Connecting the measurands the REG-DP
8.1 Connecting the zero sequence voltage
Regulation should based the zero sequence voltage measured the P-coil.
The P-coil's winding generally designed apply zero sequence voltage 100 when a
saturated earth fault occurs the primary side the transformer. trans-
former error can create error the percentage range the open delta winding by
adding three large voltage indicators Une (U1E U2E U3E )/3.
UNE
n
Une
e
REG-DP
n
e
N
E
Figure 12: Une directly from the P-coil
n
Une
e
REG-DP
n
L1
L2
L3
e
A(U)
A(U)
A(U)
N(X)
N(X)
N(X)
da(e)
da(e)
da(e)
dn(n)
dn(n)
dn(n)
Figure 13: Une from the open delta winding
. small zero sequence volt-
ages, which are found during healthy operation, errors the percentage range are
relatively big values resulting incorrect tuning. the following the
secondary circuit specified lowercase letters.Page 29
Connecting the measurands the REG-DP
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