10.12
SEL-587Z Instruction Manual
Date Code 20020903
Testing and Troubleshooting
Acceptance Testing
NOTE:
If the electromechanical
induction-disk reset emulation is
enabled (i.e., 51ARS = Y), the element
under test may take some time to
reset fully. If the element is not fully
reset when you run a second test, the
time to trip will be lower than
expected. Usually this setting is set
51ARS = N.
I
Phase
Overcurrent
Elements
The SEL-587Z has many phase overcurrent elements as shown in
. Two kinds of elements are available: elements
that operate based on a comparison between the maximum phase current
directly applied to the phase inputs and the phase overcurrent setting (50/51P)
and those operating on the specific phase current setting (50/51A, 50/51B, and
50/51C).
Test the instantaneous and inverse-time phase overcurrent elements by
applying current to the inputs and comparing relay operation to the phase
overcurrent settings. These tests were outlined previously in this section.
Negative-
Sequence Over-
current Elements
The SEL-587Z has three negative-sequence overcurrent elements as shown in
and
. They all operate based on a
comparison between a negative-sequence calculation of the three-phase inputs
and the negative-sequence overcurrent setting. The negative-sequence
calculation that is performed on the three-phase inputs is as follows (assuming
ABC rotation):
Table 10.3
Inverse-Time Overcurrent Elements
and Corresponding Settings/Relay Word Bits/TAR Commands
Element/Settings
Setting Names
Relay Word Bit
TAR
Maximum Phase
Pickup
Curve
Time Dial
Electromechanical Reset
51PP
51PC
51PTD
51PRS
51P (picked up)
51PT (timed out)
1
1
Phase A
Pickup
Curve
Time Dial
Electromechanical Reset
51AP
51AC
51ATD
51ARS
51A (picked up)
51AT (timed out)
1
1
Phase B
Pickup
Curve
Time Dial
Electromechanical Reset
51BP
51BC
51BTD
51BRS
51B (picked up)
51BT (timed out)
1
1
Phase C
Pickup
Curve
Time Dial
Electromechanical Reset
51CP
51CC
51CTD
51CRS
51C (picked up)
51CT (timed out)
2
2
Residual Ground
Pickup
Curve
Time Dial
Electromechanical Reset
51GP
51GC
51GTD
51GRS
51G (picked up)
51GT (timed out)
2
2
Negative-Sequence
Pickup
Curve
Time Dial
Electromechanical Reset
51QP
51QC
51QTD
51QRS
51Q (picked up)
51QT (timed out)
2
3
Summary of Contents for SEL-587Z
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