Power Quality Improvement Guide: When to Install an Active Harmonic Filter, un generatore di Var statico, or Both

Modern industrial facilities rely heavily on power electronics, Drive di frequenza variabile (Vfds), servo systems, UPS units, Caricabatterie EV, robotic production lines, e sistemi di energia rinnovabile. While these technologies improve efficiency and productivity, they also introduce new power quality challenges that traditional capacitor banks can no longer solve effectively.

In qualità di ingegnere elettrico senior presso Coepower, I frequently receive the same question from customers:

Should we install an Filtro armonico attivo (Ahf), UN Generatore VAR statico (Svg), o entrambi?”

When to Install an Active Harmonic Filter, un generatore di Var statico, or Both - Coepower

The answer depends entirely on the power quality problems present in your electrical system. Installing the wrong solution can waste money while failing to solve the actual issue.

In this guide, I’ll explain the differences between Active Harmonic Filters and Static Var Generators, how they work, their ideal applications, and how to determine whether your facility requires one—or both.

Understanding Today’s Power Quality Problems

Power quality generally involves four major issues:

  • Distorsione armonica
  • Basso fattore di potenza
  • Fluttuazioni di tensione
  • Squilibrio trifase

In modern factories, these problems often occur simultaneously.

Common sources include:

  • Drive di frequenza variabile (Vfds)
  • Servomotori
  • Sistemi UPS
  • Macchine a CNC
  • Attrezzatura di saldatura
  • Data center
  • Renewable energy inverters
  • Stazioni di ricarica EV
  • Medical imaging equipment

These nonlinear loads generate harmonic currents while consuming reactive power, resulting in higher electricity costs, surriscaldamento dell'apparecchiatura, transformer overload, and unexpected downtime.

Cos'è un filtro armonico attivo (Ahf)?

UN Filtro armonico attivo (Ahf) is an intelligent power electronic device designed to eliminate harmonic currents in real time.

Instead of using passive inductors and capacitors tuned to specific frequencies, an AHF continuously monitors the load current and injects equal but opposite harmonic currents into the electrical network.

The unwanted harmonics are effectively canceled before they can propagate throughout the power system.

Main Functions of an Active Harmonic Filter

  • Eliminate 2nd–50th order harmonics
  • Reduce Total Harmonic Distortion (Thd)
  • Prevent transformer overheating
  • Protect sensitive equipment
  • Reduce neutral conductor current
  • Improve power system reliability
  • Prolungare la durata delle apparecchiature

Modern AHFs can achieve harmonic compensation efficiencies exceeding 95%, making them ideal for facilities with rapidly changing loads.

Typical Applications for Active Harmonic Filters

AHFs are commonly installed in:

  • Impianti di produzione
  • Data center
  • Fabbriche di semiconduttori
  • Ospedali
  • Edifici commerciali
  • Impianti di trattamento dell'acqua
  • Olio & impianti gas
  • Impianti siderurgici
  • Operazioni minerarie
  • Stazioni di ricarica EV

These environments contain significant nonlinear loads that continuously generate harmonics.

Che cos'è un generatore Var statico (Svg)?

UN Generatore VAR statico (Svg) is an advanced reactive power compensation device designed to improve power factor dynamically.

A differenza dei tradizionali banchi di condensatori, an SVG uses high-speed IGBT technology to generate leading or lagging reactive current instantly according to load demand.

Instead of waiting for contactors to switch capacitor stages, an SVG responds within milliseconds.

This enables continuous, precise power factor correction without overcompensation.

Main Functions of an SVG

An SVG provides several important benefits:

  • Compensazione dinamica della potenza reattiva
  • Power factor correction up to 0.99
  • Stabilizzazione della tensione
  • Reduction of line losses
  • Increased transformer capacity utilization
  • Miglioramento dell'efficienza energetica
  • Compensation of inductive and capacitive loads

A differenza dei banchi di condensatori, SVGs are unaffected by harmonic resonance and remain stable under rapidly fluctuating loads.

Typical Applications for Static Var Generators

SVGs perform exceptionally well in:

  • Produzione automobilistica
  • Acciaierie
  • Impianti di cemento
  • Fabbriche tessili
  • Porti
  • Aeroporti
  • Parchi eolici
  • Centrali solari
  • Commercial complexes
  • Large HVAC systems

Any installation with fluctuating inductive loads can benefit significantly from SVG technology.

Filtro armonico attivo vs generatore var statico

CaratteristicaFiltro armonico attivo (Ahf)Generatore VAR statico (Svg)
Funzione primariaMitigazione armonicaCompensazione del potere reattivo
Solves Harmonics✔ Excellent✘ No
Improves Power FactorLimitato✔ Excellent
Voltage StabilityModerareEccellente
Dynamic Response<1 SM<10 SM
Eliminates Resonance✔ Yes✔ Better than capacitor banks
Ideale perCarichi non lineariBasso fattore di potenza
Main BenefitTHD più bassoLower reactive power charges

One common misconception is that an SVG can eliminate harmonics.

It cannot.

Similarly, while some AHFs can provide limited reactive power compensation, their primary purpose is harmonic suppression rather than full power factor correction.

When Should You Install an Active Harmonic Filter?

