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.
I3PW1CT1
I3PW2CT1
I3P
REFPDIF (87N)
ANSI11000083_1_en.vsd
ANSI11000083 V1 EN
Figure 303: 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.
I3PW1CT1
I3PW2CT1
I3P
REFPDIF (87N)
ANSI11000084_1_en.vsd
GRP_OFF
FXDSIGN
ANSI11000084 V1 EN
Figure 304: REFPDIF (87N) function inputs for normal transformer application
1MRK504116-UUS C Section 3
IED application
745
Application manual
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