The motivation to improve components in electric power equipment brings new proposals from world-renowned scientists to strengthen them in operation. An essential part of every electric power equipment is its insulation system, which must have the best possible parameters. The current problem with mineral oil replacement is investigating and testing other alternative electrical insulating liquids. In this paper, we present a comparison of mineral and hydrocarbon oil (liquefied gas) in terms of conductivity and relaxation mechanisms in the complex plane of the Cole-Cole diagram and dielectric losses. We perform the comparison using the method of dielectric relaxation spectroscopy in the frequency domain at different intensities of the time-varying electric field 0.5 kV/m, 5 kV/m, and 50 kV/m. With the increasing intensity of the time-varying electric field, there is a better approximation of the Debye behavior in all captured polarization processes of the investigated oils. By comparing the distribution of relaxation times, mineral oil shows closer characteristics to Debye relaxation. From the point of view of dielectric losses at the main frequency, hydrocarbon oil achieves better dielectric properties at all applied intensities of the time-varying electric field, which is very important for practical use.

Improving the dielectric properties of liquid-insulating materials is a current problem in research into the insulation system of a power transformer. Modern optimization of insulating liquids involves the potential use of unique synthetic esters enriched with nanoparticles. This study presents the results of the dielectric response of liquefied gas-based (GTL) insulating liquids during accelerated thermal aging. The dielectric relaxation spectroscopy method was used in the frequency domain to point out power losses as an imaginary part of a complex electric modulus. The relaxation spectra express the validity of applying this complex dielectric parameter. The polarization processes of the base oil alternately change position in the low-frequency band during thermal aging. Fullerene nanofluid undergoes three phases of dielectric loss changes during thermal aging. In the case of magnetic nanofluid, the effect of electric double-layer polarization disappeared after 500 h of thermal aging. It was found that with the gradual increase in the thermal aging time, there is no gradual increase in the dielectric losses investigated in the measured frequency spectrum. This study shows that the concentration of the two types of nanoparticles independently causes a different dielectric response to an applied AC electric field in the GTL base fluid.

The article deals with introduction to electric vehicle 2 grid operation in smart grids from view of contribution of these devices (chargers) to smart grid as a battery energy storage systems. In the beginning of article is described overview of charging technologies and potential influence to distribution grid. The whole topic is described on the experiment (simulation) of a distribution network with connected nanogrids consisting from renewable resources, usual residential load and vehicle 2 grid DC chargers.

The article deals with the description of various modes of connection of electric vehicles to the grid, taking into account the operation of these vehicles in the vehicle-to-grid mode. The simulation of a simple microgrid network, which includes residential electricity consumption and photovoltaic power plants as renewable energy sources, illustrates the charging and discharging modes of the grid. Three scenarios were selected for the study, which are described by the number of connected vehicles and their mode. The result of the simulation is the evaluation of the contribution of these connected vehicles to the overall power balance at the interface of the distribution network and the microgrid network.

The paper deals with the electric vehicle (EV) charging challenges amidst electromobility's expansion, highlighting different charging techniques and power control strategies essential for global adoption. It evaluates the effects of charging through simulations in the Technical University of Košice's Electrical Engineering lab, investigating both private and public charging scenarios. The analysis aims to guide future charging infrastructure projects, drawing on practical experiences and consultations with industry experts. Insights gained from the Smart Industry Lab, including access to advanced measuring equipment and software, underscore the study's contributions to understanding EV charging dynamics and its feedback effects on the electrical grid.