Power Quality Monitoring System for Electrical Networks

Abstract

Ensuring the quality of electricity is one of the ways to increase the efficiency of the entire energy complex of Ukraine and its individual energy systems. At the same time, it is necessary to note the following. Analysis of the current state of Ukraine’s electricity industry shows that its current integration with the electricity sector of the EU requires compliance with the necessary conditions for compliance with strict requirements for electricity quality parameters, which must be within acceptable levels set in a number of regulations. It should be noted the following. The development of measures to ensure the required quality of electricity is possible only after assessing its actual state in all nodes of the country’s electricity system. Therefore, the system of real-time monitoring of electricity quality should be based on real-time monitoring system. This study considers the model of information flow in the electrical network, which is a hierarchical structure of comparative, frequency calculation of local maxima of wavelet transform coefficients with time shift, adaptive to the singular behavior of the signal. This model allows from a single mathematical standpoint based on the analysis of frequency-time and spectral characteristics of comparative wavelet coefficients to conduct the full range of data processing on power consumption modes, definition, identification and classification of distortions of electricity quality. Based on the analysis of the detailed coefficients of the wavelet composition, a generalized identifier of the distortion of the quality of electric energy is presented, which serves as a basis for the express analysis of the quality of electric energy in real time. Its application allows, regardless of the type of distortion, its direct detection, beginning and/or end. Further identification of the type of distortion and its classification is carried out using the developed modified vector of features of the classification of distortions of electricity quality. Whereas, as a result of wavelet decomposition of the information signal and analysis of the obtained wavelet coefficients, time-localized information on its distortion (deviation from the nominal values of its parameters) from the high- and low-frequency ranges is obtained, therefore, the frequency-energy properties of these coefficients are the basis of the method of classification of distortions in the quality of electrical energy. The presented approach to the formation of the system of monitoring the quality of electricity, in contrast to the existing approaches in which sequential processing of the measurement signal to determine individual indicators of quality of electricity, allows building a system of monitoring the quality of electricity in real time.