ABB REC670 Applications Manual page 446

Section 14
Control
440
example, IBLK for over-current blocking. The other TR8ATCCs (90) that receive a
mutual block signal will only set its AUTOBLK output.
The mutual blocking remains until TR8ATCC (90) that dispatched the mutual block
signal is de-blocked. Another way to release the mutual blocking is to force TR8ATCC
(90), which caused mutual blocking to Single mode operation. This is done by
activating the binary input SNGLMODE on TR8ATCC (90) function block or by
setting the parameter OperationPAR to Off from the built-in local HMI or PST.
TR8ATCC (90) function can be forced to single mode at any time. It will then behave
exactly the same way as described in section
transformer", except that horizontal communication messages are still sent and
received, but the received messages are ignored. TR8ATCC (90) is at the same time
also automatically excluded from the parallel group.
Disabling of blockings in special situations
When the Automatic voltage control for tap changer TR1ATCC (90) for single control
and TR8ATCC (90) for parallel control, function block is connected to read back
information (tap position value and tap changer in progress signal) it may sometimes
be difficult to find timing data to be set in TR1ATCC (90) or TR8ATCC (90) for proper
operation. Especially at commissioning of for example, older transformers the sensors
can be worn and the contacts maybe bouncing etc. Before the right timing data is set it
may then happen that TR1ATCC (90) or TR8ATCC (90) becomes totally blocked or
blocked in auto mode because of incorrect settings. In this situation, it is recommended
to temporarily set these types of blockings to alarm instead until the commissioning of
all main items are working as expected.
Tap Changer position measurement and monitoring
Tap changer extreme positions
This feature supervises the extreme positions of the tap changer according to the
settings LowVoltTap and HighVoltTap. When the tap changer reaches its lowest/highest
position, the corresponding VLOWER/VRAISE command is prevented in both
automatic and manual mode.
Monitoring of tap changer operation
The Tap changer control and supervision, 6 binary inputs TCMYLTC (84) or 32 binary
inputs TCLYLTC (84) output signal VRAISE or VLOWER is set high when
TR1ATCC (90) or TR8ATCC (90) function has reached a decision to operate the tap
changer. These outputs from TCMYLTC (84) and TCLYLTC (84) function blocks shall
be connected to a binary output module, BOM in order to give the commands to the tap
changer mechanism. The length of the output pulse can be set via TCMYLTC (84) or
TCLYLTC (84) setting parameter tPulseDur. When an VRAISE/VLOWER command
is given, a timer ( set by setting tTCTimeout ) (settable in PST/local HMI) is also
started, and the idea is then that this timer shall have a setting that covers, with some
margin, a normal tap changer operation.
1MRK 511 401-UUS A
"Automatic voltage control for a single
Bay control REC670 2.2 ANSI
SEMOD159053-329 v4
SEMOD159053-337 v1
SEMOD159053-339 v3
SEMOD159053-344 v5
Application manual