Electric Energy Balance Research Articles

Design of a positive energy district: A Nigerian case study

The potential of possible solutions for the design and implementation of a 50-house Positive Energy District (PED) in Southern Nigeria is presented in this study. Using a transient energy systems simulation software (TRNSYS 18), the energy demand of a typical building is estimated. Different passive design options considering building materials, window sizes, building orientation, roof ventilation are studied to determine the most energy efficient building envelope. TRNSYS and PVSyst (another energy simulation software), are also used to simulate the dynamics of a positive energy building and operation of solar energy systems used for electricity generation, domestic hot water heating and space cooling for Lagos weather conditions. In terms of electric energy balance, the total annual electricity demand is 598,000 kWh while the electricity generated by PV is 728,600 kWh in a year. As regards to site energy balance, annually, the district exports more electricity than it imports. The difference is 110,200 kWh. These results show that in such climatic conditions, despite economic poverty, it is possible to implement the modern PED principles. However, first, it is necessary to reduce energy consumption as much as possible, including solar passive solutions to the building architecture.

Short‐term electric power and energy balance optimization scheduling based on low‐carbon bilateral demand response mechanism from multiple perspectives

AbstractCarbon emissions limit the output of traditional fuel‐fired generating units, significantly affecting the new power system scheduling mechanism. This paper proposes a short‐term electric power and energy balance optimization scheduling method with low‐carbon bilateral demand response (LCBDR). The LCBDR mechanism framework is constructed by combining the analysis of short‐term electric power and energy balance of the system under a dual perspective, along with the electric‐carbon coupling mechanism of the dynamic scheduling on the source‐load side. Based on the carbon emission flow (CEF) theory, the carbon emission index information of load‐side users is obtained. An optimal scheduling model of LCBDR is established. The enhanced decision tree classifier (EDTC) algorithm is used to predict the electricity consumption behavior of transferable load (TL) users, and an improved particle swarm optimization (PSO) algorithm with “ε‐greedy” strategy is proposed to solve this model. Comprehensive case studies from three different perspectives verify that this method can effectively realize the low‐carbon economic operation of the system, with the peak net load reduced by 24.02% and valley net load increased by 20.43%. Compared with a single perspective, the total operational costs can be reduced by 5.27%, and the carbon emissions of users can be reduced by 5.70%.

Development of measures to increase the cruising range of electric buses by installing thermal control system based on phase transitional heat acumulating materials

Introduction. The problems of the mass use of electric buses on urban routes are low operational indicators, including the life of traction batteries (TAB), a significant limited autonomous travel compared to motor vehicles based on internal combustion engines, high cost of batteries, limited implementation of charging infrastructure, deterioration of efficient operation at low ambient temperatures, etc. Most operating parameters depend on the efficiency of replenishment, storage and consumption of electricity on board the electric bus, which include: power reserve, TAB life and economic costs for operation.Materials and methods. The work uses methods of numerical modelling of the movement of the KAMAZ 6282 electric bus under the conditions of the SORT 2: MIXED test cycle.Result. In this work, the balance of electric energy on board the КАМАZ 6282 electric bus during its operation on the city route was analyzed, and the search for the most rational ways of its consumption was carried out due to the introduction of thermal control systems for the passenger compartment and the driver’s workplace based on the installation of a heat accumulator (HA) with phase transfer heat accumulating materials (PFTAM).Discussion and conclusion. The installation of the proposed PFTAM-based system, provided that the range is provided at the level of the serial model, enables to reduce the battery capacity by 24% (up to 549 MJ) or, while maintaining the capacity of 720 MJ, increase the range by 44% up to 130 km.

