The transition to modern, energy-efficient technology has a downside. Switching electronics such as LED lighting and AC drives increasingly cause disturbances in frequency ranges previously considered safe. High-frequency disturbances - often invisible to standard measuring equipment - pose a growing risk to the operational reliability of critical installations.
What is it: Pollution on voltage and current with frequencies above 2 kHz (often 2 kHz to 150 kHz, also called supraharmonics ).
The cause: The switching frequency of modern power electronics (inverters, LED drivers, EV chargers).
The danger: Unexplained failure of control systems (PLCs), flickering lighting, accelerated capacitor ageing and audible noise.
The challenge: Standard Power Quality analysers often measure only up to the 50th harmonic (2.5 kHz) and fail to see these disturbances.
The solution: specialist high-frequency measurements, EMC analysis and correct filtering or engineering.
High-frequency failures are not limited to one sector. This article is crucial for professionals responsible for the continuity and safety of:
For decades in the world of Power Quality, we mainly talked about harmonics: pollution in multiples of the mains frequency (50 Hz) up to about 2.5 kHz (the 50th harmonic). The evolution of technology has created a new problem area: the frequency spectrum between 2 kHz and 150 kHz, and sometimes even into the MHz range.
This phenomenon is known in professional literature as supraharmonics or high-frequency noise.
A comparison:
Imagine the electrical installation as a motorway. The 50 Hz voltage is the asphalt over which traffic (the current) travels. Classical harmonics are like holes in the road surface; you feel them pounding. High-frequency disturbances are not holes, but an intense, high-frequency vibration of the road surface itself. You don't see the holes, but the extreme vibration causes bolts to rattle loose and vehicles (equipment) to fail spontaneously for no apparent reason.
Why standard meters fail
Many technical services have basic Power Quality analysers. These are often designed according to the standard (such as EN 50160) and measure up to the 50th harmonic. If the interference is at 10 kHz or 50 kHz, the meter indicates a "perfect" sinusoidal signal, while in reality the connected equipment is exposed to harmful interference.
Ignoring high-frequency faults is a risk to continuity. Because these failures are often dismissed as "ghost failures", components are often replaced unnecessarily without addressing the source cause.
Why is this important for your operational reliability?
Paradoxically, the source of these woes is often the technology that helps us save energy. Almost all modern equipment uses Active Front Ends (AFE) or switching power supplies (SMPS).
To turn alternating current (AC) into direct current (DC) - or to drive a motor - the voltage is "chopped" (switched) thousands of times per second. This is done with components such as IGBTs or MOSFETs.
These switching frequencies, and their multiples, leak back into the electrical installation. When multiple devices (e.g. hundreds of LED drivers in an office building) switch at similar frequencies, resonances can occur or the signals can amplify each other. This results in complex voltage shapes that deviate far from the pure sine wave.
Nuance: It is not always one big piece of equipment that is the culprit. It is often the sum of many small sources (such as electronic VSAs of lighting) that together lift the grid pollution level above the immunity limit of sensitive equipment.
Since your standard multimeter or energy meter will not show anything out of the ordinary, pay attention to secondary symptoms. Be alert to the following signals:
Resolving high-frequency faults requires a systematic approach. Installing filters haphazardly often backfires and can exacerbate resonances.
1. Measuring with the right equipment (Diagnosis)
This is the most important step. You need a Power Quality analyser with a sampling rate high enough (e.g. 1 MHz or higher) to capture frequencies down to the kHz or MHz range. A standard measurement according to EN 50160 is not sufficient here.
2. EMC-correct design (Prevention)
For new installations or expansions, it is crucial to follow EMC(Electromagnetic Compatibility) guidelines.
3. Filtration and Conditioning (Mitigation)
If the source cannot be eliminated (after all, you need the AC drives), the pollution must be reduced.
Blind reliance on the grid operator: People often assume the voltage comes in "clean". However, in high-frequency faults, 95% of the time the cause lies within your own installation (with your own equipment).
