The fundamental component synchrophasors are widely used nowadays, based on the use of phasor measurement units (PMUs), in several applications in electrical power systems. For the advancement of monitoring technology, harmonic synchrophasor estimation is still a challenge. To make it possible, it is necessary to correctly estimate the harmonic phasor (magnitude and phase of each harmonic component), mainly in scenarios with frequency deviations and noise. In this context, this present article proposes the use of B-spline-based interpolation as a preprocessing algorithm for the discrete Fourier transform (DFT). The performance is evaluated in terms of total vector error (TVE) considering the tests proposed by the IEEE C37.118.1 and IEC 60255-118-1 standards and compared with four different harmonic phasor estimation (HPE) methods, the HPE, sinc interpolation function-based estimator (SIFE), Taylor–Fourier transform (TFT), and flat-top finite impulse response (FT FIR). The proposed method can provide a TVE below 1% for all harmonic phasors, from the first to the fiftieth order, under significant frequency deviation. Also, for real-time validation, the proposed method was implemented in an industrial computer as a software routine capable of processing the signals in real time. The signals are acquired by a commercial merging unit (MU) and the samples are published using the IEC 61850 sampled values (SVs) protocol.

The current scenario of electric power systems expansion requires the insertion of new devices and technologies, contributing to the establishment of smart grids. However, the more instruments are connected to the grid, the greater the amount of data resulting from the measurements, which can cause a bottleneck in data transferring. The present article addresses this problem by proposing a system that implements a novel and efficient real-time data compression method based on the power signal spectral content variation, focused on long-term gapless oscillographic analysis. This system also provides a high-fidelity reconstruction for full oscillography power quality analysis. Comparison results with synthetic and real signals using another gapless power quality disturbance recorder present in literature and a commercial power quality disturbance recorder show that the proposed technique is capable to achieve a compression rate more than ten times greater than both while providing a better reconstruction quality, reaching compression ratio values of up to 10780:1 for synthetic signals and 9470:1 for real signals.

Supraharmonic (SH) disturbances are generated mainly by power electronics whose usage has increased significantly in the last decades. Consequently, supraharmonics have increased as well. The SH frequency range from 2 kHz to 150 kHz still lacks a normative measurement method. Compatibility levels and emission limits of SH are commonly presented as quasi-peak (QP) detector values for a bandwidth (BW) of 200 Hz measured by CISPR 16 receivers. In this context, this paper proposes an optimized method emulating the CISPR 16 receiver with QP detector for measuring grid disturbance levels. It makes innovative use of PLL (Phase-Locked Loop) units for estimating the highest distortion levels in the SH frequency range of the test signal, and in sequence, the QP detector with the appropriate specifications in the CISPR 16 standard is applied. Different cases of both synthetic and real signals were applied to the proposed method, which showed to be efficient in evaluating SH levels for current and voltage signals. An analysis of maximum permissible distortion levels is performed considering an individual SH distortion. In addition, the proposed method presents a computational cost reduction of approximately 91% in relation to the CISPR 16 method considering a specific case of signal containing SH distortions used for power quality analysis.

This paper presents a novel methodology to estimate the harmonic transfer impedances in electric power systems with multiple harmonic sources (HSs). The purpose is to determine the responsibility of each HS for the total harmonic distortion at a specific bus within the system, addressing a critical issue in the power quality field. To achieve this objective, it is necessary to estimate not only the individual HS, but also the transfer impedances between each source and the bus under analysis (BUA). Most methods for solving this problem are based on proper network modeling or restrict variations in harmonic sources to a single source at a time. The proposed methodology has overcome this limitation. For this, synchronized current and voltage phasors are measured at the BUA. Once the measurements are gathered, the Independent Component Analysis (ICA) method is applied to estimate the Norton equivalent. The harmonic transfer impedance (HTI) is then determined using the information provided by the ICA. To enhance the accuracy of HTI estimation, three procedures are employed for data mining the parameters provided by ICA over time to generate a well-conditioned system. Once the HTI is satisfactorily determined, the individual harmonic contributions (IHCs), i.e., the harmonic responsibility, can be estimated accurately. The effectiveness and performance of the method are demonstrated based on computational simulations using distribution and transmission systems. Additionally, the methodology is validated with real data collected from a Brazilian transmission system monitored by synchronized power quality measurement units. Simulated results show that the Total Vector Error (TVE) is less than 0.4%, and for the field data test, the TVE is less than 2%.