The object of this research is the process of water disinfection by means of high-frequency electrical discharge. The study addresses the problem of achieving high biological efficiency while reducing energy consumption and avoiding harmful by-products typical of traditional methods such as chlorination or UV irradiation. As a result, a comprehensive theoretical and experimental investigation was conducted, demonstrating that within 20 s of plasma exposure, E. coli, S. aureus, and P. aeruginosa bacteria were inactivated by 99.2–99.9%. The observed efficiency is explained by the synergistic action of reactive oxygen and nitrogen species (•OH, O₃, H₂O₂, NO₂⁻, NO₃⁻) formed in the plasma–water interface. The distinctive features of the obtained results include the establishment of optimal operating parameters-voltage U = 12–18 kV, frequency f ≈ 35 kHz, and gap distance d = 15 mm—under which the normalized specific energy input (SEI) was 6–9 kWh per cubic meter of water. This value represents the standard normalization used for plasma-based treatment systems, where the electrical energy delivered to the reactor is divided by the treated volume (1.0 L in our setup) and scaled to m³ for comparison with other studies, 30–40% lower than in previously reported plasma systems. The validated physicochemical model (Poisson, Navier–Stokes, and continuity equations) matched experimental data with R² ≥ 0.95, confirming its predictive capability for further scale-up. The practical significance of the results lies in the potential application of this method for decentralized and industrial water treatment systems. The reagent-free, energy-efficient, and environmentally safe nature of the proposed approach makes it suitable for sustainable water purification under real operating conditions.

A range criterion of discounted costs is proposed, which takes into account all costs for a speed-controlled asynchronous electric drive, including its price, costs of losses and maintenance, and amortization charges. It is also possible to take into account the cost and energy performance of matching transformers and gearboxes. Costs for reactive power compensation of both the first and second kind (due to the presence of harmonic components at the drive input) are taken into account. The latter requires determining the total harmonic distortion (THD) of the currents consumed by the drive. In the case of autonomous power systems, it is also necessary to determine the drive’s supplying voltage non-linear distortion coefficients. Representing the discounted costs as the sum of initial capital investments and annual costs made possible taking into account the presence of inflationary processes. The control characteristics of the active power consumed by the drive, efficiency, power factor, and phase shift factor are constructed, which are dependencies on the rotation frequency in a certain control range at a specific load. It is proposed to calculate the drive’s discounted costs criterion, depending on the operating mode of the load. According to the mode, the criterion is calculated as an average range in a certain range of speed control or is determined taking into account a given tachogram of speed changes. For the controlled asynchronous drive under consideration, the discounted costs are 4148 c.u. in the first case and 5139.3 c.u. in the second case. If inflationary processes are taken into account, the first case is 4219.4 c.u. and the second case is 5227.7 c.u., respectively.

The article is devoted to the energy transformation in Kazakhstan, focusing on the need to switch to sustainable energy sources in the face of growing electricity consumption and environmental problems associated with dependence on coal-fired power. The text examines global trends such as reducing carbon emissions and the transition to renewable energy sources, as well as the role of Kazakhstan in these processes. The article analyzes the current problems of the country’s energy infrastructure, including the high level of deterioration of heating networks and the need for modernization, as well as discusses the prospects and challenges of developing green technologies such as solar, wind and biomass energy. Special attention is paid to financial support for renewable energy projects, as well as opportunities for the country to improve the environmental situation and economic growth through the introduction of innovative technologies. In conclusion, the importance of further efforts to develop infrastructure, train specialists and attract investments to achieve a sustainable energy future for Kazakhstan is emphasized. Keywords: Renewable energy sources, energy transformation, green technologies, solar energy, wind power plants.

The design of special induction motors for variable-speed drives in pumping systems is carried out using the Design of induction machines for adjustable-speed drives (DIMASDrive 2022) software, based on the motor efficiency criterion. The quality of a variable-speed drive is fully determined by an innovative criterion of equivalent costs, which takes into account not only the cost and energy efficiency of the drive, but also the costs of compensating for reactive power and distortion power, which characterize the drive’s energy and electromagnetic compatibility with the grid. The MATLAB program enables the calculation of the innovative criterion of the drive’s reduced costs. Currently, the cost component of distortion power compensation is not taken into account in the reduced cost criterion; consequently, the quality of the drive in monetary terms is determined incompletely and is underestimated. A method is proposed for calculating this component and incorporating it into the reduced cost criterion. The presented results were obtained entirely through simulations conducted using validated software. Experimental studies of the prototype will provide the final answer regarding the solution.

This article examines the potential of Internet of Things (IoT) technologies in the electric power industry in the context of Smart Grid development. The study aims to quantify the economic and environmental effectiveness of implementing IoT solutions, as well as to analyze their social impact on improving electricity supply reliability, reducing operating costs, and integrating renewable energy sources (RES). The study focuses on medium- and low-voltage distribution networks, including smart meters (AMI), feeder sensors, fault-level information recovery (FLISR) systems, and demand response (DR) services. The study methodology is based on performance assessment models (NPV, IRR, TCO, payback period), difference-in-differences, and the IPMVP Option C standard for measurement verification. ISO 14064-1 and GHG Protocol emissions calculations were used to assess the environmental impact. A numerical example is provided for a medium-sized distribution company with 50,000 smart meters. The study's results demonstrate that IoT implementation can achieve a cumulative economic benefit of over 600 million tenge per year for a base of 300,000 consumers, improve electricity supply reliability, and enhance customer service. The environmental impact is reflected in a significant reduction in CO₂ emissions, while the social impact includes shorter outage durations, increased metering transparency, and increased end-user trust. The practical significance of this study lies in developing a reproducible assessment model applicable to investment planning, tariff regulation, and ESG reporting. Thus, IoT-based network digitalization confirms its economic and environmental feasibility and should be considered a strategic direction for the long-term modernization of the electric power sector.

The object of the study is a three-phase frequency converter (FC) with an uncontrolled rectifier and pulse-width modulation (PWM) of the output voltage, used for frequency regulation of asynchronous motors (AM). The problem to be solved is the improve the energy efficiency of the electric drive and the accuracy of speed control while reducing harmonic distortions of voltage and current, which is especially important for industrial installations operating in continuous or alternating mode. In the work in the Mathcad environment, a mathematical model of the FC was developed, including a power circuit, an algorithm for generating PWM and dependencies for calculating the power factor, efficiency and total harmonic distortion (THD). The model allows performing parametric studies of the effect of frequency and amplitude of the output voltage on the energy indicators of the drive with a high degree of detail. The simulation results showed that the optimized sinusoidal PWM algorithm with ordered switching distribution reduces THD by 18–22% and increases the power factor to 0.94–0.96 due to a more uniform harmonic spectrum distribution and reduced reactive losses. The advantage of the proposed model is the ability to adapt to various AM operating modes and load conditions without changing the structure of the power section, which expands its practical application. The obtained results can be used in the design and modernization of industrial electric drive systems, pump and fan units, as well as in automated complexes where economical, reliable and high-precision speed control is required. It further enables sensitivity checks and controller tuning to evaluate PWM strategies under realistic limit