Schweitzer Engineering Laboratories SEL-311C - All SEL OGIC Control Equations Must be Set; Figure H.2 Result of Falling Edge Operator on a Deasserting Out-Of-Step Blocking Element

H.8
SEL-311C Relay Instruction Manual Date Code 20060320
Setting SELOGIC Control Equations
SEL
OGIC Control Equations
This allows recovery from a power swing condition to be observed.
Figure H.2 demonstrates the action of the falling edge operator \ on the out-of-
step blocking element in setting ER.
Figure H.2 Result of Falling Edge Operator on a Deasserting
Out-of-Step Blocking Element
All SELOGIC Control
Equations Must Be
Set
All SELOGIC control equations must be set one of the following ways (they
cannot be “blank”):
➤ single Relay Word bit (e.g., 52A = IN101)
➤ combination of Relay Word bits (e.g., TR = 51PT + 51GT +
50P1 * SH0)
➤ directly to logical 1 (e.g., 67P1TC = 1)
➤ directly to logical 0 (e.g., TRCOMM = 0)
Set SELOGIC Control Equations Directly to 1 or 0
SELOGIC control equations can be set directly to:
➤ 1 (logical 1) or
➤ 0 (logical 0)
instead of with Relay Word bits. If a SEL
OGIC control equation setting is set
directly to 1, it is always “asserted/on/enabled.” If a SEL
OGIC control equation
setting is set equal to 0, it is always “deasserted/off/disabled.”
Under the SHO Command (Show/View Settings) on page 10.25, note that a
number of the factory SEL
OGIC control equation settings are set directly to 1
or 0.
The individual SEL
OGIC control equation settings explanations (referenced in
SEL
OGIC Control Equation Settings (Serial Port Command SET L) on
page SET.16 discuss whether it makes logical sense to set the given SEL
OGIC
control equation setting to 0 or 1 for certain criteria.
Set SELOGIC Control Equations Directly to 1 or 0—Example
Of special concern are the SELOGIC control equation torque control settings
67P1TC through 51QTC for the overcurrent elements. In the factory settings
included in a standard shipment of an SEL-311C, these are all set directly to
logical 1. See these factory settings in SHO Command (Show/View Settings).
If one of these torque control settings is set directly to logical 1
e.g.,
67QTC = 1 (set directly to logical 1)
then the corresponding overcurrent element is subject only to the directional
control. See Figure 3.23 for negative-sequence overcurrent element 67QTC
logic.
One Processing Interval
\OSB
OSB
NOTE: SELOGIC control equation
torque control settings (e.g., 67P1TC,
51P1TC) cannot be set directly to
logical 0.