Schweitzer Engineering Laboratories SEL-587Z - Figure 3.11 Instantaneous Overcurrent Maximum Elements; Figure 3.12 Phase Overcurrent Elements

3.11
Date Code 20020903 SEL-587Z Instruction Manual
Relay Elements
Overcurrent Protection
Figure 3.11 Instantaneous Overcurrent Maximum Elements.
Instantaneous Overcurrent Phase
Figure 3.12 shows the logic for the phase overcurrent elements. Each phase
has two elements, comparing the individual phase current values against the
phase settings. The elements are not torque controlled.
Figure 3.12 Phase Overcurrent Elements.
Instantaneous Negative-Sequence and Residual
Figure 3.13 on page 3.12 shows the logic for the negative-sequence and
residual overcurrent elements. Each element has two levels. The elements are
not torque controlled.
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+
_
+
_
+
50P1
50P2
50P3
50P3P
50P2P
50P1P
Max (IA, IB, IC)
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+
_
+
50A1
50A2
50A2P
50A1P
IA
_
+
_
+
50B1
50B2
50B2P
50B1P
IB
_
+
_
+
50C1
50C2
50C2P
50C1P
IC