Local Electrical Network Research Articles

Increase the efficiency of implementation and interaction of distributed generation with the local electric network

Increase the efficiency of implementation and interaction of distributed generation with the local electric network

A geographically disaggregated approach to integrate low-carbon technologies across local electricity networks

Meeting climate targets requires widespread deployment of low-carbon technologies such as distributed photovoltaics, heat pumps and electric vehicles. Without mitigating actions, changing power flows associated with these technologies would adversely impact some local networks. The extent of these impacts, and the optimal means of avoiding them, remains unclear. Here we use local-level data and network simulation to estimate variation in future network upgrade costs in over 40,000 geographical regions comprising all of Great Britain. We find that costs vary substantially between localities, and are typically highest in urban areas, and areas with highest deployment of heat pumps and electric vehicles. We estimate reductions in required upgrades associated with local flexibility, which vary substantially between localities. We show that using geographically disaggregated data to inform flexibility deployment across the country could reduce network upgrade costs by hundreds of millions of pounds relative to an approach that treats localities as homogeneous.

DECENTRALIZATION – THE MAIN WAY FOR THE TRANSFORMATION OF THE ENERGY INDUSTRY OF UKRAINE

Topicality. The events of November 2022 showed the absolute instability of Ukraine's centralized energy system. Up to 40% of the centralized energy infrastructure was disabled in two days. Millions of people were left without electricity, heat and water for a long time. Therefore, it is very important to develop the energy sector of the state in the future, taking into account the needs of Ukraine's decentralization policy, in particular, local communitiesAim and tasks. The purpose of the research is to determine the imperatives of decentralization of the energy sector of Ukraine. The main way of developing the energy system of the state is the transition from a centralized to a distributed system. The location of generation systems in united communities makes it possible to switch to systems of cogeneration of electric and thermal energy to increase the efficiency of installed capacities and save fuel significantly by up to 40%.Materials and Methods. The methodological basis for the formation of regional policy should become the best of the world and European practices of the country`s energy sector development. Active use of the methods of system analysis, expert assessment on the implementation of decentralization systems of the energy industry is a guarantee of achieving the priorities of national security of Ukraine in the post-war period. Priority support from the EU and others international donors refers to those projects and programs aimed at decentralization, decarbonization, local economic sustainability and energy independence.Research results. The research substantiates that local communities have great opportunities for using alternative renewable resources for the generation of electricity and thermal energy. First of all, it is biomass, biogas, solar energy, wind energy and geothermal energy. In particular, the authors proved that due to the installation of means of electric energy accumulation, it is possible to raise the level of use of the installed capacities of solar and wind power plants by another 50% and to bring the total level of use of the installed energy capacities to 70%.Conclusions. The active implementation of alternative energy sources into economic practice can become the basis of the national security of the state in the post-war period. It is suggested that Communities use nearby agricultural waste and solid household waste as fuel instead of imported fossil fuel. It is also proposed to create local electric networks combined into virtual power plants within the framework of united communities, including not only all types of generation available on the territory, but also systems of short-term and long-term storage of electric energy. For the long-term storage of large amounts of electrical energy, it is suggested to use accumulators based on cryogenic liquids. It has been proven that due to the installation of means of electric energy accumulation, it is possible to raise the level of use of the installed capacities of solar and wind power plants by another 50% and to bring the total level of use of the installed energy capacities to 70%. Virtual power plants make it possible to significantly increase the amount of generated (consumed) electricity without additional investment costs. Such technologies meet the requirements of the European Union for candidate countries to join the Union and open the possibility of financing projects related to the restoration of the energy system of Ukraine based on renewable sources and advanced energy-efficient technologies.

Application of Heat Pumps in New Housing Estates in Cities Suburbs as an Means of Energy Transformation in Poland

This paper presents possible applications of heat pumps in buildings during the energy transformation and decarbonization of a country whose energy sector is highly centralized and based on coal. Contemporary cities are spreading beyond the existing borders and new areas cannot be supplied by the existing centralized district heating system. The only form of energy that is available on the outskirts of cities is electricity, which means that it must be used for all energy needs, including heating. In such a case, the use of heat pumps is perfectly justified in terms of energy, economy and environment, especially when they are coupled with photovoltaic systems. Hypothetical micro housing estate energy systems based on photovoltaics and heat pumps are analyzed in the paper. New options for configuration and operation of the energy systems are considered. Results of a simulation study show that by creating a common local electricity network and a local heating network powered by a central heat pump, the direct use of electricity generated in the local photovoltaic systems increases from 25% to at least 35%, thanks to enabling more even storing and consuming of solar energy during a day, compared to the independent operation of energy systems at individual houses.

