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 inputs for comprehensive transformer protection. 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.
Front- and Rear-Panel Diagrams
Standard Protection Features
Two-winding dual-slope differential protection with harmonic blocking and restraint. Phase, negative-sequence, residual-ground, and neutral-ground overcurrent elements for backup protection. Breaker failure protection for two three-pole breakers.
Optional Protection Features
Use the SEL-787 with optional voltage inputs to 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. In addition, use Sensitive Restricted Earth Fault (REF) protection for grounded-wye transformers.
Use transformer through-fault monitoring to measure accumulated through-fault levels of the transformer. Monitor ambient, load tap-changer (LTC) tank and transformer oil temperature using optional 4–20 mA or RTD thermal inputs.
Four programmable front-panel pushbuttons each with two programmable LEDs allow for a wide variety of uses, including easy trip and close control and status indications for a breaker. Implement local and remote operator control schemes using 32 local and 32 remote control bits.
Relay and Logic Settings Software
ACSELERATOR QuickSet® SEL-5030 Software reduces engineering costs for relay settings and logic programming. Tools in ACSELERATOR QuickSet make it easy to develop SELOGIC® control equations. Use the built-in phasor display to verify proper CT polarity and phasing.
Metering and Reporting
Built-in metering functions 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.
Additional Standard Features
Includes Modbus® RTU, Event Messenger support, MIRRORED BITS® communications, load profile, support for 12 external RTDs (SEL-2600 series module), IRIG-B input, advanced SELOGIC, configurable labels, IEEE C37.118-compliant synchrophasor protocol, and SEL-2812 compatible ST® connectors fiber-optic serial port.
Select from a wide offering of optional features, including IEC 61850, Modbus TCP/IP, Simple Network Time Protocol (SNTP), DNP3 LAN/WAN, DNP3 Serial, 10 internal RTDs, expanded digital/analog I/O, voltage inputs, additional EIA-232 or EIA-485 communications ports, and single or dual, copper wire or fiber-optic Ethernet ports.