Schweitzer Engineering SEL-387-0, Instruction Manual

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Date _______________
Date Code 20170601 Instruction Manual SEL-387-0, -5, -6 Relay
SET.3 of 4
Connection Check
Connection Check
System load conditions should be higher than 0.1 A secondary. 0.5 A secondary is recommended for the best
results.
Mismatch Calculation:
Magnitude, Angle, and Phase Rotation Check
Issue MET SEC <Enter> to the serial port or front panel.
1. Calculated relay amperes match MET SEC amperes?
2. Phase rotation is as expected for each winding?
3. Do angular relationships among windings correspond to expected results? (Remember that secondary current
values for load current flowing out of a winding will be 180° out of phase with the reference phase position for that
winding. The reason is that CT polarity marks normally face away from the transformer on all windings.)
Differential Connection (issue MET DIF <Enter> to serial port or front panel)
Operate
Current:
IOP1 = IOP2 = IOP3 =
Restraint
Current:
IRT1 = IRT2 = IRT3 =
Mismatch
Calculation:
MM1 = MM2 = MM3 =
Check individual current magnitudes, phase angles, and operate and restraint currents in an event report if mismatch is not less than
0.10.
Winding 1 Winding 2 Winding 3 Winding 4
A-Phase Secondary
Amperes:
IAW1 = IAW2 = IAW3 = IAW4
A-Phase Angle:
B-Phase Secondary
Amperes:
IBW1 = IBW2 IBW3 IBW4
B-Phase Angle:
C-Phase Secondary
Amperes:
ICW1 = ICW2 = ICW3 = ICW4 =
C-Phase Angle:
MMn
IOPn
IRTn
------------- =
0
–135
±
180
135
–90
–45
45
90
0
–135
±
180
135
–90
–45
45
90
0
–135
±
180
135
–90
–45
45
90
0
–135
±
180
135
–90
–45
45
90
Winding 1 Winding 2 Winding 3 Winding 4