The problem of getting rid of expensive and metal-intensive current transformers has been declared by CIGRE as strategically important for the electric power industry. However, almost all traditional current protections receive information from measuring current transformers. In this work, a resource-saving reed switch overcurrent protection without current transformers is suggested, which can be used as an alternative to traditional current protections for 6–10 kV electrical installations connected to a switchgear cell. The protection is designed following the novel method we have developed based on inductance coils. Inductance coils measure the electromotive force under different operation modes of an electrical installation and at different points inside the switchgear cell it is connected to; the EMF values are recalculated in the values of magnetic induction, and reed switches are mounted instead of inductance coils at the points where the magnetic induction is maximal. Moreover, these values are sufficient to detect phase-to-phase short circuits in the electrical installation. The dependence of the induction value on the position of an inductance coil inside the cell is derived with the use of the simplest formula of the Biot–Savart law. The results can be used at large and small industrial enterprises, electric power stations, and substations of plants; they can be interesting for the scientific community because they help to solve the topical problem of the electric power industry.

The object of research is a wind generator with counter-rotating blades. A special feature of this design is the presence of two wind wheels that rotate in opposite directions. Wind wheels are on the same axis, between them there is a certain distance, which is determined based on research data. The problem of modern wind power is the low range of operating wind speeds, weak generation at low wind speeds. The upper speed limit is 25 m/s, exceeding which leads to breakdowns of various units of the wind station, especially this affects the integrity of the blades, rupture of the wind wheel, cracking of the metal parts of the bearings and their fasteners. The wind turbine presented in the article allows to achieve an increase in the generation of electric energy by 50–70 %. This is achieved by increasing the relative rotational speed of the rotor relative to the stator. Therefore, even at low speeds, the rotor speed relative to the stator increases, which leads to an increase in power generation. The design of the device includes: two wind wheels, one transmits its rotation to the stator, the second to the rotor axis, a metal base, a current collector mechanism. For conducting the research, an experimental model and a semi-industrial installation were used. Results studies have confirmed the theoretical increase in the generation of electrical energy by this design. The peculiarity of the obtained results is connected with the determination of the distance between two wind wheels, the optimal distance between them corresponds to the maximum energy generation. A distinctive feature of the results obtained can be considered an increase in the number of blades on the second wind wheel Об’єктом дослідження є вітрогенератор із зустрічно обертовими лопатями. Особливістю такої конструкції є наявність двох вітрових коліс, які обертаються в протилежних напрямках. Вітрові колеса знаходяться на одній осі, між ними є певна відстань, яка визначається на основі даних досліджень. Проблемою сучасної вітроенергетики є низький діапазон робочих швидкостей вітру, слабка генерація при малих швидкостях вітру. Верхня межа швидкості становить 25 м/с, перевищення якої призводить до поломок різних вузлів вітрової станції, особливо це позначається на цілісності лопатей, розриві вітрового колеса, розтріскування металевих частин підшипників та їх кріплень. Представлений у статті вітрогенератор дозволяє досягти збільшення вироблення електроенергії на 50–70 %. Це досягається збільшенням відносної швидкості обертання ротора відносно статора. Тому навіть при низьких швидкостях обертання ротора відносно статора зростає, що призводить до збільшення вироблення електроенергії. У конструкцію пристрою входять: два вітрових колеса, одне передає своє обертання на статор, друге на вісь ротора, металева основа, струмоприймальний механізм. Для проведення досліджень використовували експериментальний макет і напівпромислову установку. Результати досліджень підтвердили теоретичне збільшення генерації електроенергії цією конструкцією. Особливість отриманих результатів пов'язана з визначенням відстані між двома вітровими колесами, оптимальна відстань між якими відповідає максимальному виробленню енергії. Відмінною особливістю отриманих результатів можна вважати збільшення кількості лопатей на другому вітровому колесі

