Within the context of power quality analysis studies, the term supraharmonics refers to spectral components of voltage and current that occur at frequencies beyond the classical harmonic range, typically above the 40th–50th harmonic of the fundamental frequency, i.e., above 2 kHz, as defined by contemporary literature and IEC standards.
The growing integration of power electronic devices into electrical networks, such as photovoltaic inverters, electric vehicle chargers, switched-mode power supplies (SMPS), and variable speed drives, has made supraharmonics a significant contributor to power quality deterioration. These devices employ high-speed semiconductor switching elements (IGBTs and MOSFETs based on SiC and GaN technologies), operating with pulse-width modulation (PWM) techniques and switching frequencies in the kHz range.
In photovoltaic installations in particular, the parallel operation of multiple inverters can lead to an accumulation of supraharmonic emissions, potentially causing resonances with network components such as cables, LCL filters, and transformers. Such interactions may result in increased losses, thermal stress, accelerated equipment aging, or even insulation failures, while often remaining undetected by conventional power quality indices such as total harmonic distortion (THD).
Accurate assessment of supraharmonics requires the use of Class A power quality analyzers with high sampling rates and extended spectral analysis capabilities. For example, the latest generation of Fluke 1770 analyzers enables supraharmonic measurements up to approximately 30 kHz, while the HIOKI PQ3198 extends the measurable frequency range up to 80 kHz, effectively covering most of the supraharmonic spectrum. These instruments therefore align with current measurement requirements and the forthcoming revisions of IEC 61000-4-30, allowing for a more comprehensive and precise characterization of actual power quality in modern energy systems.