SEL SEL-487E Transformer Protection Relay
SEL-487E
Transformer Protection Relay
Protect and monitor transformers with the SEL-487E. It offers up to seven three-phase restraint inputs, three independent restricted earth fault (REF) protection elements, and two three-phase voltage inputs.
The SEL-487E limits transformer damage by responding to internal fault conditions in less than 1.5 cycles.
The relay also helps avoid catastrophic transformer failure by detecting turn-to-turn faults involving as little as 2 percent of the total winding.
You can minimize commissioning time and eliminate costly errors with included software that recommends matrix compensation settings.
Through-fault and thermal monitoring allow you to track transformer wear and schedule maintenance as necessary.
Breaker wear monitoring reduces inefficient and costly breaker maintenance, saving time and money.
The SEL-487E includes two differential elements as well as comprehensive feeder and distance protection, making it well suited for protecting a distribution substation or switchgear using a single device.

SEL-487E
Apply the SEL-487E-4. with its 6 voltage and 18 current terminals, as a station phasor measurement unit.
Transform the way you modernize your substation with optional Time-Domain Link (TiDL) technology or Sampled Values (SV)-based technology using IEC 61850-9-2 or IEC 61869-9.
Multiwinding Protection—Configure the SEL-487E for transformer differential protection in transformer applications using up to seven restraint currents.
This includes single transformers with tertiary windings.
Three independent REF elements provide protection of grounded-wye windings.
You can invert individual or grouped CT or PT polarities to account for field wiring or protection zone changes.
Sensitive Turn-to-Turn Fault Detection—Avoid catastrophic transformer failure by detecting turn-to-turn faults involving as little as 2 percent of the total winding with the patented negative-sequence differential element.
High-Speed, Adaptive Differential Protection—Implement a two-stage slope that automatically adapts to internal or external fault conditions, even with CT saturation and heavily distorted waveforms, for fast, sensitive, dependable, and secure differential protection. The adaptive differential element responds to internal fault conditions in less than 1.5 cycles.
Diverse Applications—Protect large transformers with breaker-and-a-half high- and low-side connections.
With a typical two-winding transformer application, you can use the remaining three-phase current inputs for feeder backup protection.
Generator Step-Up Transformer Protection—Protect generator step-up (GSU) transformers, and apply the built-in thermal elements for monitoring and protecting generator and transformer winding temperatures simultaneously.
Thermal elements require inputs from the SEL-2600 RTD Module.
Advanced Asset Monitoring—Track transformer wear with through-fault and thermal monitoring.
Advanced breaker monitoring helps reduce inefficient and costly breaker maintenance.
The SEL-487E can monitor substation dc power systems for out-of-tolerance voltage levels or excessive voltage ripple.
Pad-Mounted Switchgear Protection—Protect pad-mounted switchgear with low-energy analog (LEA) voltage inputs;
this helps you save in overall system costs by eliminating the need for amplification electronics between the line sensor and the relay.
Having fewer devices also leads to a simpler system, a reduction in labor costs, and the elimination of a possible point of failure.
Configurable Distance Protection—Apply up to four zones of phase and ground distance protection, using mho or quadrilateral characteristics. The SEL-487E distance elements can be applied as transmission line or transformer protection.
Dependable Backup Protection—Provide backup protection with phase-, negative-, and zero-sequence overcurrent elements and 21 configurable time-overcurrent elements.
The SEL-487E helps you quickly identify the faulted phase with faulted-phase indications for each overcurrent element.
Secure overcurrent elements for feeder protection by using the optional per-terminal second-harmonic-blocking feature.
You can set up breaker failure protection with subsidence detection to rapidly detect breaker open conditions and minimize system coordination times.
Centralized Protection and Control (CPC) Solution—Simultaneously protect multiple assets using differential elements for dedicated transformer and bus protection as well as comprehensive distance protection and feeder protection in one relay.
Familiar logic and settings in the SEL-487E ensure an easier transition when you deploy CPC solutions in your system.
Station Phasor Measurement Unit (PMU)—Improve power system quality using synchrophasors (IEEE C37.118) from all 24 analog channels in your relay.
Use synchrophasors over serial or Ethernet communications to easily detect reactive loop flows, turn state estimation into state measurement, and provide an early warning of potential system instability.
Implement real-time control and take action based on local and remote messages by configuring the SEL-487E to receive synchrophasor messages from up to two PMUs.
Digital Secondary System Technologies—SEL TiDL and SV-based solutions replace copper with fiber to increase safety, improve reliability, and limit the impact of an electromagnetic pulse.
Apply the SEL-487E-5 TiDL relay with the SEL-TMU TiDL Merging Unit in the field to provide remote I/O and digitize analog signals.
This simple point-to-point solution with a strong cybersecurity posture is easy to implement.
Apply the IEC-compliant SEL-487E-5 SV relay to receive SV data from a remote merging unit via a network, or use it as an SV merging unit to publish analog data to remote SV relays in the control house.
Improve system availability in SV applications with the Parallel Redundancy Protocol (PRP), the High-availability Seamless Redundancy (HSR) protocol, or seamless failover using a five-port Ethernet card.
Flexible Communications Options—Use small form-factor pluggable (SFP) transceivers for TiDL ports as well as process bus, station bus, and engineering access ports in the five-port Ethernet card.
Choose between single- and multimode communications options for increased flexibility.
All ports support 100 Mbps SFP transceivers, and process bus ports also support 1 Gbps SFP transceivers.