Transient/Intermittent Earth-Fault Protection Intrptef - ABB REF615 Applications Manual

Section 5
Protection functions
5.2.3
5.2.3.1
154
core balance current transformers should have a transformation ratio of at least 70:1.
Lower transformation ratios such as 50:1 or 50:5 are not recommended.
Attention should be paid to make sure the measuring transformers are connected
correctly so that DEFxPDEF is able to detect the fault current direction without
failure. As directional earth fault uses residual current and residual voltage (-U
poles of the measuring transformers must match each other and also the fault current
direction. Also the earthing of the cable sheath must be taken into notice when using
core balance current transformers. The following figure describes how measuring
transformers can be connected to the IED.
A070697 V2 EN
Figure 75: Connection of measuring transformers

Transient/intermittent earth-fault protection INTRPTEF

Identification
Table 65: Function identification
IEC 61850 identification:
IEC 60617 identification:
ANSI/IEEE C37.2 device number:
INTRPTEF
I0> ->IEF
67NIEF
1MRS756378 D
), the
0
REF615
Application Manual