Autonomous Electricity Supply Research Articles

ИСПОЛЬЗОВАНИЕ СОЛНЕЧНЫХ БАТАРЕЙ ПРИ ЭНЕРГОСНАБЖЕНИИ СТРЕЛОЧНЫХ ЭЛЕКТРОПРИВОДОВ НА ПРИМЕРЕ ЖЕЛЕЗНЫХ ДОРОГ УЗБЕКИСТАНА

The article is devoted to the research of possibilities to apply solar batteries at power supply of devices of railway automatics and telemechanics in view of geographical position of Uzbekistan. The attention in the research is focused on the questions of energy-effective control of turnout electric drives from solar batteries on intermediate stations. On the example of “Sabir Rakhimov” station, the assessment of average-daily quantity of turnout switches has been made, the calculation of utilized quantity of electric energy for turnout electric drives has been pursued as well as the possibilities of this energy replenishment from solar batteries have been defined. The change in solar battery power in different countries on one and the same type stations has been analyzed. The advantages of alternative energetics for the needs of railway automatics and telemechanics have been described. The calculation of the efficiency of the devices of autonomous electric supply system for last 20 years has been pursued on the basis of statistical data on insolation of Tashkent and Moscow territories (for comparison). The technologies of the location of solar batteries on railway infrastructure objects have been presented. Special attention is paid on perspectives of wide industrial introduction of solar batteries for the energy supply of the devices of railway automatics and remote control.

Ecological and economic efficiency of the use of alternative energy technologies including hydrogen to reduce of the anthropogenic load in the central ecological area of the Baikal natural territory

The central ecological area of the Baikal natural territory covers some districts of the Irkutsk oblast and the Republic of Buryatia, located on the coast of the Lake Baikal. Due to the natural uniqueness and special status of doing economic activity, the assessment of the impact on the environment in this territory is very importance. An analysis of the functioning of energy objects showed that a significant part of the territory is provided with a centralized electricity supply with developed electric grid infrastructure. There are only a few remote settlements with autonomous electricity supply from diesel power plants. The main sources of pollution are numerous boiler houses that provide heat to the population, social and administrative institutions. In all, there are 98 heat energy sources in the territory, of which 66 (or 70%) use coal. The problems of environmental pollution are mainly caused by the use of coal in a small boiler house, worn-out equipment, and the lack of an appropriate level of flue gas treatment. The total estimated emission of pollutants into the atmosphere from heat energy sources is estimated at 20–25 thousand tons per year. In order to reduce the anthropogenic impact from energy objects, it is advisable to use renewable energy sources, hydrogen technologies, coal substitution with environmentally friendly fuels, use of electricity for heat energy supply, installation of environmental protection equipment and the implementation of energy-saving measures. The methodological approach and simulation models developed at MESI SB RAS were used to determine the competitiveness conditions of alternative technologies and energy carriers. The studies evaluated the environmental and economic efficiency of energy production technologies by using specific indicators: the capital intensity of reducing 1 ton of emissions and environmental capital return by 1 million rubles for the conditions of the central ecological area. The potential for reducing emissions into the atmosphere by use of renewable energy sources in autonomous energy supply areas is less than 1% of the current level of total emissions from energy objects. The potential for reducing emissions by replacing boiler houses with a capacity of less than 0,2 Gcal/h by a heat pump units is no more than 12%. The biggest environmental effect can be achieved by using alternative energy carriers including hydrogen instead of coal. Moreover, the potential for reducing emissions is 60% of the total emissions. In addition to these activities are the least capital intensive. The most effectively is the replacement of coal with natural gas. Rational gas consumption in the coastal areas of Lake Baikal is estimated at 175–190 thousand tons of equivalent fuel. The real possibility of transferring small boiler houses to gas arises during the construction of an export gas pipeline from Russia (through the territory of the Irkutsk oblast) to China via Mongolia, or by the small-scale production of liquefied natural gas. The most currently implemented direction is the use of electricity for heat energy supply. The potential volume of electricity to replace coal in boiler houses of the central ecological area is 1,3 TWh per year, however, the competitive electricity tariff is estimated less than 2 US c/kWh, which is several times lower than current tariffs. Hydrogen technology is currently very capital-intensive, but using it in a way similar to using electricity for heat eliminates pollutant and greenhouse gas emissions. Now days, there are no effective financial mechanisms aimed at stimulating the reduction of the anthropogenic pressure on the environment from existing energy sources, including for the use of alternative technologies. As the result, significant financial support is required in the form of special cost compensation mechanisms for energy producers and/or consumers.

