Siemens 6MD85, Manual

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[scconnection, 1, en_US]
Figure 5-100 Connecting the Measuring Points with the Capacitor Bank Function Group
There are consistency checks that validate the connections of voltage measuring points to the function group:
•
The connection type must be identical for all measuring points connected to the same interface of the
function group.
•
The rated voltage (primary and secondary) must be identical for all measuring points connected to the
same interface.
•
If more than 1 measuring point is connected to one voltage interface, a function block must be added to
enable the selection of the voltage measuring points.
Application and Setting Notes
CFC Control
The voltage measuring point is selected by logic block chart on basis of the measuring point IDs. If more than
one measuring point is connected to the interface of the function group, instantiate the function block
Voltage measuring-point selection from the library in the corresponding function group.
In order to ensure the correct measuring-point connection for the function group, a logic block chart has to
define the actual valid IDs for the input
>MP-ID selection
of the function block.
The following logic block chart implementation is based on the example given in Figure 5-99 .
If the Disconnector 1 (QB1) is closed and no matter what the position the Disconnector 2 (QB2) is, the value 2
is the output of CFC block mux_d_1 and transferred to the input
>MP-ID selection
. Then, the Meas.point
V-3ph with ID 2 is selected as the reference voltage. Similarly, the Meas.point V-3ph with ID 3 is selected as
the reference voltage if the Disconnector 1 (QB1) is not closed (open or in intermediate position) while
Disconnector 2 (QB2) is closed.
[SclocfcVP, 1, --_--]
Figure 5-101 Logic Block Chart: Voltage Selection Using Measuring Point ID
However, the disconnectors might be both open or in a transient state. In this case, the input IN3 of the block
bool_int_1 becomes true, the value 0 is used as the ID for voltage selection input (
>MP-ID selection
). If
ID 0 is selected, then all voltage values of the respective function-group interface are set to 0 V immediately.
An alarm indication
Selection invalid
is issued and the indication
Health
is issued as
OK
. In case you
want to supply the function group with voltage values under the condition that both disconnectors are open
or in transient state from one or the other busbar, you can alter the CFC chart respectively.
5.9.3
Function-Group Types
5.9 Voltage Measuring-Point Selection
SIPROTEC 5, High-Voltage Bay Controller, Manual 301
C53000-G5040-C015-9, Edition 11.2017