Ct Earthing Direction; Setting Guidelines; Setting And Configuration - ABB RELION 650 Series Applications Manual

1MRK 505 363-UEN A
REFPDIF
IdN/I
IEC09000112-4 V2 EN-US
Figure 30: Connection of restricted earth-fault, low impedance function REFPDIF for a
6.1.2.5

CT earthing direction

To make the restricted earth-fault protection REFPDIF operate correctly, the main CTs are
always supposed to be star -connected. The main CT's neutral (star) formation can be
positioned in either way,
reference directions towards the protected transformers, as shown in Figure "". Thus the IED
always measures the primary currents on all sides and in the neutral of the power transformer
with the same reference direction towards the power transformer windings.
The earthing can be freely selected for each of the involved current transformers.
6.1.3

Setting guidelines

6.1.3.1

Setting and configuration

Recommendation for analog inputs
I3P: Neutral point current ( All analog inputs connected as 3Ph groups in ACT).
I3PW1CT1: Phase currents for winding 1 first current transformer set.
I3PW1CT2: Phase currents for winding1 second current transformer set for multi-breaker
arrangements. When not required configure input to "GRP-OFF".
Application manual
I3PW1CT1
I3P
solidly earthed reactor
ToObject or FromObject . However, internally REFPDIF always uses
Reactor
IEC09000112-4.vsd
Section 6
Differential protection
M13048-29 v12
IP14942-1 v1
M13052-3 v3
M13052-8 v9
71