Active Voltage Conditioner (AVC) Details

Voltage Correction for Low and Medium Voltage Applications

The AVC continuously monitors the 3 incoming supply phase voltages. If there is any deviation from the nominal voltage level, the AVC inserts an appropriate compensating voltage using an IGBT inverter and series injection transformer. For the duration of any voltage sag, additional current is drawn from the line supply. The AVC continuously regulates the load voltage, thus reducing voltage disturbances from the utility supply, which can otherwise adversely affect the loads.

AVC Performance & Single Line Diagram

The AVC provides:

• Complete correction of three-phase utility sags to nominal voltage up to the specified correction level of the AVC model (e.g. 30%), for 30 seconds at full load.
• Correction of balanced three-phase utility sags down to 50% and single phase sags down to 30% of nominal voltage back to an acceptable voltage level, depending on correction level of AVC model, for at least 30 seconds.
• Continuous regulation of three-phase utility under-voltages and sags down to 90% of the nominal supply voltage. Option available for deeper continuous sag correction.
• Continuous regulation of three-phase utility over-voltages and surges up to 110% of the nominal supply voltage with Enhanced Regulation AVCR model.
• Correction of utility phase voltage unbalance.
• Attenuation of flicker voltages in the supply.
• Automatic Line drop compensation

The Active Voltage Conditioner provides the user with a high quality supply, protecting the load from the majority of common voltage disturbances. All electronic equipment has some tolerance to voltage variation so it is rarely necessary for voltage to be at nominal for equipment to continue operating.

AVC

Application Voltages & Power Ratings

The AVC is available for application at low voltage (208V-690V)for loads 25kVA to 5MVA and at Medium Voltage (1kV-36kV) for loads 1MVA – 50MVA

Extremely Fast Voltage Sag Correction

The AVC provides an extremely fast (<1msec) response to voltage sag events, with complete voltage correction achieved within half a cycle. The response is much faster than many other voltage correcting products.

Protection Against Multiple or Extended Voltage Sags

The AVC has no internal electrical storage so can respond instantly to multiple sag occurrences. It provides complete regulation for voltage sags within its rated correction range for at least 30sec, and partial correction for three-phase sags to 50%, and single-phase-to-ground sags to 30% for at least 30sec. This ensures sensitive electronic loads will continue operating normally if supply voltage varies. 

Superior Regulation Accuracy

The AVC provides continuous regulation to within -1% of the nominal voltage set-point when the supply voltage varies within the 90% – 100% range (or ±1% within the 90% - 110% range for the Enhanced Regulation model AVCR.) The output is regulated continuously, not just when the supply voltage falls below a preset value as for other voltage correcting products. There are no discrete step voltages added into output waveform.

Unbalanced Voltage Correction

The AVC corrects unbalanced voltages from the supply. If voltage unbalance is present in the supply this significantly increases the currents drawn by three-phase induction motors and decreases their lifetime. The AVC corrects this.

Monitoring

The AVC incorporates the necessary controls, measurements, indicators and alarms to allow the operator to monitor the system status and performance, and take any appropriate action. It includes a plain English 4x20 character LCD and retains both a fault log and voltage event log. 

High Efficiency

The AVC has a typical efficiency of >98% at full load and close to 99% for low voltage products 208-690Volts.

High Reliability - Rugged Overload Capability

The AVC consists of proven inverter based technology that has been used successfully in industry for almost 20 years.

The AVC is rated for 150% overload (of the rated load kVA) when providing 10% continuous correction.

Loads Remain Connected to Supply

Only the primary of the injection transformer is in series with the load, so even if the electronics are in bypass mode, the load is not dropped.

Optional Features

Flicker Voltage Correction

The AVC attenuates flicker voltages in the supply voltage below industry accepted discomfort thresholds.

Flicker voltages produce a flickering light in coiled filament, fluorescent and arc lamps, which becomes more noticeable as the voltage variation frequency approaches 8.8Hz. Flickering light can cause annoyance, discomfort, medical problems and reduce productivity of those working in such an environment.

Line Drop Compensation

The AVC can be configured and re-rated to provide continuous line impedance compensation even if the unit is to provide more than 10% continuous under-voltage correction. The AVC corrects the voltage drop along long lines caused by large loads and allows the voltage at the load to remain at its desired nominal value.

Over-Voltage Correction

The AVCR enhanced regulation version provides correction of long-term overvoltages as well as the more common voltage sags. Overvoltages occur when utility capacitors are not switched off during periods of light demand e.g. evenings and weekends. The resulting supply voltages can be well above nominal values and cause problems for UPS systems and other sensitive equipment. The AVCR will correct these and can hold the voltage within ±1% of nominal.

Examples of how much you can save

Which solution is right for you? AVC Selection Guide

Low Voltage - Active Voltage Conditioners

Medium Voltage - Active Voltage Conditioner

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