Probability modelling of storage based‐smart energy hub considering electric vehicles charging stations performance and demand side management

AbstractNowadays, researchers are studying the energy discharging of electric vehicles (EVs) in charging stations. Furthermore, these stations can help maintain the balance of electric energy and reduce costs in the energy hub in the discharging mode. In this regard, this article proposes a probability and possibility approach by the Z‐number method to investigate the uncertainty of the EV owners’ behaviour at charging stations during the discharge of electric energy to the energy hub. Also, here, the uncertainty of electric energy demand, thermal energy, drinking water, and the price of electric energy, thermal energy, drinking water, and electric energy production from a solar power plant has been done by the scenario‐base method. The seawater desalination unit has been modelled to meet the drinking water needs. To check the final results of the proposed method, the mixed integer linear programming (MILP) model has been selected for energy management in the energy hub in the CPLEX optimization solver. The final results show that modelling the behaviour of EV owners in the charging stations using the Z‐number method leads to reduced consumption of some energy carriers in comparison with the fuzzy method in the proposed energy hub.

On functioning of Siberian IDGC branch of PJSC Rosseti – JSC Chitaenergosbyt

Specifics of the functioning of the electric grid company over the period of its activity in 2016 – 2022 are considered. Based on the publicly available data, an analysis of the structural features of the company, as well as the electric energy balance for its transmission to and from the company's networks, taking into account losses arising during the electricity transportation to consumers, was carried out. The characteristics of generating capacity, as well as the number of substations on the Trans-Baikal Territory and in the Republic of Buryatia are presented, their age assessment is given. The level of electricity consumption is analyzed, as well as the structural composition of consumers receiving electric energy through the company's networks. Based on available information about emergency situations, the number of failures that occurred in the company's networks during the period under study, as well as the causes of those failures, were analyzed. It has been established that the greatest number of failures is associated with the wear of electrical grid equipment, which causes a collision of wires of overhead power lines, their breakage, as well as the breakdown of high-voltage insulators. The percentage ratio of the main causes of failures in the company's electrical networks has been determined. Based on the use of Matlab graphic editor technologies, the visualization of the analyzed dependencies was carried out, which enabled to have a demonstration of changes in the number of failures, the amount of under-supplied electrical energy, as well as economic damage from this under-supply. Graphical diagrams are presented and a detailed analysis of the causes of emergency events for the current half of 2022 is given. Reversible malfunctions (unstable failures) are noted, and their share in the total volume of emergency situations is determined. Recommendations have been developed for the company specialists to improve the reliability of power supply. The results obtained can be useful both to the management and specialists of the company in question, as well as to scientific and technical workers and engineering personnel engaged in research in the field of improving the reliability and safety of functioning of electric power systems.

Analysis of the structure of generating capacity and dynamics of electricity consumption in Sredne-Kamchatsky isolated power hub

THE PURPOSE. To examine the features of the location and the overall structure of theSredne-Kamchatskyisolated power hub. To considerthe structure of installed electric capacity and the composition of generating equipment of power plants in the mentioned power hub. To determine the composition and characteristics of the electric grid economy. To analyze and determine the main indicators of electricity consumption and capacity dynamics of the hub. To perform an analysis of the existing balance of power and electric energy, to determine the main technical and economic parameters of the power supply. To consider options for the power supply system development including on the basis of renewable energy sources. METHODS. When solving this problem, we usedmethods of mathematical processing of statistical data and methods of normative forecasting. RESULTS. We considered the special featuresof generating capacities and network infrastructure development,the issues ensuring the long-term and medium-term demand for electric energy and capacity, the formation of stable and favorable conditions for attracting investment in the construction of electric power facilities.The study calculated the current and prospective balances of electricity and capacity in the discussed power hubbased on the analysis of the energy structure of an isolated power unit and the dynamics of electricity consumption. CONCLUSION. Any failure in an isolated system leads to dangerous crisis phenomena and significant economic losses. Thus it is important to provide reliable and efficient power supply to energy isolated territories. The presented comprehensive assessment of the state of the electric power industry in the isolated Sredne-Kamchatsky power plant allows us to predict the prospects for its development within the framework of the overall development of the electric power complex of the Kamchatka Territory.

