Measurement of IEC Groups and Subgroups using Advanced Spectrum Estimation Methods

Abstract

Abstract-The International Electrotechnical Commission (IEC) standards characterize the waveform distortions in power systems with the amplitudes of harmonic and interharmonic groups and subgroups. These groups/subgroups utilize the waveform spectral components obtained from a fixed frequencyresolution discrete Fourier transform (DFT). Using the IEC standards allows for a compromise among the different goals, such as the needs for accuracy, simplification, and unification. In some cases, however, the power-system waveforms are characterized by spectral components that the DFT cannot capture with enough accuracy due to the fixed frequency resolution and/or the spectral leakage phenomenon. This paper investigates the possibility of a group/subgroup evaluation using the following advanced spectrum estimation methods: adaptive Prony, estimation of signal parameters via rotational invariance techniques, and root MUltiple-SIgnal Classification (MUSIC). These adaptive methods use variable lengths of time windows of analysis to ensure the best fit of the waveforms; they are not characterized by the fixed frequency resolution and do not suffer from the spectral leakage phenomenon. This paper also presents the results of the applications of these methods to three test waveforms, to current and voltage waveforms obtained from simulations of a real dc arc-furnace plant, and to waveforms measured at the point of common coupling of the low-voltage network supplying a high-performance laser printer.Index Terms-DC arc furnaces, discrete Fourier transform (DFT), estimation of signal parameters via the rotational invariance techniques (ESPRIT) method, Prony method, root MUltipleSIgnal Classification (MUSIC) method, spectrum estimation, subspace methods, waveform-distortion analysis.

Harmonic and interharmonic currents generated by the VSI-fed adjustable speed drive

“…ω s is always far higher than ω r , so we calculate with the harmonic component of kω r . The relationship of the currents and voltages are showed as below (8) The switching function of three-phase ac/dc diode-bridge rectifier is shown as (9) , in which k=2 /π, ω=2πf. f is the foundation frequency of the supply system.…”

“…1. Though the VSI-fed ASD acts like a workhorse for many industrial applications, it generates significant amount of harmonic and interharmonic currents into the power system during the switching process [7]- [9]. These distorted currents then cause some undesired effects on power system components and loads, such as overheating, resonance, power line carrier signal interference, and induce visual flicker in display devices.…”

Impact of signal attributes on autocorrelation matrix dimension for smart grid solutions

“…Signal processing is becoming integral part of the modern power system analysis as evident from some of the ample Sachin literature in this field of the recent past [3]- [8], [11]- [15], [20]- [23], [27]- [37]. All of the mentioned areas utilize the signal processing tools in some or other forms.…”

“…are gaining more popularity, owing to their high frequency resolution and tolerance for fundamental frequency deviation. Some of the recent literature on parametric methods application to the power system includes: [29]- [30] for transient analysis, [31] for fault location estimation, [22] and [23] for islanding detection, [32] and [33] for analysis of low frequency oscillations, [11], [34]- [37] for harmonics estimation, etc.…”

Using windowed ESPRIT spectral estimation for measuring power quality indices

“…There have been recent publications on the use of modern spectral estimation techniques for detecting power quality events such as estimating the harmonics and inter-harmonics [15] [16] and also the measurement of the respective amplitudes as in [16] [17], however none of these publications have calculated the power quality indices as outlined in the IEEE std 1459-2010. This paper provides a new approach to the calculation of the power quality indices as outlined in the IEEE 1459-2010 standard.…”