ABB Relion 670 Series Applications Manual page 367

1MRK 511 358-UUS A
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
is given, a timer ( set by setting
idea is then that this timer shall have a setting that covers, with some margin, a normal tap
changer operation.
Usually the tap changer mechanism can give a signal, "Tap change in progress", during the time
that it is carrying through an operation. This signal from the tap changer mechanism can be
connected via a BIM module to TCMYLTC (84) or TCLYLTC (84) input TCINPROG, and it can then be
used by TCMYLTC (84) or TCLYLTC (84) function in three ways, which is explained below with the
help of figure 174.
Application manual
tPulseDur . When an VRAISE/VLOWER command
tTCTimeout ) (settable in PST/local HMI) is also started, and the
Section 13
Control
SEMOD159053-337 v1
SEMOD159053-339 v2
SEMOD159053-344 v5
361