37
Modes 20 & 21: Bi-polar Segmented
These modes are used for LTC monitoring when the
neutral tap(s) are in the center of the dial and there is an equal number of raised and lowered
taps. There may be multiple neutral taps, but they can only be located at tap
0
. Mode 20 has
a linear analog output that continuously varies with LTC shaft position. Mode 21 has a
stepped analog output that jumps with each tap change. To select this operating mode use the
OP 2, Func, MODE
command to change the value to
“20”
or
“21”
.
Figure 2.5 Bi-polar Mode Analog Output
Programming Example:
A typical transformer Load Tap Changer application with 16 raised and 16 lowered
taps, 3 neutral taps, with 10
o
per tap, presently set on tap “2L” would be programmed as
follows:
OP 2 Operating mode = 21
OP 20 Number of taps = 35
OP 21 Degrees per tap = 10.000
OP 22 Number of neutrals = 3
OP 27 Present tap = -2
OP 28 Load present tap