ABB SPAD 330 C - Page 13

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Example 4. Biased differential relay SPAD 330 C used for
the winding short-circuit and interturn fault
protection of a Dyn11 connected power
transformer, when the current transformers
have “inside” earthings, i.e. the current
transformers have the basic connection type I.
Switch SG1
11
20
30
41
50
60
∑ = 9
Setting of the matching of the power transformer
vector group:
SPAD 330 C
SPAD 330 C
P1
S2
P2
S1
P2P1
S2
S1
L1
L2
L3
SPAD 330 C
B