Single Phase Voltage Regulator RAV-2
with control CTR-2
Instruction Manual MI-010
Page: 26/27
Rev. 06/2017
Table 15: Options of days of the week
Valor
1 2 3 4 5 6 7
Week Day
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
OPERATING WITH EXTERNAL VOLTAGE SOURCE
CTR-2 Control can work with external power source for configuration and testing. External power source needs to
be from 90Vac to 145 Vac connected to terminals located on the front panel of control box, identified as
“External supply” keeping phase and neutral indication and placing “Normal / Disconnect / External)” in “External”
position.
DANGER: Correct polarity has to be connected on control. Not doing this will cause a short
circuit in power supply and damage to control unit
DANGER: Do not connect any power source in terminals of Voltmeter, as it may cause high
tensions in bushings with risk to operator and regulator
DANGER: Do not connect any power source in terminals of Voltmeter, as it may damage the VT
used for tension reference adjustment
LINE DROP COMPENSATION
Regulators can be installed at some distance from the theoretical load center. This means that the load will not be
treated with suitable voltage level as line losses between controller and this point are not considered. Considering
line losses are proportional to the load current and the impedance of the line in the segment the voltage drop
between the regulator and the theoretical center can be calculated. With this value regulator can increase its voltage
such that the regulation occurs as if the reference voltage was measured on the theoretical load center. To grant the
regulator the ability to regulate voltage at the theoretical load center, a circuit is incorporated to the control which
can be configured to represent an image proportional to the actual reference voltage circuit. Normally this circuit is
composed of a current transformer (CT) that produces current proportional to the load current and variable resistive
elements (R) and inductive variables (X) through which the current flows. When the load current increases, the
resulting current flowing from the CT through these elements produces voltage drop that simulates the voltage drop
in the primary line of the TC .
The CTR -2 controls calculated, by internal algorithm, the voltage drop due to resistance and reactance based on
proportional to the load current signal obtained by the CT , and the values of voltage drop due to resistance and
reactance that can be programmed for each of the maps ( 1,2,3 and inverse fIow) in the functions identified as " Ur -
V " and " Ux - V " that can assume values from -25 V to + 25 V .
VREft=
VREFv
2
−Ur∗senφ−Ux∗cosφ∗ I /200
2
I /200∗Ur∗cosφ− UX∗senφ
where:
"VREft" is effective reference voltage;
"VREFv" is voltage reference set in actual map;
"Ur" is the value, in volts, set for resistive voltage drop in active map;
"φ" is phase shift between current and tension;
"Ux" is the value, in volts, set for reactive voltage drop in active map;
"I" is current in mili-ampers measured by CTR-2.
To select adequate values of “Ur – V” and “Ux – V” knowledge of power line to be regulated is needed and to
determine theoretically or in fact, voltage drop when current is the nominal current of the regulator and divide by the
relation between line tension and control reference.
ITB - Equipamentos Elétricos Ltda.
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