Biofuels as an element of energy storage in the electrical supply systems of agro-industrial enterprises

Purpose. Creation of a reliable system of energy supply of agricultural production by accumulating energy in the form of solid biofuels from crop waste. Methods. Methods of system analysis and design of technical systems. Results. The structure of the autonomous system of electrical supply of farm premises on the basis of its own renewable energy sources. Justification of the feasibility of using solid biofuels as an element of energy storage in the conditions of agro-industrial enterprises. Conclusions 1. By 2035, Ukraine should increase the share of renewable energy in its total energy balance to 25%. 2. The most promising natural renewable energy source for Ukraine’s conditions is solar energy (up to 1500 kW٠h/m2). 3. Among renewable energy sources of own production, solid biofuel has significant advantages for the energy supply of agricultural facilities, the cost-output ratio of which is 1:13–17. 4. The use of solid granulated biofuels from crop waste as an accumulation of energy is a defining element of reliable autonomy of energy supply of farm premises. Keywords: autonomous electricity supply, renewable energy, energy storage, solid biofuels, plant waste.

Adapted strategy for large-scale assessment of solar potential on facades in urban areas focusing on the reflection component

The objective of this paper is to propose an adapted method of calculation to evaluate the solar potential on building facades on a large scale. Autonomous electricity supply is nowadays an important issue, particularly during the winter. Thus the facades of buildings, which are better irradiated in winter than the roofs, can provide a response to this issue. Research has been focusing for several years on fine modeling of radiative phenomena in an urban environment. The first challenge is to obtain a physically realistic model considering the phenomena of local reflections. The second challenge is to succeed in implementing this type of simulations on large scales. These two issues are antagonistic: the first implies making the model more complex while the second implies simplifying it. This paper proposes a calculation strategy to reconcile the two issues based on a simplified radiosity method. The results obtained via this strategy were compared to those obtained by measurement and simulation on a theoretical canyon. Subsequently, this calculation strategy has been deployed to real districts in Geneva, Switzerland.

The characteristics of energy security in decentralised zones and autonomous objects of electrification

The article aims to develop a set of objective criteria for assessing the state of energy security in decentralised remote regions of the north, Arctic zones and autonomous energy supply complexes. The authors assessed the potential of renewable energetics, which determines the effectiveness of decentralised energy complexes based on renewable energy sources, in improving the energy security of such entities. The indicators for assessing the energy security of research objects were developed on the basis of an analysis of the ratio of the most significant threats, as well as territorial and situational factors of the autonomous energy of the north and Arctic zones. A study of the security of the research objects allowed the development of a set of criteria for territorial segments and autonomous electrification objects, forming an objective assessment of the energy security of isolated hard-to-reach areas. An analysis of the possibilities of renewable energy sources in achieving certain positions (resource sufficiency, environmental acceptability, technological attainability and reliability) of the energy security of the considered level was conducted. Groups of properties and processes within the territorial framework of a decentralised region, separated by the directions of monitoring the energy security of local energy zones are proposed as objects of indicative analysis. The differentiation of the developed criteria by the levels of the energy zone and decentralised energy complex allowed consideration of all the specific features of these objects and cover the factors of mutual influence with accompanying systems in the formation of the state of energy security. When considering a possible option for the participation of renewable energy sources in the structural and resource provision of autonomous electricity supply, it was found that such diversification will affect both the improvement of some criteria of energy security of the considered level, as well as the deterioration of others.

Design of energy efficient electrotechnical complexes with an autonomous electric supply system

Improving energy efficiency and reducing the costs of creating an autonomous power supply complex for an oil production enterprise is an urgent problem and requires a rational solution. At each stage of the electrical complex development of the oil production enterprise, the purpose is to increase energy efficiency in order to reduce the unit cost of electricity per unit of produced well fluid volume. The electrical complex energy efficiency assessment of the oil production enterprise can be determined by the classical methodology of the energy balance. The task of increasing the energy efficiency of the electrical complex with an autonomous power supply system is to ensure a minimum of fuel costs while maintaining current oil production. Two types of the electrical complex models are proposed: with an individual electricity source and a generation center based on individual diesel generators. A method for calculating the energy parameters of the electrical complex components with installations of different types of pumps is presented. In this case, the energy efficiency is improved due to joint deep and group reactive power compensation and power factor correction by reducing the harmonic components of the current. The electrical complex simulation of a submersible electric motor has been carried out in order to determine the values of voltage and current during switching processes. The autonomous power supply system modeling of an oil production enterprise in case of voltage losses and the simulation of diesel generators with a frequency deviation of the generated voltage during load surges was carried out.

METHOD OF COVERING THE SCHEDULE OF LOADING OF A LIVESTOCK FARM IN THE CASE OF AUTONOMOUS ELECTRICITY SUPPLY, BASED ON BIOGAS PLANTS

The paper proposes a method of tracking the livestock farm load schedule based on the determination of the required generation capacity depending on the actual load schedule. The use of this method allows the management of biogas power plants based on internal combustion engines, depending on changes in the load without power reserve for the time of possible displacement of technological operations. Unlike the power backup method, there is no additional power loss at the time of the reservation, the possible incorrect switches of electrical equipment that do not correspond to the normalized schedule are excluded, there is work in changing the order of operations and the order of switching on the equipment. The use of the method improves the energy efficiency of the biogas plant and also increases the reliability of the livestock farm's autonomous electricity supply system. The calculations of the use of this method for the cattle farm prove its energy efficiency in the conditions of autonomous electricity supply. Developed approaches to tracking the load schedule of the livestock farm allow for the management of biogas power plants depending on changes in the magnitude of the load without power reserve for the time of possible displacement of technological operations. The use of the proposed method is especially relevant for autonomous power systems. The calculations of using this method for a cattle farm testify to its effectiveness, in particular for a small cattle farm with a herd of 60 valid cows, 11 dry and 29 heads of young animals kept in the winter-stall period, the total saving is 82.8 kW ∙ h day.

