Pulse Control - ABB RELION REX640 Technical Manual

1MRS759142 C
9.10.5.8
REX640
Technical Manual
GUID-A68D2C7E-9185-4654-9BD6-331BA7948A8B V1 EN
Figure 816: Inverse time characteristic for different values of T1 or T2 (The
smaller figure is a zoom-in of the larger one)

Pulse control

The tap changer generates an active operating signal when the tap-changing process
is active. This signal is used for alarming purposes and must be connected to the TCO
input. If the signal is active (=TRUE) for more than 15 seconds after the control pulse
has been deactivated, an alarm is generated
input is not connected, no alarm is generated.
The control operation is disabled when the TCO input signal is active, unless no stuck
tap changer is detected (Alarm indication
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.
To be more certain that no new pulses are sent when the tap changer is in operation,
the tap changer operating signal can be connected to the LTC_BLOCK input. In this
case, external blocking is achieved when an automatic pulse is sent to the operating tap
Control functions
(Alarm indication chapter). If the TCO
chapter). Thus, the controller cannot send
Section 9
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