Description

The SEL-487E Transformer Protection Relay provides three-phase differential protection for transformer applications
with as many as six three-phase restraint current inputs. A second three-phase differential element is also supported for
busbar protection.
➤ High-Speed Differential Protection. A two-stage slope adapts automatically to external fault conditions, providing
fast, sensitive, dependable, and secure differential protection, even for CT saturation and heavily distorted waveforms.
Two independent differential zones are available, one of which supports additional features that accommodate
transformer differential protection.
➤ Inrush and Overexcitation Detection. Combined harmonic blocking and restraint features provide maximum
security during transformer magnetizing inrush conditions. Waveshape-based inrush detection addresses inrush
conditions that contain low second and fourth harmonic content.
➤ Turn-to-Turn Winding Fault Protection. Innovative negative-sequence differential elements provide transformer
windings protection from as little as two percent turn-to-turn winding faults.
➤ Restricted Earth Fault Protection. Three independent REF elements provide sensitive protection for faults close to the winding neutral in grounded wye-connected transformers.
➤ Combined Overcurrent. Configurations exist for a wide variety of transformer applications. Use the combined
overcurrent elements for transformers connected to ring-bus or breaker and one-half systems. This feature
mathematically sums two terminal current inputs to form a single operating quantity.
➤ Distance Protection. Mho or quadrilateral characteristics protect transformers and transmission lines with four
zones of phase distance and ground distance elements. Line harmonic blocking, load-encroachment, coupling
capacitor voltage transformer (CCVT) detection, and out-of-step blocking logic add security to your distance
protection scheme.
➤ Transformer and Feeder Backup Protection. Adaptive time-overcurrent elements with selectable operating
quantity, programmable pickup, and time-delay settings provide transformer and feeder backup protection.
➤ Second-Harmonic Blocking for Feeder Protection. You can order the second-harmonic blocking option to
secure feeder protection elements during inrush conditions. This option provides second-harmonic calculations for
each individual terminal in addition to transformer differential harmonic blocking elements.
➤ Reclosing Control. You can incorporate programmable three-pole trip and reclose of as many as six independent
breakers into an integrated substation control system.
➤ Reverse Power Flow and Overload Condition Protection. The SEL-487E directional real- and reactive-power
elements guard against reverse power flow and overload conditions.
➤ Synchronism Check. Synchronism check can prevent circuit breakers from closing if the corresponding phases
across the open circuit breaker are excessively out of phase, magnitude, or frequency. The synchronism-check
function has a user-selectable synchronizing voltage source and incorporates slip frequency, two levels of maximum
angle difference, and breaker close time into the closing decision.
➤ Input/Output Scaling. The SEL-2600 RTD Module provides as many as 12 temperature inputs, and the
SEL-2505/SEL-2506 Remote I/O Modules provide a scalable number of discrete I/O points.
➤ Two CT Input Levels. Selectable 1 A or 5 A nominal secondary input levels are available for any three-phase
winding input.
➤ Large CT Mismatch Ratio. The relay can accommodate CT ratio mismatch as great as 35:1.
➤ Breaker Failure. High-speed (less than one cycle) open-pole detection logic reduces coordination times for critical
breaker failure applications. Apply the relay to supply breaker failure protection for all supported breakers. Logic
for breaker failure retrip and initiation of transfer tripping is included.
➤ IEC 60255-149 Compliant Thermal Model. The relay can provide a configurable thermal model for the protection
of a wide variety of devices. This function can activate a control action or issue an alarm or trip when equipment
overheats as a result of adverse operation conditions. A separate resistance temperature detector (RTD) module is
required for this application.
➤ Ethernet Access. The optional Ethernet card grants access to all relay functions. Use IEC 61850 Manufacturing
Message Specification (MMS) or DNP3 protocol directly to interconnect with automation systems. You can also
connect to DNP3 networks through a communications processor. Use File Transfer Protocol (FTP) for high-speed data
collection. Connect to substation or corporate LANs to transmit synchrophasors by using TCP or UDP internet protocols.