MATHEMATICAL MODEL OF A FLEXIBLE MICRO GRID INTEGRATED INTO THE COUNTRY GRID

The functioning of local electric networks ('Micro Grid') is described, which due to the development of Smart Network technologies, distributed generation and electricity storage systems received an incentive for development. The structural decomposition of the market model is suggested for the 'Top-Level Market' and 'Micro Grid' local systems to reflect the interaction of the 'Micro Grid' with the wholesale electricity market. Load regulation instruments are described, which ensure the flexibility of the Micro Grid. A mathematical model of the 'Micro Grid' system is proposed, which formulated as a Unit commitment problem. The computational experiment shows the adequacy of the results of modelling of 'Micro Grid' systems. References 9, figures 4, tables 2.

Smart grid systems infrastructures and distributed solar power generation in urban slums–A case study and energy policy in <i>Rio de Janeiro</i>

<abstract> <p>This article discusses the relationship between urban slums and the management of the urban infrastructure network (electrification). An extensive survey of the scientific literature on the subject points out the main challenges and possible solutions for fixing precarious electrical infrastructure in urban slums through the promotion of public policies and the establishment of new arrangements based on distributed generation technologies and smart grid. A dialogue was also developed involving topics such as sustainable development and electrification of slums; relationship between communities and modernization of electrification; and emerging and sustainable technologies in the context of urban slums. Thus, a design was constructed that triggered a discussion of the relationship between this work and several other works found in the literature. This research indicates the need to strengthen local governance and the participation of urban slums for the technological modernization of the local electrical network, mainly with the implementation of smart grid and photovoltaic generation systems.</p> </abstract>

Use and improvement of automatic systems for control of reduced electric power sources in local electric networks

THE PURPOSE. Consider the use of automatic systems for controlling reduced sources of electricity in local electrical networks. Explore the possibilities of expanding the functions of such automatic control systems to improve the quality of electricity in terms of eliminating power exchange and common-mode oscillations. METHODS. Studies of diesel generator units operating in parallel in local electrical networks were carried out using mathematical modeling methods. The mathematical model takes into account the presence of the "backlash" phenomenon in the speed control loops. RESULTS. The expediency of using batteries, rectifier and inverter converters in local electrical networks is noted. Experimental studies in the local electrical network revealed the existence of power exchange and common-mode oscillations. Mathematical modeling also confirmed the occurrence of power exchange oscillations in the local electrical network due to the “backlash” in the frequency controller circuit, as well as power common-mode oscillations due to the difference in the frequency controller transmission coefficients for diesel generator units operating in parallel. A map of the dependence of the amplitude of power exchange oscillations on backlash gaps and a map of the dependence of the amplitude of power common-mode oscillations on the values of the gain of the frequency controller are obtained. CONCLUSION. The possibility of eliminating power exchange and common-mode oscillations by reducing and ensuring equality of the transmission coefficients of frequency controllers has been established. Adding the function of eliminating power exchange and common-mode oscillations to automatic control systems for reduced sources of electricity in local electrical networks ensures that the required quality of electricity is maintained in quasi-steady operating modes.

Electrical power supply system planning for a modern catenary-free rapid charging

Electric power supply system planning is practically an important function of the modern light rail transit system with catenary free operation and rapid charging. Installing a modern dynamic load of the traction power supply system with the local electric distribution network needs to consider its capacity and feeder to support enough and efficiently. In this paper, the design of the electrical power supply system of the pilot project of Nakhon Ratchasima Green Line light rail system with 11.6-km line length and 21 passenger stations operated with catenary-free and powered with an on-board energy storage device has been proposed and planned to replace the old local transportation. The traction power supply of the light rail system drawn power from the MV distribution feeder practically consist of receiving power substation, MV power feeding system power feeder substation, charging power supply and service power supply have been designed provided the configuration circuit. A rapid charge system to delivery high power to fulfill the on-board energy storage is considered to recharge at passenger stations with an overhead conductor or wireless power transfer during a short dwell time. A number of charging station is determined accordingly the capacity of the power substation and its positions. The traction power drawn by a train service round-trip that related to the capacity of the power substation as a charging station has been calculated by the simulation of the train movement. The regenerative braking energy during train operated in braking mode is also considered as a partial charging energy the on-board energy storage device. From the proposed design, the motive energy consumption of each scenario charging formations obtains the maximum charging energy drawn by the train between charging points, the capacity of on-board energy storage devices, maximum charging power and the total charging points.

