Schweitzer Engineering Laboratories, Inc.
SEL-487B Data Sheet
3
Protection Features
Order the 9U chassis version of the SEL-487B to equip
the relay with a maximum of four interface boards. With
four interface boards, the relay has a total of 103 inputs
(72 common inputs and 31 independent inputs) and
40 outputs (24 high-speed, high-current interrupting out-
puts and 16 standard outputs).
Order the 7U chassis version of the SEL-487B to equip
the relay with a maximum of two interface boards. With
two interface boards, the relay has a total of 55 inputs
(36 common inputs and 19 independent inputs) and
24 outputs (12 high-speed, high-current interrupting
outputs and 12 standard outputs).
The 7U and 9U chassis options for the SEL-487B both
contain 21 current inputs and three voltage inputs.
With the flexibility of the expanded SEL
OGIC
control
equations, you need no external auxiliary relays to
configure the relay for complex busbar arrangements.
The SEL-487B provides station-wide protection through
the use of up to six zones of differential protection,
advanced zone selection algorithms, and per-terminal
breaker failure and overcurrent protection.
Dynamic Zone Configuration
The SEL-487B dynamically assigns the input currents to
the correct differential elements without the need for
auxiliary relays. Connect the digital inputs from the bus-
bar disconnect auxiliary contacts directly to the relay.
SEL
OGIC
control equations and zone selection logic will
correctly assign the currents to the differential elements,
even for complex bus arrangements such as the one in
Figure 2.
Busbar configuration information, as a function of the
disconnect status, is readily available. Figure 3 depicts
the response of the relay to the ZONE command,
showing the terminals and bus-zones assigned to each
protection zone.
Figure 2
Bus-Zone Protection Based on Disconnect Switch Positions
52
52
52
52
Silicon
Zone 1
Zone 2
Zone 4
Zone 3
Helium
52
Argon
52
Lithium
Krypton
52
Sodium
Neon
North
52
Boron
East
West
South
DS1
DS2
DS3