An AHF is the right choice if your facility experiences:

High Harmonic Distortion

Typical indicators include:

  • THDi > 20%
  • THDv exceeding IEEE 519 recommendations
  • Scatti frequenti dell'interruttore
  • Surriscaldamento del trasformatore
  • Surriscaldamento del motore
  • Malfunzionamento dell'apparecchiatura sensibile

Large Numbers of VFDs

Facilities with many variable speed drives often experience severe harmonic pollution.

UPS Systems

Large UPS installations produce significant harmonic currents.

Data center

Servers, switch-mode power supplies, and UPS systems generate harmonics continuously.

Production Lines with Power Electronics

Modern automated manufacturing relies heavily on inverters and servo drives.

When Should You Install a Static Var Generator?

An SVG is recommended when:

Low Power Factor Increases Electricity Bills

Utilities often impose penalties when power factor falls below required levels.

An SVG can improve power factor close to unity.

Rapidly Changing Loads

Examples include:

  • Gru
  • Elevatori
  • Spot welding
  • Compressori
  • Macchine per stampaggio ad iniezione

I banchi di condensatori tradizionali non possono rispondere abbastanza rapidamente.

Voltage Fluctuation

SVGs provide dynamic reactive support to stabilize voltage.

Capacitor Bank Failures

Many facilities replace aging capacitor banks with SVGs because SVGs:

  • require less maintenance,
  • eliminate switching transients, E
  • avoid capacitor degradation.

When Should You Install Both an AHF and an SVG?

In many industrial facilities, both harmonic distortion and reactive power problems exist simultaneously.

Typical examples include:

  • Produzione automobilistica
  • Steel production
  • Semiconductor fabrication
  • Data center
  • Petrochemical plants
  • Fabbriche intelligenti
  • Stazioni di ricarica EV

In these cases, installing both technologies delivers the best long-term results.

Benefits of a Combined AHF + SVG Solution

By integrating an Active Harmonic Filter with a Static Var Generator, facilities can achieve:

  • Soppressione armonica
  • Dynamic power factor correction
  • Reduced electricity penalties
  • Improved voltage stability
  • Lower transformer temperature
  • Increased system efficiency
  • Longer equipment life
  • Greater production reliability
  • Conformità con IEEE 519 and other power quality standards

Many modern power quality cabinets integrate both AHF and SVG modules into one compact solution, reducing installation space while simplifying maintenance.

Perché i banchi di condensatori tradizionali non sono più sufficienti

For decades, capacitor banks were the standard solution for power factor correction.

Tuttavia, today’s electrical systems are dramatically different.

Capacitor banks have several limitations:

  • Slow response speed
  • Mechanical contact wear
  • Harmonic resonance risk
  • Fixed compensation steps
  • Poor performance under fluctuating loads

As facilities adopt automation, energia rinnovabile, and digital manufacturing, intelligent compensation devices have become the preferred solution.

SVGs and AHFs provide real-time compensation without the drawbacks associated with conventional capacitor banks.

How CoEpower Helps Improve Power Quality

A Coepower, we understand that every electrical system is unique. Selecting the right power quality solution requires more than simply choosing a product—it requires a thorough analysis of your electrical network.

Our engineering team begins by evaluating key parameters such as:

  • Distorsione armonica totale (Thd)
  • Fattore di potenza
  • Carica profilo
  • Transformer loading
  • Fluttuazioni di tensione
  • Richiesta di potere reattivo
  • Future capacity expansion

Based on this assessment, we recommend the most cost-effective solution:

  • Filtro armonico attivo per la mitigazione armonica,
  • Generatore VAR statico for dynamic reactive power compensation, O
  • A combined AHF + SVG solution for comprehensive power quality improvement.

Our systems feature advanced DSP control, fast dynamic response, modular design for flexible capacity expansion, and reliable performance in demanding industrial environments. Whether your facility is upgrading an existing electrical system or designing a new installation, CoEpower solutions help reduce energy losses, migliorare l'affidabilità delle apparecchiature, and ensure long-term compliance with international power quality standards.

Considerazioni finali

There is no universal solution to power quality issues.

If your facility struggles primarily with harmonic distortion, an Filtro armonico attivo is the appropriate investment.

If poor power factor and fluctuating reactive power are increasing operating costs, UN Generatore VAR statico offers a more effective solution than conventional capacitor banks.

Tuttavia, many modern industrial facilities experience both problems simultaneously. In these cases, combining an AHF with an SVG delivers the highest level of power quality, improved system reliability, costi energetici ridotti, and better protection for critical electrical equipment.

As industrial power systems become increasingly complex, proactive power quality management is no longer optional—it is essential for maximizing efficiency, minimizing downtime, and supporting sustainable operations.

Domande frequenti (Domande frequenti)

Can an Active Harmonic Filter replace a Static Var Generator?

Not completely. While some AHFs can provide limited reactive power compensation, they are primarily designed to eliminate harmonics. For significant power factor correction, an SVG is the better solution.

Does an SVG eliminate harmonics?

NO. An SVG is designed to compensate reactive power and stabilize voltage. It does not actively suppress harmonic currents.

Can I use both an AHF and an SVG in the same electrical system?

SÌ. Infatti, many industrial facilities benefit from installing both devices to address harmonic distortion and reactive power compensation simultaneously.

Are AHFs and SVGs better than capacitor banks?

For modern electrical systems with nonlinear and rapidly changing loads, AHFs and SVGs offer faster response, greater accuracy, and improved reliability compared with conventional capacitor banks.

Tag di parole chiave

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