T
T1 or T2
The monitored data UD_CTL shows the differential voltage value U
m
– U
p
. If the
value exceeds half of the
Band width voltage setting and has a negative sign, a
raising pulse is issued. The UD_CTL monitored data can also be seen in the DT timer
mode.
The hysteresis approach is presented in
Figure 563: Inverse time characteristic for different values on T1 or T2 (The smaller
figure is a zoom-in of the larger one)
9.5.4.8
Pulse control
The tap changer generates an active operating signal when the tap-changing
process is active. This signal is to be connected to the
TCO
input. The signal is used
for alarming purposes. If the signal is active (=TRUE) for more than 15 seconds after
the control pulse has been deactivated, an alarm is generated (
TCO
input is not connected, no alarm is generated.
The control operation is disabled when the
TCO
input signal is active, unless no tap
Chapter 9.5.4.10 Alarm indication
). Thus, the controller
cannot send new pulses to the tap changer when this is already operating because
tap changers are typically immune to new pulses when they operate. Furthermore,
because the pulses are omitted, the tap changer pulse counter of the controller is
not incremented.
The commands are not tolerated during an active pulse. Therefore the command
pulse length (setting
LTC pulse time) has to be carefully selected, although an
active
TCO
input is used internally to prevent new commands from reaching the tap
changer.
1MRS757644 H
Control functions
620 series
Technical Manual
1061
