3
Operation
principle
The voltage regulating module SPCU 1D50
compares the measured secondary voltage U
m
of the transformer to the control voltage U
p
.
The control voltage U
p
is composed of the set-
ting value U
s
, the line-drop compensation value
U
z
, the circulating current compensation value
U
ci
and the reduce set voltage value U
rsv
, i.e. U
p
= U
s
±
U
z
±
U
ci
- U
rsv
.
The parameter
∆
U
s
denotes the hysteresis,
which is active around U
p
, within which no
regulation takes place. If, for instance, U
p
= 100 V
and
∆
U
s
= 1.5%, the module does not generate
a raise or lower command, when the measured
voltage is in the range U
m
= 98.5… 101.5 V. If
the measured voltage is below 98.5 V or above
101.5 V, the adjustable delay time T1 starts. This
delay time is running as long as U
m
is outside
the
∆
U
h
limits. The factory setting of
∆
U
h
is
90% of
∆
U
s
. If U
m
does not rise or fall within
the limits of
∆
Uh during the delay time, the
output signal is activated. Should, however, the
voltage U
m
rise or fall within the
∆
U
h
limits
during the delay time, the delay counter is reset
and the module does not provide a control sig-
nal.
After the first control signal from the regulat-
ing module, the voltage U
m
may still be outside
the limits of
∆
U
s
. Then the second adjustable
delay time T2 starts. The setting of this delay is
normally shorter than T1. T1 and T2 can both
be given either a fixed value or a value depend-
ing on the difference between U
m
and U
p
. This
deviation U
m
- U
p
, expressed as U
d
, can be read
on the display of the module. When the delay
time depends on the deviation, it is inversely
proportional to the U
d
/
∆
U
s
ratio and thus also
depending on the set value of
∆
U
s
.
Control voltage U
p
The voltage regulating module constantly regu-
lates the secondary voltage towards U
p
. The
control expression has the following form:
U
p
= U
s
±
U
z
±
U
ci
- U
rsv
U
s
= reference voltage
U
z
= line-drop compensation value
U
ci
= circulating current compensation value
U
rsv
= reduce set voltage value
Reduce set voltage
The reduce set voltage feature can be used for
load shedding or simple line drop compensa-
tion purposes. The set voltage is reduced by ac-
tivating the RSV 1/2 or RSV 1/1 binary input.
Activating the RSV 1/2 input reduces the set
voltage by half the setting value RSV and acti-
vating the RSV 1/1 input reduces the set volt-
age to the full extent of setting value RSV. If
both inputs are active, the RSV 1/1 input has
priority and the set voltage is reduced to the
full extent. The setting value RSV is selectable
in the range 0.00...9.00%. Software switch
SGF2/8 has to be set and SGF2/1 has to be
cleared if both inputs are used.
Second settings
Either main or second settings can be selected
as currently used settings. Switching between
main and second settings can be done in three
different ways:
1) Over the serial communication, using the
command V150.
2) Via the push-buttons on the front panel and
subregister 4 of register A. The setting 0 acti-
vates the main settings and the setting 1 acti-
vates the second settings.
3) By setting the switch SGF1/6 into position
1. Then the selection of main or second set-
tings depends on the regulator operation
mode. If single operation is used, main set-
tings are valid and if parallel operation is used,
second settings are valid. Setting the switch
SGF1/6 into position 1 deactivates param-
eter V150 and subregister 4 of register A.
Note! To become active, the switch must be
set into position 1 in both setting banks.
