SEL-487E-3, -4 Data Sheet Schweitzer Engineering Laboratories, Inc.
8
over- and undervoltage, and frequency elements, along
with V/Hz elements provide the SEL-487E with accurate
transformer protection for off-frequency events and over-
excitation conditions.
Use the SEL-487E for complete protection of generator
step-up (GSU) transformer applications. Use built-in ther-
mal elements for monitoring both generator and transformer
winding temperatures. Apply the V/Hz element with two
level settings for overexcitation protection of loaded and
unloaded generator operating conditions. Set the directional
power elements to detect forward and reverse power flow
conditions for monitoring and protection of the GSU
transformer in prime power, standby, base load, and peak
shaving applications. Figure 7 shows the SEL-487E in a
typical GSU application.
Distance Protection
The SEL-487E simultaneously supports as many as four
zones of phase and ground distance protection by using
mho or quadrilateral characteristics. You can use expanded
SEL
OGIC control equations to tailor the relay further to
your particular application. The SEL-487E distance ele-
ments are flexible enough to be used for transmission
line or transformer winding protection, as shown in Figure 8
and Figure 9.
Six Terminal Feeder Protection
Use the six three-phase current terminals on the SEL-487E
to provide comprehensive feeder protection and control
including overcurrent, directional overcurrent, reclosing,
and breaker failure protection for six feeders. Figure 10
shows a single SEL-487E can provide full feeder func-
tionality of six single function feeder relays thereby
reducing the device count within the system.
Figure 6 Single Transformer REF Application
Figure 7 Generator Step-Up Application
High Voltage
Low Voltage
Tertiary
REF
REF
3
3
3 31133
3
3
3 33
1
1
REF REF
Figure 8 Transformer Distance Application
Figure 9 Transmission Line Distance Application
Figure 10 Six Terminal Feeder Application
5252
S
3
3
Zone 1
Zone 2
T
3
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