Bozo Krstajic

Smart grid data analytics for digital protective relay event recordings

Information systems and intelligent smart grid data analytics will have a critical role in managing the massive amount of data becoming available in power system substations. Digital protective relays are multi-functional intelligent electronic devices based on microprocessors, which are being installed in substations throughout the power grid. New digital relays are replacing old-fashioned electro-mechanical or solid-state relays, and besides their protective function, they are coming equipped with monitoring capabilities. These monitoring capabilities are creating potential for better observability of power systems, redundancy in measurements, and improved decision-making process when operating the system. This article discusses the implementation requirements for a fully automated data analytics solution that provides data integration, fault analysis, and visualization based on the event data recorded by digital protective relays.

Improved Frequency Estimation in Unbalanced Three-Phase Power System Using Coupled Orthogonal Constant Modulus Algorithm

A new iterative method for frequency estimation in the unbalanced three-phase power system is proposed. The proposed solution is based on the transformation of unbalanced three-phase voltage signal into a complex exponential by using the orthogonal constant modulus algorithm. In addition, based on the transformed signal, a simple adaptive algorithm for frequency estimation is proposed. Beside the proposed approach, any frequency estimator designed for a single-tone complex exponential can be used here, which is also the advantage of the proposed method. Simulation results confirm that the proposed algorithm exhibits better performance compared to the considered algorithms.

Frequency-domain adaptive algorithm for improving the active noise control performance

A new block adaptive algorithm for active noise control systems is proposed. The proposed approach uses two adaptive filters, where the first one is used for identification of the unknown system. The second one is adapted using the coefficient of the first filter, with the purpose to minimise the output error. To reduce the computational complexity, implementation of new algorithm in the frequency domain is proposed. The analysis of this approach and simulation results show that the new algorithm exhibits faster convergence speed and smaller steady-state error, as compared with the filtered-x least mean square and its modifications.

Adaptive channel equalizer with new VSS LMS algorithm

This paper introduces a new variable step-size LMS (NVSS LMS) algorithm in an adaptive channel equalizer. This variant of VSS LMS algorithm is based on the weighting coefficients bias/variance trade-off. We will show here that the adaptive equalizer with the NVSS LMS algorithm has favorable performance. Simulation results are provided to support the proposed implementation of the NVSS LMS.

Verification of the three-dimensional structure of synthesized molecule by molecular dynamic simulations

The paper presents comparison between molecular models made by using software packages, experimental results and performed simulations in molecular dynamics area with created molecule. Molecule was synthetized using organic synthesis strategy. After structural analysis, precise layout of all the atoms in space was determined. Molecule was converted into standard chemical format, visualized and prepared for simulations. Here we intend to show that it is possible, by using powerful computer infrastructure and related applications, to create good models of molecules, which can be used in simulations that produce valid characteristics of subject molecules interacting with various organic compounds.

pyPMU — Open source python package for synchrophasor data transfer

pyPMU is an open source Python package library that implements the IEEE C37.118 standard protocol for synchrophasor data transfer. Synchrophasor measurements provide a precise and time-synchronized phasor measurements collected throughout power grid. The pyPMU library offers various functions for supporting synchrophasor applications and it enables rapid synchrophasor test bed implementations. The paper provides detailed overview of the pyPMU package, its installation, and usage examples. The most interesting use scenarios include PMU simulator and PMU data stream splitter, which have been described in the paper. The discussion illustrates initial benchmarking results and current issues. Finally, the paper outlines future work on the improvements and practical applications. The pyPMU project is published under 3-clause BSD license and made available at GitHub.

Increasing the convergence speed of FxLMS algorithm in terms of white noise

Here we propose a modification of the FxLMS algorithm aimed to increase the convergence speed in terms of white noise. Secondary path distorts diagonality of autocorrelation matrix of white noise which causes a slower convergence of the FxLMS algorithm. Using information about the coefficients of the impulse response of secondary path, we propose the way to reduce the impact of secondary path and diagonalize the autocorrelation matrix. The simulation results confirm theoretical considerations in this paper.

Adaptive Noise Cancelling with a New VS LMS Algorithm

Abstract This paper proposes an adaptive system for noise-cancelling for signals corrupted by additive white noise. The proposed system is based on the new Variable Step LMS algorithm. We have taken the ratio between bias and variance of the weighting coefficients as the main criteria for estimation of the LMS algorithm step size. The paper presents comparative analysis of the proposed algorithm and LMS algorithm, used in this application. Presented comparative results of the considered adaptive systems verifY the analytical solution and advantages of the proposed algorithm.