html{display:none} SEL-787-2/-3/-4 Transformer Protection Relay | Schweitzer Engineering Laboratories

SEL-787-2/-3/-4

Transformer Protection Relay

Protect and monitor most two-, three-, and four-winding transformers with the versatile SEL-787 platform. It provides advanced automation and flexibility, asset management data, and easy retrofitting of most electromechanical relays. The 5-inch, 800 × 480 color touchscreen display option allows you to directly set, monitor, and control your system from the relay front panel.

The SEL-787-2E/-21/-2X models offer two-winding differential protection, and the SEL-787-3E/-3S models offer three-winding differential protection. Select the SEL-787-4X for current-based four-winding differential protection.

SEL-787 Family Comparison Chart

Starting At

$2,950 USD

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Multiwinding Protection—Select the SEL-787 for standard dual-slope differential protection with harmonic blocking and restraint for most two-, three-, and four-winding transformers. The SEL-787 offers as many as three independent restricted earth fault (REF) elements for sensitive ground-fault detection in grounded-wye transformers. The relay also comes with a variety of overcurrent elements for backup protection, including phase, negative-sequence, residual-ground, and neutral-ground elements. Breaker failure protection for as many as four 3-pole breakers is also standard.

Frequency Tracking—Choose the SEL-787 for generator step-up and variable-frequency applications. The relay has voltage inputs to provide volts/hertz protection with frequency tracking from 20 to 70 Hz. Over-/underfrequency and over-/undervoltage elements allow you to implement load shedding and other control schemes with the relay.

Synchronism Check/Station DC Battery Monitor—Program the VS/VBAT voltage channel in the SEL-787-3S to perform a synchronism check across a circuit breaker or to monitor dc voltage levels of the substation battery.

Through-Fault Monitoring and Protection—Measure accumulated through-fault levels with the transformer through-fault monitor. Additionally, the optional 4–20 mA or resistance temperature detector (RTD) thermal inputs can monitor ambient, load tap changer (LTC) tank, and transformer oil temperatures.

Metering and Reporting—Eliminate separately mounted metering devices with the built-in metering functions. You can analyze Sequential Events Recorder (SER) reports and oscillographic event reports for rapid commissioning, testing, and post-fault diagnostics. You can also transfer event files in COMTRADE and CEV formats and transfer CID files, settings, and reports. The unsolicited SER protocol allows station-wide collection of binary SER messages.

Local/Remote Operator Controls—Employ eight programmable front-panel pushbuttons, each with two programmable tricolor LEDs, for a wide variety of uses, including easy trip/close control and status indication for all the breakers. With the operator control interface pushbuttons, you can easily implement local and remote operator control schemes using 32 local and 32 remote control bits. SELogic control equations and slide-in, configurable front-panel labels allow you to change the function and identification of target LEDs and operator control pushbuttons and LEDs.

Integration and Automation—Select from a wide array of communications protocols and media to support all your integration and automation solutions. You can quickly integrate the SEL-787 into serial- or Ethernet-based communications schemes with IEC 61850 Edition 2, IEC 60870-5-103, the IEC 62439 Parallel Redundancy Protocol (PRP), Mirrored Bits communications, Modbus, DNP3, and other protocols. You can choose English or Spanish front panels, with optional Spanish language support in the PC software, ASCII ports, and HMI.

Touchscreen Display Features and Functions

787 home

With a simple tap, quickly access bay screens, metering, and monitoring data, reports, settings, and more.

Touchscreen Display Features and Functions

787 bay screen

Select from predefined bay screens, or configure your own. Control a single breaker, monitor as many as five disconnect switches, and view analog and digital data in a contextual display.

Touchscreen Display Features and Functions

787 breaker

Verify breaker and disconnect changes using the secure control interface.

Touchscreen Display Features and Functions

787 authentication

Use the onscreen keyboard to quickly and easily enter passwords, search for Relay Word bits, and enter settings.

Touchscreen Display Features and Functions

787 power

Display the real, reactive, and apparent energy metering quantities imported and exported in a system. Easily reset the values via the display, and record the time and date of reset.

Touchscreen Display Features and Functions

787 phasors

View a graphical and textual represetnation of the real-time voltages and currents in a power system. Analyze the phasors to determine power system conditions.

Touchscreen Display Features and Functions

787 energy

Display the real, reactive, and apparent energy metering quantities imported and exported in a system. Easily reset the values via the display, and record the time and date of reset.

Touchscreen Display Features and Functions

787 SER2

Easily review the time-stamped SER data, including whether or not the Relay Word bit asserted or deasserted, during root-cause analysis of an event.

