Schweitzer Engineering Laboratories SEL-421-4 - Figure 5.73 Zone Timers; Instantaneous Line Overcurrent Elements

5.93
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Instantaneous Line Overcurrent Elements
Instantaneous Line Overcurrent Elements
The SEL-421 calculates instantaneous overcurrent elements for phase (P), resid-
ual ground (G, vector sum of I
A
, I
B
, and I
C
), and negative-sequence (Q) quanti-
ties. Four levels of instantaneous elements are available named 50P1–50P4,
50Q1–50Q4, and 50G1–50G4, as shown in Table 5.58 through Table 5 .60, with
settings shown in Table 5.55 through Table 5.57.
These overcurrent elements always operate on the line current (IW terminal cur-
rent or the sum of the IW and IX terminal currents) according to the global set-
ting LINEI (Line Current Source). The instantaneous overcurrent elements are
inputs to the instantaneous directional (67Pn, 67Qn, 67Gn, where n = 1–4) and
definite-time directional overcurrent elements (67PnT, 67QnT, 67GnT, where
n = 1–4). See Directionality on page 5.46 for details on the directional control
option. Note that the 67Pn and 67PnT elements are not directionally controlled
by the built-in logic; they can be made directional through the use of torque con-
trol settings 67P1TC–67P4TC.
Figure 5.73 Zone Timers
Relay
Word
Bits
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Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
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Word
Bits
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Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Z1D
Z1T
Z1PT
Z1GT
Z1P
Z1G
Suspend Timing
Zone 1 Delay Timer Logic
0
CYC
Z1PD
0
CYC
Z1GD
0
CYC
Z2D
Z2T
Z2PT
Z2GT
Z2P
Z2G
Suspend Timing
Zone 2 Delay Timer Logic
0
CYC
Z2PD
0
CYC
Z2GD
0
CYC
Z3D
Z3T
Z3PT
Z3GT
Z3P
Z3G
Suspend Timing
Zone 3 Delay Timer Logic
0
CYC
Z3PD
0
CYC
Z3GD
0
CYC
Z4D
Z4T
Z4PT
Z4GT
Z4P
Z4G
Suspend Timing
Zone 4 Delay Timer Logic
0
CYC
Z4PD
0
CYC
Z4GD
0
CYC
Z5D
Z5T
Z5PT
Z5GT
Z5P
Z5G
Suspend Timing
Zone 5 Delay Timer Logic
0
CYC
Z5PD
0
CYC
Z5GD
0
CYC