Digital Voltage Stabilizer-Outdoor

 Unit IP54 (NEMA 3R+) 200-600kVA


The three-phase DIGIT@L line of voltage stabilizers is based on columnar voltage regulators and covers the
range from 200kVA to 6000kVA. All models have a robust construction suitable for industrial applications and
allow for a choice of several input voltage variation percentages within a broad range (from +30% up to -45%).

They are made available as a standard option in outdoor IP54 enclosures.  A 630kVA unit is shown above, other
sizes and Medium Voltage units are available on request.

The DIGIT@L voltage stabilizers are supplied with independent regulation on each phase so a neutral
connection is essential. The DIGIT@L type can be used when the main supply is unbalanced and it is
suitable for supplying three-phase loads, two-phase loads and single-phase loads.

The stabilizers are air cooled, with natural convection up to 45°C and aided by fans when temperature rises
above 45°C.

Control System

The measuring instrumentation for the DIGIT@L stabilizers is incorporated in a control panel on the cabinet door and consists of two
multi-task digital network analyzers. These instruments are able to provide information regarding the status of the lines upstream and downstream of the voltage stabilizer such as phase and linked voltages, current, power factor, active power, apparent
power, reactive power, etc. The front panel is provided with an LED user friendly interface which allows for complete monitoring of the
unit (by indicating the status of the three regulators and the possible alarms).



LED lights are provided for each phase signaling ‘power on’, reaching of voltage regulation limits and direction of voltage regulation
Alarms for minimum and maximum voltages, maximum current, over temperature, cabinet overheating and maintenance required
are also indicated.

The alarm indicators are accompanied by an acoustic alarm. The logic control, performed on true RMS voltage, is based on a 2-wayDSP microprocessor. This not only allows for monitoring but also allows all parameters of the stabilizer to be set up via a PC.


Working Principle

The control circuit compares the output voltage value to the preset desired value. When the percentage variation is too high, the control drives the voltage regulator gear motor. By doing so the regulator rollers change their position thus varying the voltage drawn and supplied to the buck/boost transformer primary winding. The secondary voltage of the buck/boost transformer will be in phase or in opposition to the supply,  so the voltage drawn from the regulator is added or subtracted to the mains voltage, thus compensating for its variations