This paper deals with the issues of computation of the nonlinear load harmonic currents in the presence of external distortions based on the real measurements with help of passive harmonic. Such values are necessary when modeling an equivalent nonlinear load as current sources in the presence of external distortions. The passive filter allows to separate external and internal distortions, which is necessary when determining the harmonic currents of a single consumer. The influence of various parameters on the computation of harmonic currents of a nonlinear load, such as the parameters of a passive harmonic filter, the impedance of the power supply transformer, the load parameters of the consumer, taking into account the harmonic generation from the grid side, and from the consumer side, is considered. It is shown that an external source of distortion has practically no effect on the error in estimating the harmonic current magnitudes of a nonlinear load. The obtained simulation results were confirmed experimentally on a laboratory test bench. Recommendations for the selection of passive harmonic filter parameters have been developed to minimize the error in determining the harmonic current magnitudes of a nonlinear load.

The article is dedicated to the important task of detection and elimination of liquid hydrocarbon leak in oil pipelines. The technological, regulatory and geographical aspects of the use of existing oil leakage detection systems (LDSs) and pipeline stop valves drive control systems are considered. The authors have proposed a new solution for autonomous power supply of oil LDS and stop valve drive control systems for pipelines located in inaccessible areas. The proposed autonomous power supply complex is based on thermoelectric generation units. The composition and parametric sufficiency of the autonomous complex is substantiated. The authors have developed the laboratory test bench, which verified the technical characteristics of the complex. The authors have substantiated the possibility of various designs for application of such complexes in existing pipelines.

Photovoltaic (PV) water-supply pumping is an established and cost-effective solution for autonomous water supply in rural areas. However, recent studies typically treat the borehole water level as a fixed boundary condition, evaluate designs against a typical meteorological year, and rarely account for component degradation or extreme-year weather stress over the project lifetime. This study proposes a multi-objective sizing and operation framework for an autonomous bifacial photovoltaic (bPV) water-supply pumping system, coupling dynamic borehole hydraulics, battery and water storage, and component degradation within a consistent evaluation chain from optimization through life-cycle post-verification. The non-dominated sorting genetic algorithm III (NSGA-III) drives the optimization loop, typical and extreme meteorological-year scenarios screen water-service reliability, and, following life-cycle post-verification, the VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) procedure with hybrid analytic hierarchy process (AHP)–entropy weights and Monte Carlo testing of the criterion weights selects the final compromise design. In the reference workflow, the NSGA-III run comprised 6480 objective-function evaluations; subsequent typical-year, extreme-year, and life-cycle screening retained 100 feasible designs; the selected configuration achieved a levelized cost of water of 0.0675 USD/m³, a specific energy consumption of 0.238 kWh/m³, and an aggregate life-cycle water-shortage percentage of 0.204%. The results show that dynamic-head representation and life-cycle screening materially affect the selected capacity–cost–reliability trade-off and the post-verified feasible set, providing a reproducible basis for autonomous rural water-supply design.