"One SEL-487E takes care of a wide range of transformer protection needs. This relay provides three-phase transformer differential protection using between 2 and 5 three-phase restraint currents, along with 2 three-phase voltages, and 3 single-phase restricted earth fault channels."

— Jeff Pope, SEL Product Engineer

• Current Differential Protection For Two- to Five-Winding Transformers
  Uses a two-stage slope that adapts to internal or external fault conditions automatically, even with CT saturation and heavily distorted waveforms, for fast, sensitive, dependable, and secure differential protection.
• Additional Protection
  Apply two three-phase voltage inputs for over/undervoltage, frequency, and volts-per-hertz protection. Make any overcurrent element directional using voltage-polarized directional elements as torque control inputs to the overcurrent elements. Implement transformer and feeder backup protection using adaptive time-overcurrent (IDMT) elements with selectable operating quantity, programmable pickup, and time delay settings. Apply three independent restricted earth fault (REF) elements for sensitive ground fault detection in grounded wye transformer applications.
• Highly Secure and Dependable
  Provide maximum security during external faults and transformer magnetizing inrush conditions with combined harmonic blocking and restraint features. Detect turn-to-turn winding faults for as little as 2 percent of the total transformer winding with the negative sequence differential element.
• Monitoring and Asset Management
  Monitor critical substation assets with the IEEE C57.91 thermal model for mineral oil-immersed transformers. Advanced monitoring features include transformer through fault, substation battery voltage, and comprehensive breaker wear monitoring. Through-fault duty is recorded and accumulated for use in SELOGIC^® control equations or manual monitoring.
• Metering and Reporting
  Eliminate or reduce external recorder and metering requirements with oscillographic event reports (up to 5 seconds of 8 kHz event data), Sequential Events Recorder (SER) reporting, and accurate three-phase power metering. Apply these powerful tools to simplify post-fault analysis and improve your understanding of simple and complex protective scheme operations. The relay aids in testing and troubleshooting settings and protection schemes.
• A Wide Variety of Flexible Communications
  Choose from the following:
  • An Ethernet card option provides two copper or fiber ports for failover redundancy.
  • Available Ethernet communications protocols include FTP, Telnet, DNP3 LAN/WAN, IEC 61850, and IEEE C37.118 synchrophasors.
  • All four independent EIA-232 serial ports support SEL Fast Message, SEL ASCII, Compressed ASCII, SEL Fast Operate, SEL Fast Meter, SEL Fast SER, enhanced SEL MIRRORED BITS^® communications, DNP3 Level 2 Slave plus dial-out, Virtual Terminal, and communications with SEL-2600 Series RTD Modules.

• Conformal Coating
  Protect equipment from harsh environments and airborne contaminants such as hydrogen sulfide, chlorine, salt, and moisture.
  Learn more about conformal coating.
• Rugged Design
  Trust the industry’s widest ambient operating temperature range, –40° to +85°C (–40° to +185°F).

• Front-Panel One-Line Diagrams Control and Monitoring
  Select your own system bay configuration, and control as many as five breakers and eight disconnect switches using the built-in mimic diagrams that include up to six programmable analog quantities for readouts as shown on the high- and the low-voltage diagrams below.

• Automation and Control
  Apply SEL-487E control logic to replace:
  • Traditional panel control switches
  • RTU-to-relay wiring
  • Traditional latching relays
  • Traditional indicating panel lights
  Implement SELOGIC control equations with SELOGIC variables, timers, latch bits, and remote control elements for customizing advanced protection and control schemes.

• ACSELERATOR^® QuickSet^® Software
  Develop relay settings offline, program SELOGIC control equations, and analyze post-fault event reports.

• ACSELERATOR Report Server SEL-5040 Software
  Automatically gather relay event reports on your PC and manage them with a database.
• SEL-5010 Relay Assistant Software
  Communicate with and manage SEL relay settings across your system.
• ACSELERATOR Analytic Assistant SEL-5601 Software
  Display oscillograms and vector diagrams to analyze event reports.
• Commissioning Assistant Software
  Minimize commissioning time with the first relay software that automatically identifies incorrect field wiring and improper CT configurations, and recommends corrections.

• Configure the SEL-487E for transformer differential protection in transformer applications using up to five windings. This includes single transformers with tertiary windings. Use three independent REF elements for protection of grounded wye windings.
• Configure the SEL-487E in a typical two-winding transformer application, and use the remaining three-phase current inputs for feeder backup protection.
• Protect generator step-up (GSU) transformer applications, and apply the built-in thermal elements for monitoring both generator and transformer winding temperatures simultaneously. Apply the volts-per-hertz element with two level settings for overexcitation protection of loaded and unloaded generator operating conditions. Set the directional power elements to detect forward and reverse power flow conditions for monitoring and protection of the GSU transformer in prime power, standby, base load, and peak shaving applications.
• Provide backup protection with phase, negative, and zero sequence overcurrent elements. Set up breaker failure protection with subsidence detection to rapidly detect breaker failure and minimize system coordination times.
• Implement the voltage inputs for voltage-based protection elements and frequency tracking from 40.1 to 65.0 Hz. Over- and undervoltage and frequency elements, along with volts-per-hertz elements, provide accurate transformer protection for off-frequency events and overexcitation conditions.

Budgetary Retail, Quantity 1: $6,750
(Prices displayed are for planning purposes and are subject to change. Contact your SEL sales representative today for a quote on configurations and quantities to meet your needs.)

Advanced Transformer Protection and Monitoring

SEL-487E Data Sheet (preliminary)