Community-Based Microgrids: Literature Review and Pathways to Decarbonise the Local Electricity Network

This article addresses the suitable approaches for empowering energy citizens and smart energy communities through the development of community-based microgrid (C-MG) solutions while taking into consideration the functional architectural layers and system integration topologies, interoperability issues, strategies for consumer-centric energy trading under the local electricity market (LEM) mechanism, and socio-economic aspects. Thus, this article presents state-of-the-art microgrid solutions for the smart energy community along with their motivation, advantages and challenges, comprehensibly contrasted between the recommended generic architecture and every other reported structure. The notion of LEM for peer-to-peer (P2P) energy exchange inside a transactive energy system based on a flexible consumer-centric and bottom-up perspective towards the participation in the wholesale electricity market (WEM) is also reviewed and critically explored. Furthermore, the article reviews the interoperability issues in relation to the development of C-MG including energy trading facilities. The article’s overall contribution is that it paves the path for advanced research and industrialisation in the field of smart energy communities through the analytical recommendations of the C-MG architecture and DER (distributed energy resource) integration structure, considering the future trend of local energy markets and socio-economic aspects.

Towards low-carbon district heating: Investigating the socio-technical challenges of the urban energy transition

District heating is a major energy infrastructure in many urban settlements in the world, contributing significantly to greenhouse gas emissions. Decarbonising district heating is an important step towards the realisation of a carbon-neutral society that entails considerable socio-technical change. Building on sustainability transitions literature that has dealt with socio-technical reconfiguration, this paper investigates the barriers to the implementation of a low-carbon district heating system that is based on biomass incineration minimisation and the total phasing out of fossil fuels. Empirically, the study relies on an extensive stakeholder analysis that involved 44 organisations representing technology providers, energy companies, industry organisations, policymakers, local authorities and researchers. The results show that while several stakeholder groups could converge on key issues such as the need to support certain technological niches and the danger of a biomass lock-in, divergences regarding barriers to be removed existed between policymakers, new entrant firms, and building owners. Cities were considered important actors for the implementation of the proposed low-carbon district heating concept. However, they should encourage building owners' participation in demand response schemes, decentralized renewable energy production, and the re-design of local electricity networks to support district heating electrification.

Rooftop PV: Potential and Impacts in a Complex Territory

When developing a sustainability plan in a complex and heavily urbanized territory, one of the most relevant options available is installing rooftop photovoltaic (PV) panels. Thus, it is essential to determine the amount of available surface and the potential impact of such installations on the energy and emission budget of the area. Instead of processing remotely sensed imagery, which is a long process and does not allow considering the buildings’ ownership, this study develops an approach based on a cluster analysis of the urban/morphological characteristics of the municipalities. Once a clear group diversification is obtained, the roof surface of the center of gravity of each cluster is extrapolated to all similar settlements. This, together with the information of local solar irradiation, allowed us to compute each cluster’s potential solar energy production and its capability to respond to the local energy demand, a key parameter to decide about the possibility of a local smart electricity network. Finally, the emissions avoided thanks to solar PV development are computed in terms of carbon dioxide and other relevant pollutants. This approach is applied to the residential rooftop of Lombardy, a Northern Italy region with a wide variety of urban morphologies and landscapes. The potential production of rooftop PV exceeds the estimated electricity consumption of residential buildings and would allow sparing almost 4 M ton of CO2 equivalent or 5% of the overall regional emissions.

