6
TB MRI(K)3-C 03.02 E
P1
P2
S1
S2
P1
P2
S1
S2
P1
P2
S1
S2
I1
I2
I3
IE
L1.1
B3
B4
L1.2
L2.1
B5
L2.2
B6
L3.1
B7
L3.2
B8
B1
B2
L1
L2
L3
Figure 3.3: Measuring of phase currents and earth current detection
in Holmgreen connection (IE)
This kind of connection can be used where three
phase CTs are available and a combination of phase
and earth current measuring is required.
Figure 3.4: Measuring of earth current with core-type CT (IE)
With the combination of phase and earth current
measuring, CTs to be connected according to Figure
3.3 or Figure 3.4.