ABB REQ650 Applications Manual page 209

1MRK 505 383-UEN A
Breaker protection REQ650 2.2 IEC
Application manual
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 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.
REFPDIF
I3PW1CT1
I3PW2CT1
I3P
IEC09000619_3_en.vsd
IEC09000619 V3 EN-US
Figure 78: REFPDIF 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
IEC09000620_3_en.vsd
IEC09000620 V3 EN-US
Figure 79: REFPDIF function inputs for normal transformer application
REFPDIF
I3PW1CT1
I3PW2CT1
I3P
Section 10
Logic
203