Price Efficiency, Green Transition and Channels for Regulating Natural Monopolies: The Case of Power Distribution System Operators (DSOs)

The subject of this chapter is the governance system of the distribution system operators (DSOs), i.e. the companies that own, operate and develop regional and local electricity networks. These companies are natural monopolies, and subsequently need strong regulation by public authorities and/or by consumers. The role of the DSOs has been changing fundamentally in recent years, together with the rest of the electricity system, due to the transition from stored fossil fuel-based electricity to electricity based on fluctuating renewable energy sources. The paper analyses the changing circumstances for the DSOs in the development of integrated smart energy systems, based on an innovative theoretical framework with a strong focus on ownership in the understanding of governance of natural monopolies. After a comparative analysis of shareholder versus consumer ownership, based on two cases, the paper sets up several conclusive recommendations about ownership, governance and the new role of the DSOs in the developing smart energy system.

Superior microwave absorbing properties of O, S, N codoped carbon planar helixes via carbonization of polypyrrole spiral nanowires

Lightweight, and broad and strong absorption are still a huge challenge for electromagnetic (EM) wave absorbers. Here, we propose a facile oxidative polymerization-carbonization strategy to synthesize O, S, N codoped carbon planar helixes for superior EM wave absorbers. The spiral cetyltrimethylammounium bromide crystallites act as a template for the in-situ oxidative polymerization of pyrroles into ordered PPy spiral nanowires. Sintering temperature (Ts) was used to adjust the defects, heteroatoms, graphitization degree, and properties of the carbonized products. With Ts varying from 400 °C to 800 °C, internal stress and heteroatom (N, O, S) content decreased, causing the decreased defect/dipole polarization and increased graphitization degree and conductivity loss. As a result, one broad high-frequency absorption band was exhibited by carbon planar helixes produced at 400 °C− 500 °C, two broad absorption bands were exhibited by those formed at 600 °C, and three absorption bands were exhibited by those formed at 700 °C − 800 °C. The carbon planar helix formed at 700 °C exhibited broader bandwidth (4.96 GHz), thinner sample thickness (1.4 mm), and stronger absorption (−35.44 dB) than those of other absorbers. The superior properties are attributed to a combination of dipole/defect polarization, interface polarization, conductivity loss, multiple scattering, and multiple LC-resonances generated from the unique planar helical structure, defects, heteroatoms, and local electric network.

Matlab-model of a solar photovoltaic station integrated with a local electrical network

This article considers a model of a solar photovoltaic station (PVS) integrated with a local electrical network on the example of a 20 kW PVS installed in the building of the Tashkent State Technical University named after Islom Karimov. The Basic SIMULINK model of an equivalent PVS was used for analysis and comparison of PVS parameters. It is shown that the parameters for the mathematical model match the experimental parameters obtained under natural operating conditions at remarkable points. This model of PVS will serve as an experimental and laboratory stand in the teaching of students of the University for the subject “Renewable energy sources” (RES).

Beyond energy savings: The necessity of optimising smart electricity systems with resource efficiency and coherent waste policy in Europe

European Union (EU) law currently poses energy efficiency requirements which could be achieved in part by using demand side response (DSR). This includes the use of storage and smart appliances. However, such means are not stimulated in the electricity market(s) as there is insufficient demand for flexibility from these appliances. This originates from the current lack of value for flexibility, and, consequently, of incentives for investing in electric and electronic equipment (EEE) able to provide it. One solution could be to include ‘smartness’ in the design and labelling of appliances. This article introduces the idea of expanding already existing legal instruments - the energy labelling and ecodesign frameworks – to include the ‘flexibility potential’ of household EEE. This would link regulation for such equipment to the requirements of a more efficient electricity system and allow for standards and methods to assess potential system efficiency gains to be created, and ideally, a market for the production and sale of equipment providing DSR. Ultimately, it would contribute to increased efficiency of EEE and especially of the electricity system. Considering that energy and resource efficiency are priorities in EU law and policy, the article proposes a ‘full-chain approach’ that expands the concept of lifecycle of household EEE to include their potential to interact with the local electricity network by means of DSR. The article studies EU policy instruments addressing energy and resource efficiency, and EU legislation on the electricity system with a focus on household EEE and their potential to increase energy efficiency by DSR.

