Tap changer extreme positions
SEMOD159053-339 v2
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 ULOWER/URAISE command is prevented in both automatic and manual mode.
Monitoring of tap changer operation
SEMOD159053-344 v5
The Tap changer control and supervision, 6 binary inputs TCMYLTC or 32 binary inputs
TCLYLTC output signal URAISE or ULOWER is set high when TR1ATCC or TR8ATCC function has
reached a decision to operate the tap changer. These outputs from TCMYLTC and TCLYLTC
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 or TCLYLTC setting parameter
tPulseDur
. When an URAISE/ULOWER 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.
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 or TCLYLTC input TCINPROG, and it can then be
used by TCMYLTC or TCLYLTC function in three ways, which is explained below with the help
of figure
161.
URAISE/ULOWER
tTCTimeout
TCINPROG
a
h
d
e f
g
cb
IEC06000482_2_en.vsd
IEC06000482 V2 EN-US
Figure 161: Timing of pulses for tap changer operation monitoring
pos Description
a Safety margin to avoid that TCINPROG is not set high without the simultaneous presence of an URAISE
or ULOWER command.
b Time setting
tPulseDur
.
c Fixed extension 4 sec. of
tPulseDur
, made internally in TCMYLTC or TCLYLTC function.
d Time setting
tStable
e New tap position reached, making the signal “tap change in progress” disappear from the tap changer,
and a new position reported.
f The new tap position available in TCMYLTC or TCLYLTC.
g Fixed extension 2 sec. of TCINPROG, made internally in TCMYLTC or TCLYLTC function.
h Safety margin to avoid that TCINPROG extends beyond
tTCTimeout
.
The first use is to reset the Automatic voltage control for tap changer function TR1ATCC for
single control and TR8ATCC for parallel control as soon as the signal TCINPROG disappears. If
the TCINPROG signal is not fed back from the tap changer mechanism, TR1ATCC or TR8ATCC
will not reset until
tTCTimeout
has timed out. The advantage with monitoring the TCINPROG
Section 13 1MRK 511 358-UEN A
Control
322
Application manual
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