The SEL-487B provides optimized, low-impedance bus differential fault detection by using high-speed, subcycle protection coupled with high-security operation for external faults. Superior protection performance is combined with integrated station automation features for seamless transition into new and retrofit applications. Optional Time-Domain Link (TiDL) technology transforms the way you modernize your substation.

Low-Impedance Bus Differential Protection—Provide flexible low-impedance bus differential protection for various busbar topologies and sizes. Protect systems with up to 21 three-phase bus terminals by using three relays to provide 6 three-phase differential bus zones and 3 independent check zones. Patented open CT detection algorithms block potential misoperations due to open or shorted CT conditions.

Integrated Overcurrent Protection—Choose from ten overcurrent curves for each current input for additional protection. Each torque-controlled time-overcurrent element has two reset characteristics. There is also one level of instantaneous and definite-time elements available for each current input.

Voltage Elements—Supervise current differential tripping within the relay by using voltage elements. Three separate voltage elements consist of two levels of phase under- and overvoltage elements and two levels of negative- and zero-sequence overvoltage elements for each of the three analog voltage quantities measured.

10:1 CT Ratio Mismatch—Install the SEL-487B in a system with nondedicated CTs, with CT ratio mismatches up to 10:1. This allows the same CTs to be used in other protection applications, such as metering or backup relaying.

Dynamic Zone Configuration—Automatically reassign current inputs to different bus zones without using auxiliary relays. Implement the SEL-487B in bus topologies that include bus-tie breakers and disconnects.

Breaker Failure Detection—Mitigate circuit breaker failure with the SEL-487B Relay’s integrated circuit breaker failure detection and logic, which includes retrip capability for each terminal.

Integration and Automation—Select from an array of communications features and protocols to integrate the SEL-487B into your existing communications schemes. The relay features EIA-232 as well as optional copper or fiber Ethernet ports to fit into an array of applications. Protocol options include Mirrored Bits communications, DNP3 LAN/WAN, Modbus, the Simple Network Time Protocol (SNTP), the Parallel Redundancy Protocol (PRP), the IEEE 1588 Precision Time Protocol Version 2 (PTPv2), and IEC 61850 Edition 2.

TiDL Technology—Modernize your substation by applying the TiDL-enabled SEL-487B with the SEL-2240 Axion TiDL nodes. In a TiDL system, the Axion node provides remote I/O and digitizes analog signals over fiber optics for the relay. This simple and secure digital secondary system solution is easy to implement, with no external time source or network engineering required. Replacing copper with fiber increases safety, reduces costs associated with using copper, improves reliability, and limits the impact of an electromagnetic pulse.