19
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, which can be located anywhere between the lowest
and highest taps as long as they are grouped together in one section. 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 2.6 Bi-polar Mode Analog Output
Programming Example:
A typical transformer Load Tap Changer application with 16 raised and 16 lowered
taps, 3 neutral taps located at 0, with 10
o
per tap, presently set on tap “2L” would be
programmed as follows:
OP 2 Operating mode = 21 OP 21 Degrees per tap = 10.000 OP 27 Present tap = -2
OP 20 Number of taps = 35
OP 22 Number of neutrals = 3
OP 28 Load present tap
OP 23 Neutral start tap = 0