On the issue of the rate of accidents in Russia's electric networks (by the example of "Rosseti Lenenergo" PJSC)

The article discusses in detail the issues related to the electric energy transmission through the electric PJSC Rosseti Lenenergo networks over the 2014 - 2021 operation period. The purpose of the article is defined as a study of the accident rate in the Company's electrical networks, for which a number of tasks to be considered are formulated. The results of annual reports on the number of failures in the Leningrad region and St. Petersburg electrical networks in 2014 - 2021, broken down by months, are used as source data. To approximate the series of emergency shutdowns, programming algorithms developed by the authors were used, which, through the technologies of the Matlab graphics editor, present the visualization of the studied characteristics. The structure of the electric networks on the Company's books, both in the Leningrad region and in St. Petersburg, is considered. The balance of electric energy for the period under study and the data on its losses during power transmission are analyzed. The assessment of the level of damage to electrical networks by events of stable and unstable failures was made. The principal causes of failures are classified, and their percentages related to the total number of failures across the Company's structural units is established. The relationship is established for the number of failures in particular months of the time period under study. The Company's plans of repair and restoration activities are considered, and the correlation coefficient concept is introduced, which establishes the relationship between the number of emergency shutdowns and the set of measures aimed at ensuring the reliability level for the uninterrupted functioning of electric power transmission facilities.

Multi-criterion Analysis of Selected Power Management Strategies in Smart Home Systems

The introduction of renewable energy sources (RES) and modern building automation solutions, known as smart homes, has greatly increased building energy efficiency. The number of smart home solutions and their elements in closed and open systems continues to grow. This paper attempts to present the energy management abilities in KNX smart home systems based on two different strategies applied to two model houses. Solutions based on a cost-effective strategy and solutions based on a comfort strategy were selected for a multi-criterion analysis based on an electric energy balance in selected buildings, economic analysis and analysis of the selected solutions in terms of user comfort. Finally, a comparative analysis was performed for the results of the multi-criterion analysis of smart home systems combined with RES for two selected buildings.

POSSIBILITY OF BUILDING MICROPROCESSOR RELAY PROTECTION DEVICES ON OPEN ARCHITECTURE

"The article analyzes the structure of relay protection devices of various designs. Based on the Unified Electric Power System of the Republic of Kazakhstan prediction on the electric energy balance the plan to increase the generation of electricity due to the commissioning of new capacities was revealed In addition, the international market of the energy sector and a preliminary forecast for the total demand for energy separeted into the declared scenarios and the scenario of sustainable development of electricity generation, cumulative average annual growth rate, electric capacity by countries, continents and regions were studied. It is determined that the type of power generation system and the fuel used affect the features of building and updating relay protection systems. The hypothesis of the study is the replacement of existing closed solutions on the market of relay protection systems with open hardware and software, which allow developing and applying then various power supply systems, including FPGAs. Within the framework of the study, solutions for building a microprocessor relay on an open architecture were proposed: a block diagram and a developed laboratory stand “relay protection microprocessor on an Arduino board”; «Relay protection microprocessor using FPGA». Comparative data on the characteristics of the boards are presented, where the FPGA board is more effective in all respects. The program was developed in the Quartus Prime 21.1 Lite Edition environment. Based on the results of the work, it can be noted that aim of the further research will be the expansion of the microprocessor relay protection devices based on an open architecture use. Keywords: relay protection, open architecture, FPGA, microprocessor protection, FPGA, automation, control"

Research on the Hydropower Generation Optimal Scheduling of Larger-Scale Cascade Hydropower Stations on Jinsha River and Lancang River

There are some characteristics, such as multi-dimensional, stochastic inflow, non-uniform service and scheduling subjects, in optimal scheduling of power generation. The problem is also subjected to hydrological and meteorological conditions, operation control, water demand, and loads of the power grid. Aiming at the electric power and energy balance problem in the high hydropower system, this paper uses the typical annual load curve to analyse the electricity power and energy balance, so as to better consider the influence of seasonal differences in hydrological conditions on the storage capacity of adjustable hydropower stations and the start-up of thermal power stations, and establish a mid-long term model of hydropower generation optimal scheduling of large-scale cascade hydropower stations. Taking the cascade hydropower stations in the Jinsha River and Lancang River as examples for simulation analysis, and using GUROBI to solve the model, the correctness and effectiveness of the proposed optimal scheduling model are verified.

