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One-Cycle Windowed-DFT Harmonic Estimation with Spectral-Interference Compensation
Chemseddine Allioua1, Alessandro Mingotti2, Roberto Tinarelli2
1Independent Researcher, 37134 Verona, Italy.
Sensors (Basel, Switzerland)
|July 28, 2026
Summary
This study introduces a new method for accurate harmonic estimation in power systems using single-cycle data. It corrects errors caused by frequency variations, enabling faster and more precise power quality monitoring.
Area of Science:
- Electrical Engineering
- Signal Processing
Background:
- Modern power quality monitoring requires per-cycle harmonic estimation due to fast-varying distortion sources.
- Off-nominal fundamental frequency in single-cycle analysis causes spectral interference, leading to systematic errors in harmonic phasor estimation.
Purpose of the Study:
- To present a lightweight, non-iterative harmonic estimation module for fixed-rate, one-cycle data streams.
- To address and correct spectral interference caused by windowing under off-nominal frequency conditions.
Main Methods:
- Leverages an external frequency estimate to model spectral interference as a linear mixing process.
- Applies algebraic inversion to recover unbiased harmonic phasors without adaptive resampling or variable window lengths.
- Designed as a plugin component for existing power quality processing chains.
Main Results:
- Achieves machine-precision accuracy in ideal conditions and noise-limited performance in realistic settings.
- Demonstrates equivalent accuracy to iterative methods with a 484× reduction in computation time.
- Provides a sensitivity analysis for practical system integration guidelines.
Conclusions:
- Accurate, real-time harmonic estimation from single-cycle data is achievable with fixed-rate acquisition.
- The proposed method enables improved monitoring and protection capabilities in modern power systems.
- Facilitates enhanced power quality analysis without system modifications.
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