SEL-487B-2 Bus Differential and
Breaker Failure Relay
Bus Differential and Breaker Failure Relay
With Sampled Values or TiDL Technology
Key Features and Benefits
The SEL-487B-2 Bus Differential and Breaker Failure Relay with Sampled Values (SV) or TiDL
bus-current differential protection, circuit-breaker failure protection, and backup overcurrent protection.
➤
High-Speed Differential Protection. Busbar differential protection operates in less than one cycle, which
increases system stability margins and reduces equipment damage.
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Six Differential Zones. Flexible zone selection and six differential zones provide protection for multiple busbar
applications.
➤
Failed CT Detection. The SEL-487B reliably indicates open and shorted CTs for alarming and/or blocking.
➤
CT Ratio Mismatch. Differential protection accommodates as high as 10:1 CT ratio mismatch without auxiliary CTs.
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External Fault Security. External fault detection logic secures differential protection for external faults with
minimal CT requirements.
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Overcurrent Elements. Instantaneous and inverse time-overcurrent elements can provide backup protection for
each terminal.
➤
Voltage Elements. Negative- and zero-sequence, over- and undervoltage elements can supervise the differential element.
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Three Check Zones. Three dedicated check zones in each relay can supervise complex bus differential schemes.
➤
Breaker Failure. Apply the relay to supply breaker failure protection for all supported breakers. Logic for breaker
failure retrip and initiation of transfer tripping is included.
➤
Ethernet Access. The 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.
➤
Serial Data Communication. The relay can communicate serial data through SEL ASCII, SEL Fast Message,
SEL Fast Operate, M
Schweitzer Engineering Laboratories, Inc.
®
B
, and DNP3 protocols.
IRRORED
ITS
®
Technology provides
SEL-487B-2 Data Sheet
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