Application - ABB RELION 670 Series Applications Manual

1MRK 511 364-UUS A
15.7.2

Application

The Fixed signals function FXDSIGN generates nine pre-set (fixed) signals that can be used in the
configuration of an IED, either for forcing the unused inputs in other function blocks to a certain
level/value, or for creating certain logic. Boolean, integer, floating point, string types of signals are
available.
One FXDSIGN function block is included in all IEDs.
Example for use of GRP_OFF signal in FXDSIGN
The Restricted earth fault function REFPDIF (87N) can be used both for auto-transformers and
normal transformers.
When used for auto-transformers, information from both windings parts, together with the
neutral point current, needs to be available to the function. This means that three inputs are
needed.
ANSI11000083 V1 EN-US
Figure 79: REFPDIF (87N) function inputs for autotransformer application
For normal transformers only one winding and the neutral point is available. This means that only
two inputs are used. Since all group connections are mandatory to be connected, the third input
needs to be connected to something, which is the GRP_OFF signal in FXDSIGN function block.
FXDSIGN
GRP_OFF
ANSI11000084 V1 EN-US
Figure 80: REFPDIF (87N) function inputs for normal transformer application
Application manual
REFPDIF (87N)
I3PW1CT1
I3PW2CT1
I3P
ANSI11000083_1_en.vsd
REFPDIF (87N)
I3PW1CT1
I3PW2CT1
I3P
ANSI11000084_1_en.vsd
Section 15
Logic
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