Date Code 20001006 Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements 3-5
SEL-351 Instruction Manual
Directional Control Option
The phase instantaneous overcurrent element Relay Word bit outputs in Figure 3.1 (50P1, 50P2,
50P3, and 50P4) are inputs into the phase instantaneous/definite-time overcurrent element logic in
Figure 3.3.
Levels 1 through 4 in Figure 3.3 have corresponding directional control options. See Figure 4.18
in Section 4: Loss-of-Potential, Load Encroachment, and Directional Element Logic for more
information on this optional directional control. If the directional control enable setting E32 is set:
E32 = N
then directional control is defeated, and the directional control inputs into all four phase instanta-
neous/definite-time overcurrent element levels in Figure 3.3 are asserted to logical 1 continuously.
Then only the corresponding SELOGIC Control Equation torque control settings have to be
considered in the control of the phase instantaneous/definite-time overcurrent elements.
For example, consider the Level 1 phase instantaneous/definite-time overcurrent elements
67P1/67P1T in Figure 3.3. If the directional control enable setting E32 is set:
E32 = N
then the directional control input from Figure 4.18 (Level 1) is asserted to logical 1 continuously.
Then only the corresponding SELOGIC Control Equation torque control setting 61P1TC has to be
considered in the control of the phase instantaneous/definite-time overcurrent elements
67P1/67P1T.
SELOGIC Control Equation torque control settings are discussed next.
Torque Control
Levels 1 through 4 in Figure 3.3 have corresponding SELOGIC Control Equation torque control
settings 67P1TC through 67P4TC. SELOGIC Control Equation torque control settings cannot be
set directly to logical 0. The following are torque control setting examples for Level 1 phase
instantaneous/definite-time overcurrent elements 67P1/67P1T.
67P1TC = 1 Setting 67P1TC set directly to 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.
Note: All overcurrent element SELOGIC Control Equation torque
control settings are set directly to logical 1 (e.g., 67P1TC = 1) for the
factory default settings. See SHO Command (Show/View Settings) in
Section 10: Serial Port Communications and Commands for a list of the
factory default settings.
Courtesy of NationalSwitchgear.com
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