3.4 Primary Commissioning Tests with the Generator
381
7UM62 Manual
C53000-G1176-C149-3
Figure 3-35
Directional Check with Toroidal Residual Current Transformers
Directional Check
with C.T.'s in
Holmgreen
Connection
If the current is supplied from a set of c.t.'s in Holmgreen connection (Figure 3-36), the
displacement voltage is obtained in the same manner as in the above circuit. Only the
current of that current transformer which is in the same phase as the by-passed
voltage transformer in the delta connection is fed into the current path. In case of
active power in generator direction, the same conditions apply for the relay - in
principle - as with an earth fault in generator direction in a compensated network and
vice versa.
Figure 3-36
Directional Check with Current Transformers in Holmgreen Connection
G
7UM62
U
E
I
EE2
e
n
Z
Q7
Q8
R14
R13
l
k
L1
L2
L3
G
7UM62
U
E
I
EE2
R
T
e
n
L1
L2
L3
Q7
Q8
R14
R13
