occurs in one of the steps in the command sequence, the sequence is terminated. The last error
(L_CAUSE) can be read from the function block and used for example at commissioning.
There is no relation between the command direction and the actual position. For
example, if the switch is in close position it is possible to execute a close
command.
Before an execution command, an evaluation of the position is done. If the parameter
PosDependent is true and the position is in intermediate state or in bad state no execution
command is sent. If the parameter is false the execution command is sent independent of the
position value.
Evaluation of position
M13484-14 v4
The position output from the switches (SXCBR or SXSWI) is connected to the switch controller
SCSWI. The XPOS1, XPOS2 and XPOS3 input signals receive the position, time stamps and quality
attributes of the position which is used for further evaluation.
In the case when there are three one-phase switches connected to the switch control function, the
switch control will "merge" the position of the three switches to the resulting three-phase
position. In the case when the position differ between the one-phase switches, following
principles will be applied:
All switches in open position:
switch control position = open
All switches in close position:
switch control position = close
One switch =open, two switches= close (or
inversely):
switch control position = intermediate
Any switch in intermediate position:
switch control position = intermediate
Any switch in bad state:
switch control position = bad state
The time stamp of the output three-phase position from switch control will have the time stamp
of the last changed phase when it reaches the end position. When it goes to intermediate position
or bad state, it will get the time stamp of the first changed phase.
In addition, there is also the possibility that one of the one-phase switches will change position at
any time due to a trip. Such situation is here called pole discrepancy and is supervised by this
function. In case of a pole discrepancy situation, that is, the positions of the one-phase switches
are not equal positions for a time longer than the setting
tPoleDiscord, an error signal POLEDISC
will be set.
In the supervision phase, the switch controller function evaluates the "cause" values from the
switch modules Circuit breaker (SXCBR)/ Circuit switch (SXSWI). At error the "cause" value with
highest priority is shown.
Blocking principles
M13484-37 v5
The blocking signals are normally coming from the bay control function (QCBAY) and via the IEC
61850 communication from the operator place.
The different blocking possibilities are:
1MRK 502 066-UUS B
Section 14
Control
841
Technical manual
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