Impact of wind and solar power plants on the reliability of the IPS

One of the most promising areas in the development of the electric power industry is generally regarded to lie in expanding the share of renewable energy sources (RES) in the electric energy balance of power systems in the form of wind and solar power plants (WPP and SPP), the saving of organic fuel (coal, gas, fuel oil) and the reduction of environmentally harmful emissions into the atmosphere considered to be their most important advantages. However, the impact of RES on the controllability of the modes of operation of electric power systems and on the reliability of the IPS operation remains quite unexplored.Currently, the global energy industry uses 318 million kW of WPP and about 142.4 million kW of SPP, of which the major West European countries account for about 227 million kW, or 49.3%. On average, wind and solar power plants account for almost 30% of the total generating capacity in Western Europe, with Denmark having the largest share of WPP (47%) and Germany having the highest share of SPP (18.6%). However, an uncontrolled growth in the share of WPP and SPP in the structure of generating capacities of power systems begins to manifest itself in a sharp decline in the reliability of the power industry due to the fact that a number of negative properties of WPP and SPP have not been taken into account (at least, to a sufficient extent), which manifested themselves in practice in a system accident in the UK power system that occurred on August 09, 2019, when, as a result of an "ordinary" short circuit, a system accident occurred, with up to 1.1 million consumers with a total load of 1690 MW disconnected from the power supply system for a period of 15 to 45 minutes. This is estimated to have resulted in economic losses for consumers amounting to 12.3–15.0 million USD.The reason for this is that the high sensitivity of WPP, SPP, CCGT and gas piston units to voltage and frequency drops is not properly considered in conditions of insufficient capacity of the rotating (mobile) generation reserve. Damage can be prevented by increasing the rotating reserve within the available reserve of the power system, which will require an increase in funds for maintaining the same due to additional fuel consumption. The ratio of reduction of probable damage to consumers and the cost of additional fuel consumption for maintenance of a required rotating reserve in the power system allows to economically substantiate the strategy and scale of introduction of renewable energy sources to the power industry.

Light Two-Wheeled Electric Vehicle Energy Balance Investigation Using Chassis Dynamometer

Abstract The article presents the methodology for light two-wheeled electric vehicle energy balance investigation using MAHA LPS 3000 chassis dynamometer. For this purpose, the laboratory tests, as well as the road tests, have been performed on the self-constructed light two-wheeled electric vehicle equipped with the 3 kW BLDC motor and the 100.8 V battery pack. The road test data have been used to set up the dynamometer parameters in order to simulate the real road drive taking into account, among others, the rolling resistances and the air drag coefficient. The overall energy consumption for the laboratory tests and the road conditions’ tests have been then compared for different vehicle speeds. In addition, based on the power and the torque characteristics measured on the MAHA chassis dynamometer, the efficiency of the vehicle electric drive system and the efficiency of the battery charging process have been calculated.

Remuneration of Distribution Grids for Enhanced Regenerative Electricity Deployment—An Analysis and Model for the Analysis of Grid Structures in Southern Germany Using Linear Programming

Ecological concerns on the climatic effects of the emissions from electricity production stipulate the remuneration of electricity grids to accept growing amounts of intermittent regenerative electricity feed-in from wind and solar power. Germany’s eager political target to double regenerative electricity production by 2030 puts pressure on grid operators to adapt and restructure their transmission and distribution grids. The ability of local distribution grids to operate autonomous of transmission grid supply is essential to stabilize electricity supply at the level of German federal states. Although congestion management and collaboration at the distribution system operator (DSO) level are promising approaches, relatively few studies address this issue. This study presents a methodology to assess the electric energy balance for the low-voltage grids in the German federal state of Baden-Württemberg, assuming the typical load curves and the interchange potential among local distribution grids by means of linear programming of the supply function and for typical seasonal electricity demands. The model can make a statement about the performance and development requirements for grid architecture for scenarios in 2035 and 2050 when regenerative energies will—according to present legislation—account for more than half of Germany’s electricity supply. The study details the amendment to Baden-Württemberg’s electricity grid required to fit the system to the requirements of regenerative electricity production. The suggested model for grid analysis can be used in further German regions and internationally to systematically remunerate electricity grids for the acceptance of larger amounts of regenerative electricity inflows. This empirical study closes the research gap of assessing the interchange potential among DSO and considers usual power loads and simultaneously usual electricity inflows.

