3-6 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements Date Code 20001006
SEL-351 Instruction Manual
67P1TC = IN5 Input IN5 deasserted (67P1TC = IN5 = logical 0):
Then phase instantaneous/definite-time overcurrent elements 67P1/67P1T
are defeated and nonoperational, regardless of any other setting.
Input IN5 asserted (67P1TC = IN5 = logical 1):
Then only the corresponding directional control input from Figure 4.18 has
to be considered in the control of phase instantaneous/definite-time over-
current elements 67P1/67P1T.
If directional control enable setting E32 =N, then phase instantaneous
/definite-time overcurrent elements 67P1/67P1T are enabled and
nondirectional.
Sometimes SELOGIC Control Equation torque control settings are set to provide directional control.
See Directional Control Provided by Torque Control Settings at the end of Section 4: Loss-of-
Potential, Load Encroachment, and Directional Element Logic.
Combined Single-Phase Instantaneous Overcurrent Elements
The single-phase instantaneous overcurrent element Relay Word bit outputs in Figure 3.1 are
combined together in Figure 3.4 on a per phase basis, producing Relay Word bit outputs 50A,
50B, and 50C.
Relay Word bits 50A, 50B, and 50C can be used to indicate the presence or absence of current in a
particular phase.
Figure 3.4: Combined Single-Phase Instantaneous Overcurrent Elements
Courtesy of NationalSwitchgear.com
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