coils or other low-power

current sensors. Order your device with the combination of LEA

current and voltage inputs that suits your application.

Proven Hardware

With an operating temperature range of –40° to +85°C (–40° to

+185°F), SEL equipment is designed to work in harsh substation

environments and exceeds requirements for reliable operation in

the presence of vibration, electromagnetic interference, and other

adverse environmental conditions. Optional conformal coating

provides extra protection in caustic environments. In addition, the

SEL-787-2/-3/-4 is ATEX-certified and Underwriters Laboratories

(UL) Class I, Division 2-certified for use in hazardous and potentially

explosive environments

Model Features

SEL-787-2X

SEL-787-21

SEL-787-2E

SEL-787-3E

SEL-787-3S

SEL-787-4X

Windings Protected 2 2 2 3 3 4

CT/PT Inputs

Phase Voltage Inputs 0 0 3 3 3 0

Differential Current Inputs 6 6 6 9 9 12

Neutral Current 0 1 1 1 0 0

VS/VBAT Channel 0 0 0 0 1 0

Protection Elements

24 Volts/Hertz • • •

25 Synchronism Check •

27I

Inverse Time

Undervoltage

(Phase, Phase-to-Phase,

Sequential, Vsync)

• • •

27P

Undervoltage (Phase)

With Inverse

Characteristic

• • •

27PP Phase-to-Phase

Undervoltage • • •

27S VS Channel Undervoltage •

32 Directional Power • • •

49 RTDs • • • • • •

50N Neutral Overcurrent • • •

50 (P,G,Q,

BF)

Overcurrent (Phase,

Ground, Neg. Seq,

Breaker Failure)

• • • • • •

51 (P,G,Q)

Time-Overcurrent

(Phase, Ground,

Neg. Seq.)

• • • • • •

51N Neutral Time-

Overcurrent • • •

51PC Combined Winding

Phase Time-Overcurrent • • •

51GC

Combined Winding

Ground Time-

Overcurrent

• • •

59 (P,G,Q) Overvoltage (Phase,

Ground, Neg. Seq.) • • •

59I

Inverse Time

Overvoltage

(Phase, Phase-to-Phase,

Sequential, Vsync)

• • •

59S

Overvoltage

(Synchronism or Battery

Voltage)

•

81 (O,U) Over-/Underfrequency • • •

87 Phase Differential • • • • • •

Model Features

SEL-787-2X

SEL-787-21

SEL-787-2E

SEL-787-3E

SEL-787-3S

SEL-787-4X

Differential and REF Elements

Differential Protection Windings

(Standard) 2 2 2 3 3 4

REF Elements (Standard) 0 1 1 1 0 0

Differential Protection Windings

(Winding 3 Configured for REF) 2 2 3

REF Elements

(Winding 3 Configured for REF) 2 2 2

Additional Functions

85RIO SEL Mirrored Bits®

Communications • • • • • •

BF Breaker Failure • • • • • •

BW Breaker Wear Monitoring • • • • • •

DFR Event Reports • • • • • •

ENV SEL-2600 RTD Module

Support* • • • • • •

LDP  Load Data Profiling • • • • • •

LEA

LEA Voltage Sensor

Inputs and Rogowski

Coil/LPCT Inputs*

• • • • • •

LGC SELogic® Control

Equations • • • • • •

LOP Loss of Potential • • •

MET High-Accuracy Metering • • • • • •

RTD

10 Internal or

12 External (see ENV)

RTD Inputs*

• • • • • •

REF Restricted Earth Fault • • • • •

RTU Remote Terminal Unit • • • • • •

SER Sequential Events

Recorder • • • • • •

TFE Through-Fault Event

Monitor • • • • • •

PMU Synchronized Phasor

Measurement • • • • • •

WEB Web Server • • • • • •