The object of this research is a model of a wind turbine with retractable blades. This model allows for the adjustment of the turbine’s screw radius by extending or retracting the blades, providing a basis for examining the impact of blade radius on turbine performance. The primary problem addressed by this study is to determine how changes in the screw radius, achieved by altering the blade length, affect the wind turbine’s performance, specifically its electrical output (voltage and current) and rotational speed, under constant wind conditions. The experimental results showed that when the turbine blades are fully extended (R1), the wind turbine generates higher voltage and current compared to when the blades are retracted (R2). This confirms that the turbine’s electrical output is significantly influenced by the screw radius. These results are explained by the aerodynamic principles governing wind turbines. An increased screw radius allows the turbine blades to capture more wind energy, leading to greater force applied to the blades, thus increasing the rotational speed and the amount of electrical energy generated. The linear relationship between the screw radius and the turbine’s performance was as summed to simplify the analysis, though the actual relationship may be more complex. The finding soft its study can be practically applied in the design and operation of wind turbines. Turbines with adjust table blade lengths can optimize performance across varying wind conditions, maximizing efficiency and power output. These results are particularly useful in environments where wind speed is variable, as turbine scan adjust their blade radius to maintain optimal performance. The study assumes consistent wind conditions and uniform air flow for the results to be accurate, so these conditions should be considered when implementing the findings in real-world scenarios

The paper presents an overcurrent protection with its construction, which is an alternative to traditional current protections and has a resource-saving effect of the materials used. The development of alternative resource-saving devices of relay protection of electrical installations against faults without the use of metal-intensive measuring current transformers with iron cores was started in the 60s of the last century, which are still relevant today. Scientific novelty of the work consists in further development of the theory of construction of resource-saving protection based on measurement of magnetic field induction values inside the current-carrier. At the same time these values are sufficient to detect inter-phase faults inside it. In this protection the magnetically controlled contact acts simultaneously as a current sensor and a measuring device of protection, reacting to the magnetic field created by the currents in the current-carrying busbar of the conductor. To perceive the values of magnetic field inductions, the magnetically controlled contact is placed close to the current-carrying busbar, observing the minimum permissible distance. The aim of the research is to develop a new resource-saving protection for current-carrying busbars based on magnetically controlled contacts. At the same time in the presented protection there is a possibility of remote control of operation settings without disconnection of the current conductor itself. This paper proposes a new solution for the realization of an alternative resource-saving protection in the form of a construction for protection against faults inside the conductor.

This paper presents the development and principle of operation of resource-saving overcurrent protection, which is an alternative to traditional current protections. The experiments were used to study the electromagnetic field for the protection of electrical installations connected to the cells of complete switchgears, voltage 6–10 kV, without the use of conventional protections with metal-core current transformers. As is known, such current transformers (CTs) have significant weight and dimensional parameters and high price costs. The method of research is comparison of the developed protection with traditional current protections made using traditional measuring current transformers. The scientific novelty of this work consists of the developmental theory of the construction of protection for inductive coils based on the measurement of electromotive force values in different modes and points in the simulation of a three-phase short circuit inside the cell of the complete switchgear. The dependence of magnetic induction on the position of the inductive coil inside the cell has been found. It has been shown that the simplest formula of the Biot–Savart–Laplace law can be used to calculate them. This paper presents and describes the conducted experiments with their methodology. As a result of the industrial application of such protections, the act of implementation of the patent for the invention of an industrial enterprise is presented. The selection of settings of resource-saving protection is presented, as well as a feasibility study of the presented protection in comparison with conventional protection. This paper consists of the following sections: The Materials and Methods section describes the methodology used to achieve the purpose of the research. The Experiments section describes all the experiments conducted to achieve the purpose of the research. The Results section presents the results of the conducted experiments, an evaluation of the use of inductive coils in relay protection, an example of calculating the selection of the settings of parameters of resource-saving protection, a presentation of the patent for the invention, and a presentation of the feasibility study of the effectiveness of the considered resource-saving protection on inductive coils. The Conclusions section presents the result of this work, which is the creation of resource-saving protection on inductance coils. The References section presents a list of the sources used.