SEL-787 Transformer Protection Relay
Protect and monitor most industrial transformer applications with the versatile SEL-787 Transformer Protection Relay. Apply 2 three-phase winding inputs, and an optional single-phase restricted earth fault input and three-phase voltage input. Benefits include advanced automation and flexibility, single or dual, copper or fiber Ethernet communications ports, asset management data, and easy retrofit of most electromechanical relays.
- Two-Winding Current Differential, Overcurrent and Breaker Failure Protection
Apply two-winding dual-slope differential protection with phase, negative sequence, residual, and neutral overcurrent elements for backup protection. Use breaker failure protection for two three-pole breakers. - Secure and Dependable
Provide maximum security during external faults and transformer magnetizing inrush conditions. Detect internal faults quickly, during energization or normal operating conditions, using combined harmonic blocking and restraint differential elements.
Transformer Monitoring
Record and accumulate through-fault duty for use in SELogic® control equations or manual monitoring. Monitor ambient, load tap-changer (LTC) tank and transformer oil temperature with optional 4–20 mA analog inputs or RTD thermal inputs to extend the life of your transformers.
- Operator Control
Use four programmable front-panel pushbuttons each with two programmable LEDs for a wide variety of applications, including easy trip-and-close control and status indications for a breaker. 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. 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. 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. The printed circuit boards are conformal coated to provide an additional barrier to airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
Provide differential and overcurrent protection for two-winding:
- power transformers
- generator step-up transformers
- autotransformers
- Apply the optional single-phase CT channel along with the RTD thermal elements to provide fan bank control and protection.
- Implement additional RTD thermal elements to monitor load tap changer (LTC) tank temperatures and SELogic programming to indicate temperature differential alarms between transformer and LTC tank temperatures.
- Monitor the number of through-faults, accumulated I2t, and fault duration times to determine the frequency (through-fault events per day, week, month, or year) and impact of external faults on the transformer.
- Apply SEL-787 comprehensive reporting to diagnose events, schedule knowledge-based maintenance, detect unfavorable temperature trends, and satisfy information requirements of supervisory systems.
- Select the external RTD module (SEL-2600A or SEL-2600D) to eliminate expensive wire pulls and reduce wiring terminations at the relay by as much as 40 percent, while acquiring clean RTD signals and an additional contact input.
- Apply SEL Synchrophasors (IEEE C37.118) to turn state estimation into state measurement, and to provide early warning of potential system instability.
- Implement Mirrored Bits® communications for enhanced teleprotection and remote control.
- Advanced Protection
Protect grounded-wye transformers with sensitive restricted earth fault (REF) elements. Provide volts/hertz protection with frequency tracking from 20 to 70 Hz for generator step-up and other variable frequency applications. Implement load shedding and other control schemes with over- and underfrequency and over- and undervoltage elements. Flexible and Easy Communications
Apply copper or fiber, single or dual fiber Ethernet (DNP3, IEC 61850, Modbus), and up to 4 serial ports.
Flexible I/O for Local Control and System Applications
The base unit includes three digital outputs and two digital inputs. There are three card slots for optional SELect I/O cards including the following:
- 3 digital inputs / 4 digital outputs / 1 analog input (3 DI / 4 DO / 1 AI)
4 digital inputs / 4 digital outputs (4 DI / 4 DO)
4 analog inputs / 4 analog outputs (4 AI / 4 AO)
8 digital inputs (8 DI)
Serial communication (EIA-232 / EIA-485)
DeviceNet™ communication
10 internal RTD inputs (or add 12 external RTD inputs with an SEL-2600 RTD Module)
Neutral ac current input with three-phase ac voltage inputs (1 ACI / 3 AVI)
Neutral ac current input (1 ACI)
Conformal Coating
Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
Learn more about conformal coating.
- Projection Mounting Collars available in 45 and 90 mm.
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Find other mounting options with the SEL Mounting SELector
- Commissioning Assistant Software
Minimize commissioning time with the first relay software that recommends matrix compensation settings, after automatically identifying incorrect field wiring and improper CT configurations (incorrect CT polarities, inconsistent CT ratios, or crossed phases).
SEL University Training
- APP 787: SEL-787 Transformer Protection Relay
This two-day course provides hands-on application and step-by-step settings guidance for the SEL-787 transformer protection relay.
- COM 403: IEC 61850 Technology
- IEC 61850 was created to be an internationally standardized method of
communication and integration and to support systems built from
multivendor intelligent electronic devices (IEDs) that are networked to
perform protection, monitoring, automation, metering, and control
functions. In this communications fundamentals course, you will learn
about the components and protocols that make up the IEC 61850 standard.
During this one-day course, you will walk through the IEC 61850 planning
process and identify key network considerations. This course also
provides a concise introduction to the concepts that will be applied in
SYS 403.
- SYS 403: Practical IEC 61850 Application
- The international standard IEC 61850 was designed to standardize
communications and integration methods and to support systems built from
multivendor intelligent electronic devices (IEDs) that are networked to
perform protection, monitoring, automation, metering, and control
functions. SYS 403 is designed to be interactive and activity based.
During this course, you will configure and implement a realistic IEC
61850 communications and automation scheme. Each unit of this course
will guide you, step-by-step, through configuring this comprehensive
communications and automation scheme.
Flyers
Data Sheets
Guideform Specification
Installation Guides
Instruction Manuals
Instruction Sheets
Settings Sheets
Label Instruction
SELect Input Output Card Installation Instructions
Related Downloads
For file compatibility between the DeviceNet protocol and SEL relay firmware, refer to Appendix A of the product manual.
Certificates
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From the Product Configuration page, configure your product or enter your part number via the Universal Part Number Reverse Lookup. Then download custom .dwg or .pdf files specific to your product.
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