3.10
SEL-587Z Instruction Manual
Date Code 20020903
Relay Elements
Overcurrent Protection
Overcurrent Protection
The SEL-587Z includes a set of nondirectional overcurrent elements to
complement the differential protection. All overcurrent elements have
independent pickup and time-delay settings. If necessary, you can externally
torque control the inverse-time overcurrent elements using a setting or a
control input.
The overcurrent elements measure the fundamental frequency value only, all
harmonics are removed. If the CTs are wye connected, the relay can provide
phase, negative-sequence, and residual overcurrent elements for that channel.
If the CTs are delta connected, the relay provides only phase and negative-
sequence overcurrent elements. In new installations, use wye-connected CTs
whenever possible to maximize available protection and simplify overcurrent
relay settings.
Overcurrent
Elements
summarize the overcurrent elements provided by the
SEL-587Z. “Max” elements respond to the maximum value in any of the three
phases. “Phase” elements measure each phase separately (a measuring
element per phase).
Instantaneous Overcurrent Element Maximum
shows the logic for the three-phase maximum
overcurrent elements. The output is the assertion of the phase with the highest
current value. The elements are not torque controlled.
Table 3.2
Instantaneous Overcurrent Elements
Element Description
Instantaneous Elements
Settings
Phase (IA, IB, and IC)
50P1, 50P2, 50P3 (max)
50A1, 50B1, 50C1 (phase)
50A2, 50B2, 50C2 (phase)
50P1P, 50P2P, 50P3P
50A1P, 50B1P, 50C1P
50A2P, 50B2P, 50C2P
Negative Sequence (3I2)
50Q1, 50Q2
50Q1P, 50Q2P
Residual (IG = IA + IB + IC)
50G1, 50G2
50G1P, 50G2P
Table 3.3
Inverse-Time Overcurrent Elements
Label
Inverse-Time
Elements
Settings
Torque
Control
Phase (IA, IB, and IC)
51P (max)
51A (phase)
51B (phase)
51C (phase)
51PP, 51PC, 51PTD, 51PRS
51AP, 51AC, 51ATD, 51ARS
51BP, 51BC, 51BTD, 51BRS
51CP, 51CC, 51CTD, 51CRS
51PTC
51ATC
51BTC
51CTC
Negative Sequence (3I2)
51Q
51QP, 51QC, 51QTD, 51QRS
51QTC
Residual
(IG = IA + IB + IC)
51G
51GP, 51GC, 51GTD, 51GRS
51GTC
Содержание SEL-587Z
Страница 10: ...This page intentionally left blank ...
Страница 12: ...This page intentionally left blank ...
Страница 66: ...This page intentionally left blank ...
Страница 106: ...This page intentionally left blank ...
Страница 126: ...This page intentionally left blank ...
Страница 162: ...This page intentionally left blank ...
Страница 228: ...This page intentionally left blank ...
Страница 260: ...This page intentionally left blank ...
Страница 276: ...This page intentionally left blank ...