Harmonic Measurement Features of ION7300 Series Meters

Issue

Questions regarding how harmonic currents and voltages are measured by ION7300 series meters, whether harmonic current is included in RMS measurements, and the impact of harmonic filters on measured current levels.

Product

ION7300 Series Power Meters

Environment

• Power quality monitoring and analysis
• Industrial and commercial electrical systems
• Applications involving harmonic loads and filtering

Cause

Harmonics are naturally present in electrical systems with non‑linear loads. Understanding how the ION7300 measures and reports harmonics is essential to correctly interpret RMS values and evaluate the effectiveness of harmonic mitigation solutions such as filters.

Resolution

Harmonic currents and voltages in the ION7300 series meters are obtained using a Fast Fourier Transform (FFT) applied to the digitized voltage and current waveforms.

The harmonic current is part of the RMS current measurement, as the RMS value reported by the meter is calculated on a sample‑by‑sample basis and includes all frequency components observed by the meter, not only the fundamental frequency.

Installing a harmonic filter may reduce the measured incoming current, but this outcome depends on several factors, including the type of harmonic filter used, the meter’s location relative to the filter and the load, and the characteristics of the load itself.