Overview

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Videos

How to Use the SEL-700 Series Color Touchscreen Display

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How to Use the SEL-700 Series Color Touchscreen Display

How to Set SEL-700 Series Bay Screen Settings

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How to Set SEL-700 Series Bay Screen Settings

Two-, Three-, and Four-Winding Current Differential, Overcurrent, Voltage, and Breaker Failure Protection
Apply two-, three-, or four-winding dual-slope differential protection with phase, negative-sequence, residual, and neutral overcurrent elements for backup protection. You can set elements in SEL-787-3E/-3S models for voltage- and frequency-based protection. Breaker failure protection for as many as four three-pole breakers comes standard.

Security and Dependability
Provide maximum security during external faults and transformer magnetizing inrush conditions. The SEL-787 can detect internal faults quickly during energization or normal operating conditions by using combined harmonic-blocking and harmonic-restraint differential elements.

Transformer Monitoring
Set the SEL-787 to record and accumulate through-fault duty for use in SELogic control equations or manual monitoring. In addition, you can monitor ambient, LTC tank, and transformer oil temperatures with optional 4–20 mA analog inputs or RTD thermal inputs to extend the life of your transformer.

Operator Control
Use eight programmable front-panel pushbuttons, each with two programmable, tricolored LEDs, for a wide variety of applications, including easy trip-and-close control and status indications for a breaker. You can implement local and remote operator control schemes with 32 local and 32 remote control bits.

Metering and Reporting
Eliminate separately mounted metering devices with built-in metering functions. You can analyze SER reports and oscillographic event reports in COMTRADE and CEV formats to analyze post-fault diagnostics and for rapid commissioning and testing. You can retrieve COMTRADE files via Ethernet FTP or IEC 61850 MMS, and the unsolicited SER protocol allows station-wide collection of binary SER messages. SEL-787 metered quantities include harmonics, power, frequency, and energy; phase voltages and currents; neutral currents; sequence voltages and currents; and maximum/minimum logging of selected quantities.

Rugged Design
Trust the industry’s widest ambient operating temperature range, –40° to +85°C (–40° to +185°F). The SEL-787 withstands vibration, electrical surges, fast transients, and extreme temperatures, meeting stringent industry standards. A conformal coating option for the printed circuit boards provides an additional barrier to airborne contaminants, such as hydrogen sulfide, chlorine, salt, and moisture.

Input Options
The SEL-787 platform provides a range of current and voltage inputs that allow you to customize a protection solution to fit your transformer application.

  • SEL-787-2X: 6 differential current inputs
  • SEL-787-21: 6 differential current inputs, 1 neutral current input
  • SEL-787-2E: 6 differential current inputs, 3 phase voltage inputs, 1 neutral current input
  • SEL-787-3E: 9 differential current inputs, 3 phase voltage inputs, 1 neutral current input
  • SEL-787-3S: 9 differential current inputs, 3 phase voltage inputs, 1 voltage input (Vsynch or Vbattery)
  • SEL-787-4X: 12 differential current inputs

Flexible I/O and Current/Voltage Inputs for Local Control and System Applications
The base system includes three digital outputs (DO) and two digital inputs (DI). There are three card slots for optional cards, including the following:

  • 4 ac current inputs and 3 three-phase ac voltage inputs (4 ACI/3 AVI)
  • 2 three-phase ACI (6 ACI)
  • 1 neutral ACI with 3 three-phase AVI 
  • 1 neutral ACI
  • 4 DO, 3 DI, and 1 analog output (AO)
  • 4 DI and 3 DO 
  • 4 DI and 4 DO
  • 4 analog inputs (AI) and 4 AO
  • 8 DO
  • 8 DI
  • 14 DI
  • 10 RTD inputs

Integrated Communications
The SEL-787 offers many communications media and protocol options. Versatile communications options provide fast integration into both new and existing applications.

  • Communications Media
    • Ethernet 10/100BASE-T
    • Ethernet 100BASE-FX
    • Single or dual Ethernet ports
    • EIA-232 serial
    • EIA-485 serial
    • Fiber-optic serial multimode ST
  • Communications Protocols
    • Mirrored Bits communications
    • IEC 61850 Edition 2
    • IEC 60870-5-103
    • IEC 62439 PRP for models with dual Ethernet
    • DNP3 LAN/WAN
    • DNP3 Serial
    • Modbus TCP
    • Modbus RTU
    • Telnet
    • FTP
    • IEEE C37.118 synchrophasors
    • Simple Network Time Protocol (SNTP)

Languages
An ordering option is available for English or Spanish language support.

Retrofit Replacement Kits
Replace existing protective relays with the SEL-787 by using the applicable mounting kits. These kits provide the parts needed to easily replace many older protective relays with the SEL-787. You can find other mounting options with the SEL Mounting Selector.

Projection Mounting
Projection, flush and easily extractable mounting solutions are available.

Conformal Coating
Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture. Learn more about conformal coating.

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Drawings

Minimum QuickSet Version

Minimum QuickSet Version