The neutral wire in most power flow software is usually merged into phase wires using Kron's reduction. Since the neutral wire and the ground are not explicitly represented, neutral wire and ground currents and voltages remain unknown. In some applications, like power quality and safety analyses, loss analysis, etc., knowing the neutral wire and ground currents and voltages could be of special interest. In this paper, a general power flow algorithm for three-phase four-wire radial distribution networks, considering neutral grounding, based on backwardforward technique, is proposed. In this novel use of the technique, both the neutral wire and ground are explicitly represented. A problem of three-phase distribution system with earth return, as a special case of a four-wire network, is also elucidated. Results obtained from several case studies using medium and low voltage test feeders with unbalanced load, are presented and discussed.

The problems of wave propagation and power flow in the distribution network composed of an overhead wire parallel to the surface of the ground have not been satisfactorily solved. While a complete solution of the actual problem is impossible, as it is explained in the famous Carson's paper (1926), the solution of the problem, where the actual earth is replaced by a plane homogenous semi-infinite solid, is of considerable interest. In this paper, a power flow algorithm in distribution networks with earth return, based on backwardforward technique, is discussed. In this novel use of the technique, the ground is explicitly represented. In additon, an iterative method for determining impedance for modelling ground effect in the extended power flow algorithm is suggested. Results obtained from single-wire and three-wire studies using IEEE test networks are presented and discussed.

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The purpose of this paper was to determine whether the Covid-19 Pandemic influenced the change in the extent of online shopping of organic food in Serbia and whether it has led to a change in organic food consumer behaviour. The survey was carried out in Serbia by using a questionnaire developed specifically for this purpose. The total sample size included 1022 respondents of which 90 respondents were online buying organic food during Covid-19 Pandemic. Descriptive statistics and Chi-square test were used to analyse data obtained from the survey. The results indicate that the Covid-19 Pandemic influenced the increase in the percentage of consumers who purchase organic food online. Also, the changes in the type and volume of organic food consumption were identified. Besides, the consumption of organic food varied in relation to the sociodemographic characteristics of consumers who purchased online.

In this paper, a fuzzy algorithm for integrated state estimation and load flow analysis in the distribution networks is presented. The algorithm uses an available set of historical data and real-time measurements. The influence of historical data and participation of consumer categories in the node load, as well as influence of real-time measurements on the load estimation, are linguistically described using fuzzy set notation. The corrective fuzzy estimation for minimization of uncertainty fuzzy variables is based on available real-time measurements. Fuzzy solutions can be used directly, as input data for other distribution management system (DMS) fuzzy applications, or indirectly, in the classical algorithms (after the defuzzification is performed). The results and practical aspects of the proposed methodology application on two characteristic real-life distribution networks are presented.