Thermal Optimization of Partitioned Electric Water Heaters for Energy Conservation

Optimum design and selection of storage type electric water heaters were analyzed for energy conservation. The thermal performance of a single tank electric water heater is compared with that of partitioned electric water heater for the same average domestic hourly hot water use pattern according to Becker’s profile. Both water heaters have the same volume capacity and total power rating while the temperature of the hot water was kept between 60 and 65oC. It is concluded that a partitioned electric water heater provides more hot water and reduces energy consumption whereas the upper part of the tank has 25% of the total volume and 75% of the total power rating.
 To evaluate single tank and partitioned electric water heaters transient energy balance equations have been derived and solved. Some assumptions made and thermodynamic properties received to use the evaluate differential equations. To represent water heater models equations required data obtained from literature.

Electric network topology and method of transmission of electric energy

The purpose of the work is to reduce losses and increase energy saving in electric networks. To achieve this goal, a multilevel topology of the electrical network and an asynchronous method for transferring electrical energy between nodes including a load, energy sources, energy storage devices connected in an appropriate manner are proposed. It is shown by the mathematical method that this network topology allows using energy storage devices controlled appropriately and using tele-information technologies to optimize the balance of electric energy in the network, achieving equality of the generated and consumed electricity. Such a network topology and a method of transmitting electrical energy can be the basis of digital technologies in the energy sector (ENERNET).

Experimental investigation of actual situation of using and accounting of recovered energy of regenerative braking mode at the DC traction system

This paper deals with the problems of enhancement of registration and distribution of electric energy which can be obtained from DC electric locomotives by the regenerative braking. According to theoretical researches, it is possible to return approximately 8 - 12% of electric energy which is consumed for electric traction by using of a regenerative braking mode. However in recent years for electric traction networks of JSC “Ukrainian Railways”, this index doesn’t exceed 2.6%. So we consider that the regenerative braking is one of the most prospective ways for energy saving in electric railway transport. Results of the experimental researches which were executed on DC traction substations and VL11M6 electric locomotives are described in this paper. Instantaneous values of voltage and current in different modes have been obtained. The electric energy balance for experimental zone has been performed. Also the ways of distribution and consumption of energy of regenerative braking mode have been analyzed. On this basis of the executed investigations, recommendations about providing of supercapacitor energy storage system for Ukrainian railways are proposed.

ENERGY SAVING AS THE MECHANISM OF MANAGEMENT OF EXPENSES AT THE POWER ENTERPRISES

The analysis of balance of electric energy of Republic of Belarus, import and export of the electric power are carried out in the article. The balance of thermal energy of Republic of Belarus is studied. Results of program execution and plans for prospect are considered. The reserve on economy of fuel and energy resources in the republic is revealed that causes need of the organization of production so that actually to provide the acceptable level of prime cost and a possibility of her continuous decrease taking into account problems of strategic development. Energy saving can serve in power as such mechanism on management of expenses.

The Research of Utilization Hours of Coal-Fired Power Generation Units Based on Electric Energy Balance

With grid-connected scale of clean energy such as wind power and photovoltaic power expanding rapidly and cross-province transmission scale being bigger, utilization hours of coal-fired power generation units become lower and lower in the context of the current slowdown in electricity demand. This paper analyzes the influencing factors from the three aspects of demand, supply and supply and demand balance, and the mathematical model has been constructed based on the electric energy balance. The utilization hours of coal-fired power generation units have been solved considering the relationship among proportion of various types of power installed capacity, the output rate and utilization hours. By carrying out empirical research in Henan Province, the utilization hours of coal-fired units of Henan Province in 2020 has been achieved. The example validates the practicability and the rationality of the model, which can provide a basis for the decision-making for coal-fired power generation enterprises.

