14
M
M
Raise
Lower
Raise
Lower
U12
Raise'
Raise'
Lower'
Lower'
Man'
Aut/Man
Auto'
Auto'
Man'
-
-
-
-
+
+
R2
SPAU 341 C1
CB1
CB2
CB3
TR1
TR2
R1
SPAU 341 C1
TCO
TCO
TCO
U12
IL1
IL2
IL3
IL1
IL2
IL3
~
N
~
N
N
N
SGF1/1=0
SGF2/8=0
SGF2/8=0
SGF1/1=0
SGF2/6=0
SGF2/7=0
SGF2/6=0
SGF2/7=0
N
N
N
N
Fig. 7. The voltage regulator SPAU 341 C1 in parallel operation using the master/slave principle.
Three phase currents measured on the primary side of the transformer for overcurrent blocking
purpose. No line drop compensation used. Automatic selection of master regulator using digital
inputs. The TCO signal from the tap-changer with the longest operate time is connected to the
regulators to prevent regulating pulses during tap-changer operation.
Table 1. Regulator mode compared to circuit breaker configuration
CB 1
CB 3
Regulator 1
Regulator 2
open
open
as before
as before
closed
open
automatic (master)
manual (slave)
open
closed
manual (slave)
automatic (master)
closed
closed
automatic (master)
manual (slave)