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Connecting the measurands the REG-DP
8.
The P-coil's winding generally designed apply zero sequence voltage 100 when a
saturated earth fault occurs the primary side the transformer. Connecting the measurands the REG-DP
8.1 Connecting the zero sequence voltage
Regulation should based the zero sequence voltage measured the P-coil. small zero sequence volt-
ages, which are found during healthy operation, errors the percentage range are
relatively big values resulting incorrect tuning. trans-
former error can create error the percentage range the open delta winding by
adding three large voltage indicators Une (U1E U2E U3E )/3. the following the
secondary circuit specified lowercase letters.
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