➤ Serial Data Communication. The relay can communicate serial data through SEL ASCII, SEL Fast Message,
SEL Fast Operate, MIRRORED BITS®, and DNP3 protocols. Synchrophasor data are provided in either SEL Fast
Message or IEEE C37.118 format.
➤ Automation. The enhanced automation features include programmable elements for local control, remote control,
protection latching, and automation latching. Local metering on the large front-panel LCD eliminates the need for
separate panel meters. Serial and Ethernet links efficiently transmit key information, including metering data, protection
element and control I/O status, synchrophasor data, IEC 61850 GOOSE messages, Sequential Events Recorder
(SER) reports, breaker monitoring, relay summary event reports, and time synchronization. Apply expanded
SELOGIC® control equations with math and comparison functions in control applications. Incorporate as many as
1000 lines of automation logic to accelerate and improve control actions.
➤ Synchrophasors. You can make informed load dispatch decisions based on actual real-time phasor measurements
from relays across your power system. Record streaming synchrophasor data from the relay for system-wide disturbance
recording. Control the power system by using local and remote synchrophasor data.
➤ Breaker and Battery Monitoring. You can schedule breaker maintenance when accumulated breaker duty
(independently monitored for each pole) indicates possible excess contact wear. The relay records electrical and
mechanical operating times for both the last operation and the average of operations since function reset. Alarm
contacts provide notification of substation battery voltage problems (as many as two independent battery monitors
in some SEL-400 series relays) even if voltage is low only during trip or close operations.
➤ Six Independent Settings Groups. The relay includes group logic to adjust settings for different operating conditions,
such as station maintenance, seasonal operations, emergency contingencies, loading, source changes, and adjacent
relay settings changes. Select the active group settings by control input, command, or other programmable conditions.
➤ Software-Invertible Polarities. Inverting individual or grouped CT and PT polarities allows you to account for
field wiring or zones of protection changes. CEV files and all metering and protection logic use the inverted polarities,
whereas COMTRADE event reports do not use inverted polarities but rather record signals as applied to the relay.
➤ Parallel Redundancy Protocol (PRP). PRP provides seamless recovery from any single Ethernet network failure.
The Ethernet network and all traffic are fully duplicated with both copies operating in parallel.
➤ IEC 61850 Operating Modes. The relay supports IEC 61850 standard operating modes such as Test, Blocked,
On, and Off.
➤ IEEE 1588, Precision Time Protocol (PTP). PTP provides high-accuracy timing over an Ethernet network.
➤ Digital Relay-to-Relay Communications. MIRRORED BITS communications can monitor internal element conditions
between bays within a station, or between stations, using SEL fiber-optic transceivers. Send digital, analog, and
virtual terminal data over the same MIRRORED BITS channel.
➤ Sequential Events Recorder (SER). The SER records the last 1000 events, including setting changes, startups,
and selectable logic elements.
➤ Oscillography and Event Reporting. The relay records voltages, currents, and internal logic points at a sampling
rate as fast as 8 kHz. Offline phasor and harmonic-analysis features allow investigation of bay and system
performance. Time-tag binary COMTRADE event reports with high-accuracy time stamping for accuracy better
than 10 μs.
➤ Digitally Signed Upgrades. The relay supports upgrading the relay firmware with a digitally signed upgrade file.
The digitally signed portion of the upgrade file helps ensure firmware and device authenticity after it is sent over a
serial or Ethernet connection.
➤ Increased Security. The relay divides control and settings into seven relay access levels; the relay has separate
breaker, protection, automation, and output access levels, among others. Set unique passwords for each access level.
➤ Rules-Based Settings Editor. You can communicate with and set the relay by using an ASCII terminal or use
QuickSet to configure the relay and analyze fault records with relay element response. Use as many as 200 aliases
to rename any digital or analog quantity in the relay