Siemens 6MD86 - Page 444

Parameter: Number of tap positions
•
Default setting Number of tap positions = 15
With the Number of tap positions parameter, you set the number of transformer taps. The range of
values extends from 2 to 127. The output of the tap position is limited from -63 to +63. If the number of taps
is > 63, set the Tap-display offset parameter so that the output of the tap position is within the range of
-63 to +63.
Parameter: Tap-coding type
•
Default setting Tap-coding type = binary
In the Tap-coding type list box, select the interpretation type of the indication pending at the binary input.
You can select from the following options:
•
binary
•
1-of-n
•
BCD
•
table
•
BCD signed
•
gray
A selection of tap-coding types is described in greater detail using examples in the following text.
Routing of the Binary Inputs (Tap-Coding Type binary)
The following table shows the routing of 3 binary inputs (BI 1 to BI 3) with 4 transformer tap positions desig-
nated 3 to 6. BI4 is the moving contact. The encoding is in binary.
Table 6-25 Routing of the Binary Inputs (Tap-Coding Type binary)
Example
BI1 BI2 BI3 BI4 BI5 BI6
Tap changer X X X X
Meaning Bit 1 Bit 2 Bit 3 Moving
contact
Tap = 1 1 0 0
With 3 binary inputs, a maximum of 2
3
-1 = 7 tap positions can be mapped in binary code. If all routed binary
inputs indicate 0, this is interpreted as a connection error and is reported by Position --- or -64 with quality
invalid. The representation of transformer taps should start with the metered value 3. You must configure the
information properties as follows for the example:
Tap-coding type: binary
Number of tap positions: 7
Number of bits f. tap code: 4
Tap-display offset: 2
Moving contact (highest binary input): Yes
The 3 binary inputs must be numbered sequentially, for example, BI 1, BI 2, BI 3, and BI 4 for the moving
contact.
Routing of the Binary Inputs (Tap-Coding Type BCD)
The following table shows the routing of 6 binary inputs (BI 1 to BI 6) with 39 transformer tap positions desig-
nated 1 to 39. The encoding is in BCD. BI 7 is the moving contact.
Control Functions
6.8 Transformer Tap Changers
444 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017