3-22
Communications
Date Code 970103
SEL-251, -2, -3 Instruction Manual
specific setting by entering the setting name as parameter p. If p is a SEL
OGIC
TM
Control
Equations element, you do not need to include the parenthetical [e.g., just K, not K(1234)]. If
you do not specify a setting, the procedure initiates at the first setting, Relay ID.
The relay prompts you for each group setting and checks the new setting against established
limits. If a setting falls within its setting range, the relay prompts you for the next group setting.
If a setting is outside its established limits, an "Out of range" or "Invalid" error message results.
You have another chance to enter the setting. If you want to retain the old setting, press
<
ENTER
> and proceed to the next group setting.
The logic variable expressions should contain the name of each Relay Word bit (e.g.,
51P
) and
the correct delimiter "+" for OR logic, "*" for AND logic, and "," for the ETC(1) and ITC(1)
torque control logic variables. Enter the logic expression with no spaces between the Relay
Word bits and the delimiters. Some examples:
A(12) =
51P
+
51QP
+
51NP
OR logic variable A takes bits from Relay Word rows 1 and
2 and uses the + delimiter.
V(56) =
A
*
F
*
KT
AND logic variable V takes bits from Relay Word rows 5
and 6 and uses the * delimiter.
ITC(1) =
50L
,
50H
The
50L
and
50H
phase overcurrent elements from Relay
Word row 1 are selected for internal torque control. The
respective time delayed elements they control (
50LT
and
50HT
) are also internally torque controlled through this
setting.
Note that AND logic variables
V
,
W
,
X
,
Y
, and
ZT
cannot select other AND variables from
Relay Word rows 5 and 6. They can only select the OR logic variables
A
,
B
,
C
,
D
,
E
,
F
,
H
,
J
,
KT
, and
!L
from Relay Word rows 5 and 6. This prevents recursive logic such as:
V(56) =
V
*
W
(this setting is not possible)
If no function is desired for a logic variable, type
NA <ENTER>
.
To fully utilize the relay's resources, self-tests are delayed when any of the following elements
are picked up:
51P, 50H, 51QP, 50Q, 51NP, 50NL, 50NH
51T, 51QT, 50QT, 51NT, and 50NLT.
Therefore, you should be careful to set the relay so that under normal conditions none of these
elements are picked up.
When you finish entering setting changes, you need not scroll through the remaining settings.
Type
END <ENTER>
after your last change to display the new settings and enable prompt. Do
not use the END statement at the Relay ID setting; use
<CTRL>X
to abort the SET procedure
from this point.
After you enter all data, the relay displays new group and global settings and prompts for
approval to enable new group settings. Answer
Y <ENTER>
to approve the new settings; the
relay enables them and clears the event buffer. If the active group is the same as the one you are
setting, the ALARM output pulses closed.