Measuring with a multimeter: A True-RMS multimeter measures the total value, but cannot differentiate between 50 Hz and 10 kHz interference. You literally cannot see the problem.
Confusion with classical harmonics: An Active Harmonic Filter (AHF) is perfect for low harmonics (down to the 50th), but does nothing against disturbances of 20 kHz. Sometimes an AHF can even be negatively affected by these high frequencies.
Symptom control: replacing a faulty power supply with the exact same type, without removing the cause (the mains contamination). The new component will also fail quickly.
Poor earthing: Thinking low resistance (Ohms) is enough. For high frequencies, the impedance of the earthing is decisive. A long, thin earth wire acts like a coil for HF currents and blocks the discharge of interference.
Are you experiencing vague complaints in your installation? Walk through these steps before making any major investments.
Not every incident requires external help. However, in the following situations, waiting is risky:
HyTEPS has high-end measurement equipment that analyses frequencies down to the MHz range and engineers who translate data into a concrete solution.
Delve further into the subject matter via these related pages:
Symptoms are often subtle until things go wrong. Look out for unexplained machine failures, flickering lights, cables getting hot or transformers buzzing. Also, if electronics (PLCs, drivers) fail earlier than the service life indicates, chances are that the power quality is insufficient. A Power Quality measurement provides the answer.
This is possible, provided you have a high-quality Power Quality Analyzer (according to IEC 61000-4-30 Class A) and the knowledge to interpret the data. Collecting data is easy; analysing the correlation between events, harmonics and your specific business processes requires specialist engineering knowledge. We are happy to support you in the analysis.
Not by definition. NEN-EN 50160 describes the minimum requirements for voltage at the grid operator's transfer point. However, modern equipment can be more sensitive and malfunction even if the voltage is within this standard. We therefore look beyond the standard: we look at the compatibility between your power supply and your connected load.
Peace of mind, certainty and insight. You get a clear diagnosis of the 'health' of your electrical installation. We pinpoint the cause of faults, enabling you to avoid unplanned downtime and reduce fire risks or unnecessary energy losses. You receive a concrete advisory report with practical points for improvement.
No, that is a misconception. A filter is a powerful tool, but not a panacea. Sometimes the solution lies in changing transformer settings, redistributing loads or adjusting cabling. HyTEPS always recommends a thorough analysis and simulation before we recommend hardware, to avoid unnecessary investments.
Yes, significantly. Solar panel inverters and LED lighting drivers are non-linear loads that cause harmonics and sometimes supraharmonics. This can lead to interference with other equipment or overloading of the neutral conductor. When renovating or preserving, a Power Quality check is essential to ensure operational reliability.
We call this phenomenon 'nuisance tripping'. Often the cause is not the total amount of current, but the distortion of the current (harmonics) or short peak currents that your measuring equipment misses. This contamination can extra heat up thermal protections or confuse electronic protections, causing them to switch off wrongly. A specialised measurement can find out exactly why a protection reacts.
For a reliable picture, we usually measure at least one to two weeks. This is necessary to capture a full duty cycle, including weekends and peak loads. For specific acute failures, we can also take short-term measurements or deploy 'continuous waveform recording' to capture transients.
Your installer is an expert in installation and maintenance (the 'general practitioner'). HyTEPS is the specialist (the 'Power Quality Doctor'). We have advanced measuring equipment, simulation software and in-depth knowledge of theoretical electrical engineering and regulations. We often work together with installers to solve complex puzzles that fall outside standard knowledge.
After the measurement, you receive a report with conclusions in understandable language as well as technical details. If necessary, we simulate the possible solutions in our software. So you know exactly what the effect of a measure will be in advance. We then supervise the implementation and verify the result with a follow-up measurement.
Are you experiencing unexplained faults and suspect high-frequency interference? Our engineers will be happy to help you with a clear diagnosis or a second opinion. Speak to an engineer to discuss your situation.
HyTEPS
Beemdstraat 3
5653 MA Eindhoven