Study on Nested-Structured Load Shedding Method of Thermal Power Stations Based on Output Fluctuations

The balance of electric power and energy is important for designing power stations’ load distribution, capacity allocation, and future operation plans, and is thus of vital significance for power design and planning departments. In this paper, we analyzed the correlation between the output fluctuations of power stations and the load fluctuations of the power system in order to study the load change of the power system within a year/month/day, and the output variation amongst the power stations in operation. Reducing the output of hydropower stations or increasing the output of thermal power stations (TPS) could keep the monthly adjustment coefficient of the power system within a certain range, and thus balance the power system’s electric power and energy. The method for calculating the balance of electric power and energy of TPS is also improved. The nested-structured load shedding method (NSLSM), which is based on the calculation principle of the load shedding method, is put forward to iteratively calculate the peak shaving capacity and non-peak shaving capacity of every single thermal power station. In this way, the output process of each thermal power station can be obtained. According to the results and analysis of an example, the proposed methods of calculating monthly adjustment coefficients and the balance of electric power and energy of a thermal power station are validated in terms of correctness, feasibility, and effectiveness.

AN APPROXIMATE CALCULATION OF ENERGY DISSIPATION AND ELECTRIC EROSION OF ELECTRODES IN THE HIGH-VOLTAGE HIGH-CURRENT AIR SWITCH OF ATMOSPHERIC PRESSURE

Purpose. To obtain new calculation correlations, determining approximate energy dissipation and electric erosion of massive basic metallic electrodes in the high-voltage high-current air switchboard (HVCAS) of atmospheric pressure, in-use in the bit chain of the high-voltage electrophysics setting (HVES) with the powerful capacity store of energy (CSE). Methodology. Electrophysics bases of technique of high-voltage and large impulsive currents (LIC), scientific and technical bases of development and planning of high-voltage heavy-current impulsive electro-devices, including HVES and powerful CSE, and also methods of measuring in their bit chains of LIC of the microsecond temporal range. Results. On the basis of new engineering approach the results of calculation estimation of excretions energy and electric erosion of massive basic metallic electrodes are resulted in probed HVCAS. New correlations are obtained for the approximate calculation of thermal energy, selected in an impulsive air spark and on the workings surfaces of anode and cathode of HVCAS. It is entered and a new electrophysics concept, touching equivalent active resistance of impulsive air spark, is mathematically certain. New formulas are obtained for the approximate calculation of most depth of single round crater of destruction on the workings surfaces of basic metallic electrodes of HVCAS, and also mass of metal, thrown out magnetic pressure from this crater of destruction on the electrodes of switch for one electric discharge through them powerful CSE HVES. It is shown that the radius of the indicated single crater of destruction is approximately equal to the maximal radius of plasma channel of a spark discharge between a cathode and anode of HVCAS. The executed high-current experiments in the bit chain of HVES with powerful CSE validated row of the got and in-use calculation correlations for the estimation of energy dissipation and electric erosion of metallic electrodes in examined HVCAS. Originality. New engineering approach is developed for the approximate calculation and estimation of energy dissipation and electric erosion of basic metallic electrodes in HVCAS. A formula is firstly got for approximate calculation unchanging in the process of swaying or aperiodic discharge of CSE HVES on the electric loading of active resistance of impulsive air spark between the electrodes of probed HVCAS. Practical value. Drawing on the got results in a high-voltage impulsive technique provides operative implementation of calculation of balance of electric energy in the high-current circuit of HVES with powerful CSE and point electric load, and also prognostication of the technical state of workings surfaces of massive basic metallic electrodes of HVCAS.