Electricity

Technological and Intelligent-Digital Innovations as the Basic Principles of Electric Power System Transformations

2025-09-17T16:31:46+00:00

The article provides a comprehensive analysis of technological and intelligent-digital innovations in the electric power systems in Russia and around the world. The electric power industry sectors (generation, storage and transmission of electricity, and control systems), modernization of existing equipment, and introduction of innovative technologies are considered. It is noted that large power generating sources, including conventional (nuclear, thermal, and hydroelectric power plants) and new ones (mainly based on renewable energy resources), and small-scale generation plants (microturbines, gas piston plants, small renewable energy sources, and others) are actively developed. The transition from conventional pumped storage power plants to new electricity storage technologies, including electrochemical and others, is underway. Energy storage facilities are used both in power systems and locally. In electrical networks, technological progress leads to the use of higher voltage levels and growth of transmission capacities, and to the construction of low-voltage microgrids (connecting consumers, small-scale generation and electricity storage installations), including DC ones. Active implementation of intelligent digital solutions in the electric power industry is underway, which entails the occurrence of numerous control entities. It is summarized that the mentioned innovative processes result in that the modern electric power systems are transformed into complex and efficient multi-subject cyberphysical power systems with a combined centralized and distributed structure and with an expanded energy resource base.

Evolution of Substation Switchgear Circuit Diagrams

2025-09-17T16:55:43+00:00

The evolution the switchgear circuit diagrams of high voltage substations have passed from the beginning of the last century to nowadays is analyzed. The influence of trends in the development of electrical apparatuses, power grids and power systems as a whole on the topological and operational features of the circuit diagrams is shown. Characteristic time stages of circuit diagram standardization are identified along with cause-and-effect relationships regarding changes in the corresponding technical solutions. The first stage was characterized by the unchallenged dominance of a circuit diagram with double busbars, with one busbar system being the main one and the other the standby one (from early 20th century to the late 1940s). The second stage was marked by the widespread adoption of transfer busbar for this circuit diagram and the transition to fixed connections (from the late 1940s to the late 1960s). The third stage was characterized by the introduction of ring circuit diagrams for large power plants and substations in the 330-500 kV backbone electrical networks (from the second half of the 1960s and early 1970s until the end of the 20th century). The fourth (current) stage is associated with the widespread use of SF6 CBs, which have simplified the circuit diagrams while reducing their uniformity due to an excessive increase in the number of circuit diagrams. The results of a multifactor analysis of the current set of typical alternative circuit diagrams of substation switchgears are presented, taking into account aspects of reliability, cost-effectiveness, convenience of operation, environmental friendliness, and compactness. The advisability of deeply unifying a number of circuit diagrams is proven, including the selection of the most preferred solutions. It is recommended to expand the application areas of ring circuit diagrams to high voltage electrical installations of all voltage classes.

Balancing the Normal Mode in Four-Wire Three-Phase Extra-High Voltage Lines

2025-09-17T17:06:41+00:00

Conventional single-circuit extra-high voltage AC power lines, widely used all over the world, feature an essential drawback: in the case of sustained single-phase faults, which are most likely to occur on such line, the latter is disconnected completely. The article considers a four-wire three-phase line, one phase of which is implemented as two half-phases. In emergency operation modes, any of the half-phases is used as a backup phase, and in the middle part of the other phases, series compensation devices are connected for balancing the operation mode and increasing the transmission capacity. The four-wire three-phase line features increased reliability owing to the fact that in the post-emergency it can shifted to operate with the possibility to transfer at least 50% of the initial maximum power in case of sustained faults. Series compensation devices that eliminate series imbalance can be installed not only in the middle part of the line, but also at its ends. Controlled shunt reactors, which reduce transverse imbalance, are placed at the ends of the semi-phases. The task of balancing the normal mode is to determine the parameters of the balancing devices, i.e., series compensation devices and controlled shunt reactors, depending on the length of the four-wire three-phase line and its design features. An algorithm has been developed, using which one can find the parameters of balancing devices that will keep the imbalance degree within acceptable limits. In application to a four-wire three-phase 500 kV line of a given design, simple relations are proposed for calculating the parameters of the balancing elements depending on the line length.

Mathematical Modeling of the Skin Effect in ACSR Wires

2025-09-17T17:18:51+00:00

In overhead power lines made of aluminum conductor steel reinforced (ACSR) wires, part of active power loss is due to the higher harmonic current components. This is manifested in that the current sinusoidal waveform is distorted, and the current is displaced to the conductor surface with increasing the frequency (a skin effect). At the same time, increasing the frequency in electrical and autonomous power supply systems (for example, up to 400 or 800 Hz) is advisable for the possibility to achieve significantly smaller weight and overall dimensions of the equipment, especially for mobile facilities. The article presents mathematical models and the results of finite element modeling carried out taking into account the influence of temperature on the resistance growth coefficients caused by the skin effect. A comparative analysis was carried out, which has shown the possibility of using an analytical method for determining the resistance of ACSR wires with taking into account the higher harmonic current components. Two methods for obtaining analytical characteristics of the skin effect coefficients in the power line wires are considered. It is shown that a stranded wire can be considered as an "equivalent" homogeneous (single core) wire if the steel content does not exceed 25 % of the wire total volume.

