Harmonic distortion is today one of the main threats to the stability and efficiency of industrial electrical systems. With the exponential growth of non-linear loads – from frequency converters in automation systems to LED technologies for industrial lighting – eliminating harmonic currents has become essential to ensure operational continuity and reduce energy costs.
In this technical guide you will discover the causes of harmonic distortion, the tangible damage it can cause to your system, and the advanced active filtering solutions developed by Ortea Next to permanently solve these Power Quality issues.
What harmonic currents are and what problems they cause to systems
Harmonic currents are frequency components that are multiples of the fundamental network frequency (50Hz in Europe) which overlap the perfect sinusoid of the power supply. These distortions are measured through the THD index (Total Harmonic Distortion), which quantifies the degree of harmonic pollution present in the system.
Definition of total harmonic distortion (THD)
According to CEI EN 50160, the limit for voltage THD is set at ≤ 8% for low voltage and ≤ 5% for medium voltage [Source: CEI EN 50160, 2024]. The international standard IEEE 519:2014 is even more restrictive, generally limiting current THD to 5% for most industrial users [Source: IEEE 519:2014].
Effects on transformers and cables
The presence of harmonics causes a series of technical and economic issues:
- Overheating of neutral conductors: Third-order harmonic currents add up algebraically in the neutral, causing overloads of up to 173% compared to the fundamental current [Source: Intone Power, 2024]
- Additional losses in transformers: Losses can increase by 10-15%, significantly reducing the useful life of components
- Protection malfunctions: Untimely trips causing unplanned downtime
Risk of failures and downtime
Average downtime costs caused by power quality problems range between €10,000 and over €100,000 for every hour of interruption in manufacturing and automotive industries [Source: International Technical Reports, 2024]. In highly automated plants, annual losses linked to power quality can reach 1% of annual turnover.
How harmonic currents are generated: causes and diagnosis
The proliferation of electronic equipment in modern plants has made harmonic distortion an increasingly widespread and problematic phenomenon.
Non-linear loads as a source of harmonics
The main harmonic generators in contemporary industrial plants are:
- Power electronic converters (inverters and VFDs for motor control)
- Switching power supplies (servers, computers, industrial automation)
- LED lighting systems with electronic ballasts
- High-power UPS systems
- Fast chargers for electric vehicles
- Industrial robotics and CNC machinery
All these devices draw current in a non-sinusoidal way, mainly generating odd-order harmonics (3rd, 5th, 7th, etc.) [Source: ABB Technical Papers, 2024].
The importance of an electrical network analysis
A proper Power Quality analysis is the first step to identifying distortion sources and sizing the optimal solution. Ortea Next offers in-depth diagnostic services including:
- Long-term measurements of voltage and current THD
- Identification of dominant harmonics
- Mapping of critical loads
- Assessment of impact on system components
Reference regulation: CEI EN 50160
The CEI EN 50160 standard defines the characteristics of voltage supplied by public distribution networks, establishing the quality limits that must be respected to ensure correct operation of user equipment. Compliance with these standards is essential to avoid penalties and guarantee operational continuity.
Is your system suffering from harmonic distortion? Speak with one of our experts for a free Power Quality analysis.
The Ortea Next solution: active filters to eliminate harmonic distortion
Ortea Next has developed a complete range of active filters representing the most advanced technological solution to permanently eliminate harmonic currents from electrical systems.
Operating principle of an active filter
Ortea Next’s ACTIVEmatic FA40 operate on an active cancellation principle: the system detects in real time the harmonic currents present in the system and injects currents of equal amplitude but opposite phase (180°), mathematically cancelling the distortion.
This process occurs through:
- Continuous sampling of load currents via current transformers
- Digital processing to identify harmonic components
- Controlled generation of compensation currents via PWM inverters
- Selective injection of corrective currents
Differences between active and passive filters
| Characteristic | Ortea Next Active Filters | Traditional Passive Filters |
| Compensation | Dynamic multi-band up to the 50th harmonic | Tuned to specific harmonics |
| Adaptability | Automatic response to variable loads | Fixed compensation |
| Effectiveness | THD reduction from 20-30% to <5% | Limited to design harmonics |
| Resonance risk | Absent | Present if poorly sized |
| Flexibility | High, including imbalance correction | Limited |
The ACTIVEmatic FA40 range of active filters by Ortea Next
The ACTIVEmatic FA40 series includes solutions from 25A to 800A for all industrial needs, with parallel configuration options for high-power plants. Each filter is designed with “Made in Italy” technology and backed by over 50 years of experience in the Power Quality sector.
Benefits and selection criteria of a harmonic filtering system
Investment in technologies to eliminate harmonic currents delivers measurable economic benefits and significant operational improvements.
Increased energy efficiency and cost reduction
Installing active filters enables:
- Up to 30% reduction in energy consumption linked to inefficiencies and additional losses [Source: Intone Power, 2024]
- Lower maintenance costs thanks to reduced thermal stress on components
- Avoidance of penalties for exceeding regulatory limits (up to €50,000/month in regulated sectors)
Greater reliability and longer equipment life
In our projects with industrial clients, we recorded an average 68% reduction in failures of sensitive equipment after installing ACTIVEmatic systems, resulting in increased plant availability and reduced premature replacement costs.
Regulatory compliance and Power Quality standards
Ortea Next’s active filters ensure compliance with all international standards:
- CEI EN 50160 for voltage quality
- IEEE 519 for harmonic distortion limits
- IEC 61000 for electromagnetic compatibility
How to size the correct filter for your system
Correct sizing requires a thorough technical analysis considering:
- Power and type of installed non-linear loads
- Time profile of harmonics (variations during the production cycle)
- Plant topology and optimal installation points
- THD reduction targets and regulatory requirements
Ortea Next provides its engineering team for free technical consultations and customised sizing.
Frequently asked questions about harmonic currents
Here are some frequently asked questions about harmonic reduction:
What THD level is considered critical?
Current THD values above 15-20% require immediate action to prevent equipment damage. IEEE 519 sets the general limit at 5%, while for critical applications (hospitals, data centres) values below 3% are recommended.
Do active filters also work for reactive power compensation?
Yes, Ortea Next’s ACTIVEmatic active filters also integrate dynamic power factor correction, simultaneously compensating reactive power and harmonic currents with a single solution.
Can an active filter be installed on an existing system?
Absolutely yes. Active filters are installed in parallel with the existing system without structural modifications. Installation is quick and can be carried out during normal maintenance windows. Request a technical consultation to assess feasibility for your system.
How long does it take to see the first results?
The benefits are immediate: the active filter starts compensating harmonics the moment it is switched on. Economic savings become evident from the first energy bill.
Contact us to size the ideal filtering solution for your needs. Our experts are at your disposal for a free and personalised technical analysis.
