21
251/02 en
6
Parallel operation
6
Parallel operation
The voltage regulator can be run with the SKB 30 parallel
control unit (parallel operation of 2 to 6 transformers).
Another possibility is to use parallel operation of two trans-
formers which are each equipped with a voltage regulator
but without an additional parallel control unit (twin parallel
operation).
The selection is made with the following menu item:
The menu item is selected by pressing the SELECT key and the
keys and then using the SET and
k
eys to
choose between parallel operation with supplementary
device SKB 30 and the twin parallel operation.
Parallel operation (twin parallel operation)
This setting permits parallel control of two transformers on
one busbar.
Parallel operation management is handled via an RS 232
connection.
Activation of parallel operation is performed via the status
inputs terminals 90, 91.
Parallel control can be performed in two ways.
Parallel operation using the principle of "minimum circulat-
ing reactive current"
or
Parallel operation using the principle of "synchronism control
of tap-changer master-follower"
A menu item is used to select the principle of parallel
operation.
Select the menu item by pressing the SELECT key and the
keys and then setting the desired method of paral-
lel operation with jumper A (terminal 90/92), (see
fig. 8/9
).
Connect both parallel-operating voltage regulators via the
interface (see
fig. 7
).
The voltage regulators in parallel operation report the status
on terminals 80/81/82 and with LED
.
PARAL. OPERATION
TWIN PARALLEL
SKB/TWIN PARALL
25/30
7
to the second
TAPCON ® 230 VC / VC 100-BU-02
shielded cable, max. 25 m
TAPCON® 230 VC
SELECT PARALLEL
CIRCUL.REAC.CURR.
CRC/MAST/FOLLOW
19/30
7
6.1
Parallel operation with "Minimum Circulating
Reactive Current Method“
The circulating reactive current is computed from the trans-
former currents and their respective phase angles. For correc-
tion of the measuring circuit voltage, a voltage proportional
to the circulating reactive current is applied to self-suffi-
ciently operating regulators. This correction voltage can be
either decreased or increased through adjustment of the
"stability" (see paragraph 6.1.3).
If an inadmissibly high circulating reactive current is detec-
ted, all on-load tap-changers involved will be reset after only
10 s, regardless of the delay time preset at the regulator.
This method is suitable for transformers of comparable out-
put and u
k
, whether with uniform or with non-uniform step
voltage. No information on tap position is required.