Формирование группового алгоритма дистанционного определения места повреждения воздушной ЛЭП с использованием методов машинного обучения

2025-09-17T17:47:56+00:00

The possibility of improving the accuracy of fault location on overhead power lines using machine learning techniques is analyzed. Two approaches are proposed: adaptive selection of the optimal fault location method for specific emergency conditions and weighted averaging of results using probabilistic weights. The errors of 11 one-side and 19 two-side methods were analyzed, and their weaknesses were revealed depending on various influencing factors. A training dataset was generated based on the 500 kV power line simulation results. The Time Series Forest (TSF) and Hydra Classifier models were selected for training, with TSF demonstrating higher efficiency. The model correctly identifies the optimal fault location method in 57 % of cases for one-side and 71 % for two-side methods. The use of weighted averaging made it possible to decrease the reduced fault location error: for one-side methods, the error did not exceed 2.5 % in 99 % of cases, while for two-side methods, 95 % of cases showed errors below 1 %. Comparison with conventional averaging and individual fault location methods has confirmed the advantage of machine learning in adapting to varying emergency mode conditions. All numerical results have been obtained using phasor measurement data as emergency current and voltage values. The proposed approaches are most relevant for centralized fault location systems, as they enable one to implement many fault location methods.

СВЧ-установка для нагрева компаундов

2025-09-17T18:05:22+00:00

By means of mathematical modelling, the microwave heating modes of an epoxy compound have been determined that help intensify its curing process in obtaining high-energy radio-absorbing composites. The equations of electrodynamics and heat conduction were solved using the finite element method, which was implemented in the COMSOL Multiphysics software. With such approach, it became possible to solve the equations in the 3D statement, taking into account the properties of the compound and their changes in the course of microwave heating. The article presents the results from numerical studies of temperature and electric fields distribution in epoxy compound depending on the heating modes. It has been found that a microwave chamber with waveguide-slot radiators makes it possible to obtain uniform distribution of electric field and uniform heating of epoxy compound due to distribution of specific power along the entire working chamber length. The design of a methodically acting microwave unit is proposed that ensures uniform heating of epoxy compound for intensifying its curing process in obtaining high-energy radio-absorbing composites. The unit uses a two-way power supply with connection to two microwave generators to increase the productivity and improve the product heating uniformity. The developed design of the methodically acting microwave unit with a system for automatic control of processing parameters can be applied for heating of liquid compound systems with dielectric indicators close to those of epoxy resin.

Areas of Functional States in Managing Electrical Engineering Systems

2025-09-17T18:18:44+00:00

The article presents a morphological analysis of the technical states of electrical engineering systems Based on this analysis, the areas of functional states are introduced, information about which is used to solve problems concerned with managing the state of electrical engineering systems. It is shown that there is lack of clear understanding of the most important concepts related to the “state” category in the literature. The parameters of electrical engineering systems are considered. A classification of the types of states is given, which is based on the standards currently in force. The areas of functional states are introduced for solving parametric and structural control problems aimed at ensuring the operability and survivability of electrical engineering systems. An analytical description of the operability and serviceable operation areas is obtained, which is based on applying the theory of logical R-functions, and which is invariant to the shape of the area and the dimension of the problem. Using particular examples, the application of the analytical description of the functional state areas is considered to solve the parametric and structural synthesis problems. With such an approach, the structural synthesis problem is reduced to preventive management of a ship's electric power system components that ensures survivability of the power installation and the ship as a whole.

The School of Russian Electric Power Engineering of the Peter the Great St. Petersburg Polytechnic University – 125 Years of Development from the Electromechanical Department to the Institute of Power Engineering

2025-09-17T18:28:34+00:00

The article briefly reviews the development history of the School of Electric Power Engineering and Electrical Engineering at the Peter the Great St. Petersburg Polytechnic University, from its establishment in 1899 to the present day. It provides brief historical information about the university's establishment, its organization and structure, as well as the main stages of its reorganizations, reforms, and name changes, accompanied by historical photographs. The article also includes brief biographies of graduates and employees of the SPbPU Electromechanical Division (Department). The article presents the main scientific achievements of Russia's outstanding scientists who laid down the principles of electric power engineering and developed it from the university founding to the present day. This period covers the development of electrical engineering from the GOELRO plan to the technologies of digital twins and artificial intelligence. An attempt has been made to mention, in this short article, the names of most prominent and talented researchers who have received higher education, received Doctoral or Candidate’s dissertations at SPbPU, whose scientific and pedagogical activity is connected with SPbPU, and who have been recognized by the Russian and international scientific societies, academicians, and corresponding members of the Russian Academy of Sciences.