Mikhail V. Yaroslavtsev

The growing number of electricity consumers and unstable generation by renewable energy sources (RESs) decrease the efficiency of traditional techniques for modeling large power systems. The diakoptics method is based on structuring a system into subsystems and enables reducing the amount of computation by 2.9 times. However, its classical implementations require successive (iterative) expansion of a scheme, which increases computational time for scaling. This method decomposes a complex system into interacting subsystems with different generation and load characteristics. Generalized parameters are independently calculated for each subsystem and then integrated into the total solution. This significantly reduces the amount of computation, simplifies simulation, optimizes control with allowance for local characteristics, and analyzes intersystem connections to minimize losses and improve stability. This paper suggests not just another Kron calculation but a modification of the diakoptics method, which enables avoiding multiple step-by-step redesigns of a grid by generating generalized parameters based on the complete graph of a system, which significantly reduces computational costs when analyzing large power systems. The method simultaneously considers the entire grid topology. This eliminates successive iterations: if a classical approach requires 13 iterations for a network with 11 nodes and 21 branches, the suggested method performs computation in a single computational cycle. The results show high computational efficiency and practical applicability of the method for large power systems. The suggested approach opens up possibilities for reliability analysis, including redundancy assessment and identification of vulnerable elements, which contributes to an increase in the power system stability under conditions of RES integration.

As the cost of traction lithium batteries decreases, many rolling stock models are being created that use them to receive recovery energy, equalise the load on the energy source, and ensure autonomous operation. The objective of the work is to show the advantages of separate design and production of onboard traction storage devices and the rolling stock using them, which will require standardisation of energy storage devices, as well as to outline the range of requirements that will need to be set when developing a standard, and to illustrate proposals by identifying possible requirements for weight, size and energy characteristics of a unified energy storage device. For this purpose, a review of approaches to the use of energy storage devices and modern designs of rolling stock on which traction batteries are used is followed by main scenarios for the use there-of. Following identification of main processes of energy conversion by the traction drive of locomotives at various time intervals, the parameters of energy storage devices were assessed for a wide range of possible scenarios for their application using methods of traction theory. The results obtained allowed calculating main characteristics of unified energy storage modules. A specific analysis was carried out to identify the limitations that determine energy intensity and power, weight, dimensions and method of mounting of storage devices, their rated voltage. Requirements are formulated for design of a standard mechanical, electrical and information interface of the proposed modules.

Various modes of city passenger transport are being analyzed in the paper. The ecological efficiency of transport based on CO₂ emissions data for vehicles consuming various types of fuel is investigated. An automated calculation algorithm to compare initial and operating costs for conventional and hybrid buses consuming diesel fuel and gas with an electric bus having an autonomous ride range of 15, 60 and 250 km is developed. The calculation used correction factors reflecting the rising cost of fuel and electricity with the reducing cost of lithium-ion batteries per kWh. For the calculation of initial expenses the costs of equipment and charging stations are summed up, and for operating expenses the cost of maintenance, fuel and electricity for traction and heating, and payroll of drivers have been taken into account together with the replacement of batteries considering their limited cycle life.

The article describes development of hydrogen energetics over the 2014 to 2018 period. There are statistic data about significant influence of hydrogen vehicles on that energy sector. The development of this means of transport is funded by the governments in different countries and that means big prospects for that technology. Modern researches especially are targeted at optimal approach searching to drive the electrochemical generator (fuel cell) as an initial energy source in the united energy plant. The offered approach is based on the movement characteristics data which were obtained from operated on the real city route trolleybus. The preference is given to use the experimental data for further synthesis of the city fuel cell bus model.

Modern trends of electrical transport sector’s development represent a set of technological innovations from various fields of science. A transition to electric traction drive currently is one of the topical and implemented directions at the global market. There are different of types of transport electrifying and the most common is using batteries which technical and economic characteristics begin to satisfy the world's automakers. Another perspective way is the conversion of natural gas like hydrogen into the electricity for the movement needs. The process of transition to a fully electric traction drive requires an integrated approach and cannot be considered without taking into account power sources limitations, changes in the infrastructure of cities, climatic features, environmental security and economic feasibility. In this context, it makes sense to consider the united power plant consisted of batteries and hydrogen fuel converters because each of them has pros and cons if consider them like a divided power sources. This approach will increase the variability of suitable technological innovations while vehicles for different operating conditions designing.

The power circuit topology of a single-phase automatic compensator of reactive power is synthesized. A control system is developed and the circuit element parameters are determined. The performance of the proposed compensator is confirmed using the simulation model implemented in Simulink. The usage possibilities of the proposed device are shown.

In this paper, the various types of passenger public transport are analyzed. In a study, the diagram of the change in the specific energy consumption of a trolleybus during its annual operation was obtained. The dependence of specific fuel consumption on the ambient temperature has been established based on collected data. In addition, a comparison of initial and operating costs for bus, trolleybus and hybrid with the same capacity was conducted.

The article describes the current status of hydrogen power engineering and electric transport as the main force for a branch development. Modern transport industry turns to the environmentally friendly hydrogen technologies and an optimization of energy resources consumption. The development of new high-tech industries is very important in terms of requirements for environment safety and an emissions level. Gradual development of hydrogen fuel vehicles will reduce a cost of production of one vehicle and make them attractive for using in countries around the world. The rising demand for hydrogen vehicles forces the science to improve the technology of conversion of hydrogen energy into electrical. The development of new control systems for such vehicles, which have high requirements for a fuel quality and the optimization of power plant load, is also stimulated by a demand for hydrogen vehicles.

The increase in passenger flow and the transport speed requires a correspondence of designed vehicles to the high requirements of environmental and transport safety as well as energy efficiency. The compliance of vehicles to high quality standards encourages world manufacturers to develop new types of traction drives with electric traction. In this regard, it seems promising enough to study and develop a hydrogen-fueled power plant, which will make a smooth transition from the use of internal combustion engines to vehicles with the technological principles. The described study is based on experimental data of the on-board recorder installed on trolleys and obtained information about the rolling stock motion pattern. The obtained data allows calculating a power, which must be output by a planned traction drive. To ensure the required running transport qualities, with a low conversion dynamics of hydrogen given, the various energy storage devices in combination with fuel cells are discussed. The power value which could be provided due to a chemical reaction of hydrogen conversion is defined. The further research direction is also mentioned.