Methodology for assessing the power of the primary source of the system of autonomous electrical supply with account of the predicted load graphics

When developing new or upgrading existing energy-intensive mobile objects (MO), the main way to ensure the quality parameters of the supply voltage is no worse than in the state grid, overestimation of the primary source (PS) power is 1.5–2 times relative to the maximum power of all electrical energy consumers (EEC) software.The consequence of the existing approach to determine the power of PS are: overestimation of the mass and dimensions of the autonomous power supply system (APSS) by 30–70 %, which significantly reduces speed characteristics, cross-country performance and battery autonomy of MO, as well as worsen the economics of the APSS; the workload of the PS APSS is not more than 35–55 % of the nominal capacity, which leads to a reduction in their service lives.Thus, it is impossible to take into account the peculiarities of the actual current consumption of individual EEC and the impact of their joint operation on specific PS APSS, which leads to additional financial costs and an increase in development time, as well as to the risk of failure during the testing of both the APSS and the equipment connected to it.The proposed approach for estimating the PS power of electric energy in APSS MO allows determining the full power of the EEC in terms of limited information about the EEC taking into account the nature of the load graph, as well as the magnitude and form of current consumption. As a result of analytical calculations according to the above methodology, the PS power can be reduced by 13–45 %, depending on the nature of the load, while maintaining the quality indicators of the supply voltage within acceptable limits.The considered methods for determining the power of the PS APSS will make it possible to determine the limitations for solving the problem of structural-parametric synthesis of the APSS and the algorithm for determining the power of the PS when developing a new or upgrading the existing APSS MO. This will reduce the weight and size parameters of the APSS, thereby increasing the speed characteristics, maneuverability and software permeability of MO, as well as the autonomous operation time and efficiency of the APSS operation.

Method for selecting parameters and assessing efficiency of wind-diesel power plants for autonomous electrical supply systems

The article presents an original technique for selecting parameters and evaluating the efficiency of wind-diesel power plants for isolated power supply systems. The initial data to perform energy calculations are simulation models of electric load and wind speed. The load is simulated using typical schedules of electric loads of a decentralized consumer, taking into account a random component for each hour of the day. To create a simulation model of the wind, a typical climatic series of wind speeds at a prospective site of the power plant has been constructed according to the data of long-term meteorological observations. The proposed technique was verified through the example of choosing a wind-diesel power plant for the village of Ust-Olenyok of the Republic of Sakha (Yakutia).

Diesel-solar electricity supply for remote monasteries

This paper proposes a hybrid autonomous electricity supply system for monasteries as a specific type of load. Chilandar monastery (Mount Athos, Greece) was presented as a case study. Taking into consideration specific location, historical significance, present and future needs of the monastery, and peculiar life style of its inhabitants, a new hybrid system for 400 kWh daily energy consumption and 80 kW peak load have been designed, proposed and elaborated here. It is based on combined use of three new diesel aggregates and a field of photovoltaic panels. Paper further outlines the methodology for selection and sizing up of power generating sources and other equipment. The primary goal for the new system was the reduction of diesel fuel and operational costs. Finally, cost-benefit analysis results of the proposed hybrid system are presented as well.

The current state of affairs and trends in designing effective converters of autonomous electric supply systems

Modern trends in designing converters in the process of modernization of automotive systems for autonomous electric supply of items of special equipment are considered due to the increase in the needs of consumers for supply of electricity. The main attention is paid to the design of voltage converters for DC to DC transformation at higher frequencies.

VARIOMETRIC TESTS FOR ACCELEROMETER SENSORS

Abstract. We present a comprehensive review of several variometric tests recently carried out on a home-made measurement system composed of a tern of low-cost accelerometer sensors of MEMS (Micro-Electro-Mechanical Systems) type equipped with autonomous electric supply and wireless transmission. The most important parameters characterizing the systematic errors, i.e. bias, scale factor and thermal correction factor, have been evaluated by calibration tests based upon the so-called "six -positions" static test proposed by the IEEE 517 Standard. In this way the system optimal configuration has been defined in terms of data acquisition frequency and of scale factor. In addition to such tests, partly documented elsewhere, the results of some sensitivity tests on the influence of external environmental factors are also presented. With the aim of employing the proposed MEMS-based system as a device for monitoring the onset of slope landslides, some further tests have been carried out in order to measure the inclination of rigid objects which the sensors have been fixed to. The most significant results of the tests are illustrated and discussed.