Thanks to a staff of technicians dedicated to the realization of “special” projects, IREM is able to support customers in the choice of basic equipment, options and product customizations regarding both electrical and mechanical and aesthetic aspects.
IREM PROPOSAL FOR POWER QUALITY TAILOR MADE
VOLTAGE STABILISERS MINISTAB AND STEROSTAB
MINISTAB and STEROSTAB are the names of the two series of IREM electromechanical voltage stabilizers with electronic control suitable for any type of load, they supply a stabilized voltage at the true RMS value even in the presence of strong harmonic distortions of the network.
In relation to the characteristics of the electrical network to be compensated and the power of the loads to be powered, IREM Voltage Stabilizers are divided into 6 different types:
MINISTAB – STEROSTAB M: Single-phase voltage stabilisers.
MINISTAB – STEROSTAB T: Three-phase voltage stabilisers with common regulation of the 3 phases.
MINISTAB – STEROSTAB Y: Three-phase voltage stabilisers with independent regulation of each phase.
MAIN TECHNICAL CHARACTERISTICS
|Rated power||from 1kVA to 8000kVA|
|Supply voltage||from 110Vac to 500Vac|
|Voltage variation||± 10%, ±15%, ±20%, ±25%, ±30% (symmetrical configuration)
-35% +15% (symmetrical configuration)
|Output accuracy||± 1%|
|Protection degree||IP21, IP54|
Other configurations and technical features are possible on request.
What distinguishes the MINISTAB and STEROSTAB Voltage Stabilizers is the possibility of being completed with multiple optional equipment or being designed “tailor-made” according to customer specifications.
This is the reason why IREM voltage stabilizers can be defined as devices for POWER QUALITY TAILOR MADE.
TAILOR MADE VOLTAGE STABILISERS
ATTENUATION OF VOLTAGE SPIKES
This function is performed by means of surge arresters which protect both the AVR and the load against overcurrent of atmospheric origin and overvoltages. The following protection devices are available:
a. Class I lightning arresters (IEC 62305) wave form 10/350μs 150kA total, 8/20 μs 150kA total, Up < 1.3kV, reaction time <100ns.
b. Combined class I+II surge arresters (IEC 62305), wave form 10/350μs 25kA total, 8/20 μs 120kA total, Up < 1.1kV, reaction time <100ns.
c. Class II surge arresters (IEC 60364-4-44), wave form 8/20μs 120kA total, Up < 1.3kV, reaction time <25ns.
d. Class III surge protection device (IEC 60364-4-44) wave form 8/20μs and 1,2/50μs 60kA total, Up < 1.2kV, reaction time <50ns.
SHORT CIRCUIT PROTECTION
Ensured by means of thermal magnetic circuit breaker or fuses in input.
Ensured by means of thermal magnetic circuit breaker, current relay or fuses in output.
OVER/UNDER VOLTAGE PROTECTION
Ensured by voltage relay with load cut-off by means of thermal magnetic circuit breaker or contactor.
REVERSED PHASE SEQUENCE / PHASE FAILURE PROTECTION
Voltage monitoring relay with load cut-off by means of thermal magnetic circuit breaker or contactor.
OVER TEMPERATURE PROTECTION
A sensor detects when the temperature exceeds the alarm threshold in the most critical point of the AVR. The signal can:
- either activate the automatic by-pass or,
- disconnect the AVR through a contactor or a thermal magnetic circuit breaker.
It guarantees the supply of a stabilized voltage even in the first cycles of operation subsequent to a blackout. It is common, in fact, that following a blackout the lines supply very high voltages for a limited period.
The soft start protection can be implemented according to two methods to be defined in relation to the installation context and the type of load supplied:
- Through a power circuit that includes command and switching devices capable of connecting the load only when the voltage value at the output of the stabilizer is correctly restored and in tolerance. The command is implemented by a power contactor controlled by a timed relay.
- Through an auxiliary circuit that includes control and implementation devices capable of regulating the output voltage at the minimum value and then progressively rising to the nominal value. The command is implemented by the same system of regulation of the variable autotransformer powered by capacitors. In no case are accumulators used that require periodic replacement.
In the unlikely event of a failure of the AVR, the load will be directly powered from the mains. The internal functional bypass is performed by:
a. manual by-pass switch capable to withstand a current equal to or higher than the max input current of the AVR
b. 3 contactors which can be
- automatically activated when the sensors detect a critical operating condition or in case of AVR failure,
- manually activated by service people for maintenance purposes,
- activated by the remote control centre through the supervision software (password protected).
It is installed in a separate cabinet.
The load is directly connected to the mains ensuring the operation in case of maintenance. It is performed by a manual by-pass switch capable to withstand a current equal to or higher than the max input current of the AVR.
Besides ensuring galvanic isolation of the system, attenuating common-mode disturbances and creating a “clean neutral”, it also allows, when necessary, to transform the nominal supply voltage to the voltage value required by the load.
It is a magnetic component designed to create a reference neutral point in those three-phase systems where this is not available or is unstable.
INPUT/OUTPUT ADAPTING TRANSFORMER
It allows to adapt the nominal mains voltage to the value required by the load.
ATTENUATION OF COMMON MODE AND TRANSVERSE MODE NOISE
Ensured by EMI / RFI filters consisting of blocking coils and capacitors, it is able to attenuate high frequency noise.
It realizes the reduction of the harmonic current components generated by non-linear or variable loads, it can be active or passive to be chosen according to the spectrum of harmonics present in the system.
SMART MANAGEMENT OF THE PLANT
a. Automatic switching on a reserve stabiliser. When an anomaly is detected in the operation of the stabilizer, the supervision module automatically transfers the load to the reserve stabilizer.
b. Automatic switching to an emergency line. The AVR is connected to an emergency line when an abnormal condition of the main power supply is detected by the supervision module.
c. Device for unprivileged load switching-off. It automatically switches off unprivileged loads in case of AVR overload or to achieve energy saving.
d. Control module for programmed switching-on / off of loads. Capable to handle up to 8 lines, each of them can undergo 8 changes of state in 24 hours.
MODULAR SYSTEM FROM Y326
The three-phase voltage stabilizers of large power (from model Y326) are made of functional units in order to facilitate transport, handling, positioning and installation. Each functional unit corresponds to the relative singlephase section that will be connected to the system. The connection to the system of this type of voltage stabilizer does not require further interconnections between the units and is therefore very similar to the connection of a voltage stabilizer made in a single unit.
It allows remote monitoring of electrical parameters as well as acquisition of real-time information and historical data.
The analysis of this information and of any alarm signal and functional status allows to prevent the intervention of the automatic protection systems of the stabilizer that would otherwise cause the interruption of the process or, in the absence of these, to take action to remove the cause of the alarm conditions.
Communication via Internet modem (LAN or Mobile).
STORAGE OF ELECTRICAL, PHYSICAL AND ALARM STATUS PARAMETERS
It remotely allows the display, via web on PC, smartphone, web viewers and tablets, of data coming from the voltage stabilizer.
The web display of the electrical parameters of the voltage stabilizer is divided into two macro areas: real-time data and historical data. Historical data can be displayed on a freely selectable period in a column chart, the data thus displayed can be arranged in tabular format and exported to CSV for processing in Excel or another application tool.