Glossary
Electrical harmonics (armónicos eléctricos)
Currents and voltages at frequencies that are multiples of 50 Hz and distort the electrical waveform. They are produced by electronic equipment such as LED drivers, variable speed drives, computers, chargers and UPS units, and can heat cables and trip protective devices.
What harmonics are
Harmonics are parts of the current or voltage at a frequency that is a multiple of the grid frequency, which in Spain is 50 Hz (60 Hz in the US): the third harmonic runs at 150 Hz, the fifth at 250 Hz and so on. Added to the main wave they distort it, and the clean sine wave is no longer clean.
What produces them
Non-linear loads, which draw current in bursts rather than smoothly:
- LED drivers and old electronic fluorescent ballasts.
- Variable speed drives for motors, pumps and lifts (elevators).
- Computers, servers and office equipment.
- EV chargers, solar inverters and UPS units.
In a home they rarely cause trouble. In offices, shops with lots of LED lighting, warehouses with drives or buildings full of equipment, they can.
Problems they cause
- Neutral overheating on three-phase installations, because the third harmonic adds up on it.
- Unexplained tripping of RCDs and MCBs.
- Failures in capacitor banks, which can go into resonance.
- Heating of transformers and motors and shorter equipment life.
How they are measured and corrected
A power quality analyser is installed for several days to measure total harmonic distortion (THD) against the UNE-EN 50160 supply quality standard. Then the neutral can be upsized, filters fitted, detuned capacitor banks chosen or high-immunity RCDs used. As a guide, an analyser study costs 250 to 600 euros. See power factor correction in Seville, Spain.
Related services
Capacitors and reactive energy
We install power factor correction in Seville, Spain with a capacitor bank, so you stop paying the reactive energy surcharge that appears on the bills of many warehouses, workshops, hotels and shops. We measure with a power quality analyser, size the bank in kVAr and leave it adjusted so the penalty disappears.
Industrial maintenance
Industrial electrical maintenance for businesses in Seville, Spain: scheduled inspection plans for switchboards, motors, lines, lighting, UPS units and generators, thermal imaging to get ahead of breakdowns and call-outs for the ones that still happen, in warehouses, shops, offices and residential buildings with industrial-type installations.
High-immunity RCD
We fit a high-immunity RCD in Seville, Spain when yours trips for no reason with LED lights, the induction hob, inverter air conditioning or the EV charger. First we check there is no real earth leakage, then we choose the right RCD (high-immunity, type A, F or B) so it protects just as well and stops tripping.
Need an electrician in Seville, Spain?
Call us or send a WhatsApp message with a photo of the job. You get a fixed quote before any work starts.