3-16
Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements
Date Code 20001006
SEL-351 Instruction Manual
Figure 3.13: Levels 5 Through 6 Negative-Sequence Instantaneous Overcurrent Elements
T
IME
-O
VERCURRENT
E
LEMENTS
Phase Time-Overcurrent Elements
Four phase time-overcurrent elements are available. The elements are enabled with the E51P
enable setting as follows:
Table 3.1: Available Phase Time-Overcurrent Elements
Time-Overcurrent
Element
Enabled with
Setting
Operating Current
See Figure
51PT
E51P = 1 or 2
I
P
, maximum of A-, B-, and
C-phase currents
Figure 3.14
51AT
E51P = 2
I
A
, A-phase current
Figure 3.15
51BT
E51P = 2
I
B
, B-phase current
Figure 3.16
51CT
E51P = 2
I
C
, C-phase current
Figure 3.17
The following is an example of 51PT element operation. The other phase time-overcurrent
elements operate similarly (note the similarity among the logic in Figure 3.14, Figure 3.15,
Figure 3.16, and Figure 3.17).
Summary of Contents for SEL-351
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