The voltage stabiliser is made essentially of buck-boost transformer, voltage regulator and electronic control. By means of the digitally controlled system, the stabiliser is able to compensate for a widely fluctuating incoming voltage stabilising it within a ±0.5% accuracy range in relation to the rated value. Based on a microprocessor sampling the output voltage at high frequency, the control system operates the voltage regulator motors in order to guarantee the voltage stability.
The voltage regulator is an autotransformer with variable transformer ratio, effectively performing the voltage adjustment. Depending on the rated power of the stabiliser, the regulator can be columnar or toroidal. The stabilisation takes place on the ‘rms’ value of the voltage and is not affected by harmonic distortion in the mains. The stabiliser can operate with a load variation range from 0 to 100% with a regulation speed depending on the input voltage percentage variation and on the design (indicatively, it can vary between 8 and 30msec/V).
The voltage stabiliser is not affected by the load power factor and since regulation is performed without chopping the voltage sine wave, neither an appreciable harmonic distortion nor a phase displacement is introduced on the downstream line. The equipment is housed in an IP21 metal enclosure with RAL7035 finish. The standard stabilisers are air cooled (naturally or with aided ventilation over a certain temperature).
SIRIUS stabilisers are based on ORTEA columnar voltage regulators which allow for high ratings (up to 6000kVA) to be reached and achieve solid and reliable construction in order to satisfy any industrial need. The three-phase SIRIUS line allows for the choice of several input voltage variation percentages within a broad range (from +30% down to -45%).
The SIRIUS voltage stabilisers are supplied with independent regulation on each phase, therefore the presence of the neutral wire is required. The stabiliser can also operate without neutral wire by adding a D/zn isolating transformer or a neutral inductance).
The SIRIUS type is used when the main is unbalanced and it is suitable for supplying three-phase loads, two-phase loads and single-phase loads. The stabilisers are air cooled, with natural convection up to 45°C and aided by fans when temperature is above 45°C.
The measuring instrumentation for the SIRIUS stabilisers is incorporated in a control panel on the cabinet door and consists of two multi-task digital network analysers. Such instruments are able to provide with information regarding the status of the lines upstream and downstream the voltage stabiliser such as phase and linked voltages, current, power factor, active power, apparent power and reactive power. The readings are stored locally by the control system and (if the Ethernet connection is established) sent to a server at Ortea’s HQ, thus providing the Service centre with the necessary information. The front panel is provided with a user-friendly LED interface which allows for a complete monitoring of the unit. LED lights are provided for each phase signalling ‘power on’, reaching of voltage regulation limits and direction of voltage regulation (increase/decrease). 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 control system has been renewed and it is able to interface with the Internet thanks to its capability to connect with ETHERNET and GPRS protocols. This allows for a remote monitoring of the equipment made by ORTEA at its headquarters, thus guaranteeing prompt assistance worldwide. The control system is also provided with two USB ports for downloading the stored data on a memory key and uploading setting parameters if operating modifications in the system are needed. It’s also possible to update the control firmware either with USB port or with Ethernet connection. The SIRIUS stabiliser is provided with an electronic voltage regulator protection system activates in case of overload on the voltage regulator. In such condition the load supply is not interrupted, but the stabiliser output voltage is automatically set to the lower between the mains voltage and the pre-set output voltage. The service continuity is guaranteed, although the voltage is not stabilised. When the overload condition ceases to exist, the stabiliser switches automatically back to regular functioning. The logic control, performed on the true RMS voltage, is based on two 2-way DSP microprocessor (one performing the control and the other one managing the measurements). The user can monitor the system and set all the parameters of the stabiliser via a PC connection. The whole system is supervised by a third ‘bodyguard’ microprocessor controlling the correct functioning of the other microprocessors. The output voltage is reset to the minimum value in case of blackout by means of supercapacitor banks in oder to ensure the correct shutdown. All SIRIUS stabilisers are provided with SPD surge arrestors Cl. I and Cl. II.
Remote communication system.
The new all-in-one control card manages also the remote communication to the voltage stabiliser. This remote data monitoring system enables the user and Ortea Service Centre the chance of monitoring on-line the stabiliser wherever installed by means of specially designed software. The card is fitted with a local display (showing alarms and setting parameters) and with a keypad. Should the Ethernet connection not be available, the remote communication can be performed via an embedded GPRS modem. A common SIM data card purchased locally and inserted in the modem allows for a simple data transmission.