Schweitzer Engineering SEL-387-0, Instruction Manual

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1.4
SEL-387-0, -5, -6 Relay Instruction Manual Date Code 20170601
Introduction and Specifications
Application Ideas
Through-Fault Event
Monitor (SEL-387-5
and SEL-387-6)
Through faults are a major cause of transformer damage and failure. Fault
currents cause cumulative mechanical damage by displacing transformer
windings every time a fault occurs. Thermal stress from fault currents
damages insulation. The SEL-387-5 and the SEL-387-6 provide a through-
fault event monitor to gather fault current level, duration, and date/time for
each through fault. The monitor performs a simple I
2
t calculation and
cumulatively stores calculation results for each phase. Use these through-fault
event data to schedule proactive maintenance for transformers and to help
justify possible system enhancements to mitigate through faults.
Programmable
Optoisolated Inputs
and Output Contacts
The SEL-387 is equipped with enhanced SEL
OGIC®
control equations that
allow you to design a custom tripping or control scheme. SEL
OGIC
control
equation functions include independent timers, tripping, event report
triggering, and relay output contact control.
Application Ideas
Figure 1.2 Transformer and Overcurrent Protection
3
3
3
3
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51
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Combined
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Q 51
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Q 51
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G
Q
50
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Q 51
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50
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Q 51
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Q
51
P
G
∑
Combined