Frustration, confusion and excitement: Mixed emotional responses to new household solar-battery systems in Australia

In Australia, despite widespread adoption of solar photovoltaic (PV) power, and the growing familiarity with other energy technologies, technologies associated with renewable generation in the home may still present perceived risks to householders and be the subject of contestation. In this paper, we argue that a focus on emotions can complement existing approaches for understanding the messiness and complexity of trade-offs households negotiate as they experience the process of purchasing, installing and using smart energy technologies. We explore emotional responses to a system of automated ‘smart’ renewable storage designed to support the local electricity network trialed with thirty-four households on Bruny Island, in Tasmania, Australia. We integrate our focus on emotions with a relational-materialist theory of affordances which helps us to unpack the specific features of the technology – which may encourage, discourage, demand, refuse and allow certain household practices as well as trading energy from their battery for financial benefit. The institutional design of the technology delivery which involved minimal decision making power from householders had a significantly negative impact on the lived experiences of householders with the technology. Our focus on affect also revealed the stress and frustration experienced by householders who could not understand and control the technology in the way desired and in line with islander attitudes of self-reliance and autonomy. We can also learn from the positive emotions of enthusiasm, delight and satisfaction experienced by householders. We find affordances theory is a helpful approach for unpacking specific features of the system that provoke different, sometimes even contradictory, responses, yet also suggest refinements to the theory to incorporate the context in which the technology comes to be in people’s lives.

Operation of power distribution networks with new and flexible loads: A case of existing residential low voltage network

This paper aims to visualize how the planned electrification of heat demand together with the utilization of energy flexibility in buildings will influence the performance of local electricity network. Thereby, the work contributes to the research on smart energy system in the residential sector. The flexibility service is provided by two demand-side-management strategies a) activation of the thermal mass to modulate load profile of a heat pump, b) control of household appliances’ starting times. Three configurations of load mix in the local electricity network are investigated: a) domination of non-renovated houses, b) with equal share of high and low heat demand houses, c) domination of energy efficient houses. The model is soft-coupled and anchored in existing low voltage (LV) network and existing residential buildings. The energy flexible buildings enhance the LV network performance, by decreasing the afternoon peaks, without compromising the occupants’ thermal comfort. The highest impact is for the LV network dominated by energy efficient houses. There are also new challenges, namely the newly created peak loads and transformer overloading during night time. It is a consequence of uniform price signal sent to all flexible customers and electrification of heating demand without parallel improvement of energy performance.

Experimental, Numerical and Application Analysis of Hydrokinetic Turbine Performance with Fixed Rotating Blades

In this study, a hydrokinetic turbine is designed for the high-altitude regions where local electricity network lines are difficult to reach. If there was a stream flow around, electricity production could be possible and necessary because of environmental reasons. The performance of the hydrokinetic turbine was investigated experimentally and numerically. The numerical analyses of the turbine system were performed via MATLAB/Simulink version R2014a. Except power-based performance characteristics, efficiency of the system in terms of installation and necessary investment costs were also investigated. It is calculated that the system to be established on a river with a water flow rate of 30 m3/h will meet the investment cost in approximately 8 years.

Meteorological input data effect on sizing stand-alone photovoltaic systems

The exploitation of Renewable Energy Sources (RES) has already been proved as a promising power source for a sustainable future in energy supply, to cover the world’s energy demand. Solar energy is considered the most abundant RES of all, while being available in every part of our planet makes it favorable for distributed RES energy production systems. Solar-based stand-alone power systems, installed in remote areas far from the main local electricity networks, can be cost efficient and even provide energy security given that they have been carefully sized. Moreover, stand-alone photovoltaic systems can highly contribute to distributed renewable energy and microgrid networks even without other RES combination if they integrate with an appropriate energy storage (ES) system. During the sizing procedure of a photovoltaic (PV) plant, the solar potential of the area is the dominant parameter. The use of solar energy values, which may deviate from the actual values, has a relatively small impact on the overall energy assessment of interconnected photovoltaic installations. However, in the case of stand-alone PV systems, where the user requires energy autonomy, it is necessary to use hourly solar radiation along with air temperature values with increased reliability in order to determine the most cost effective combination of PV-ES system. Although there is an extended literature on stand-alone PV systems sizing procedures, the effect of using different input meteorological data on system’s size has not been sufficiently addressed. In this context, the present study examines the use of different meteorological input data of solar radiation and air temperature with data series from 12 individual years, a Mean Year (MY) and a Typical Meteorological Year (TMY). Although the TMY has been mainly used in building’s energy calculations, the results of the present work prove that the use of a TMY increases the power system reliability if compared with sizing the system by using time series of individual years or a MY. The case study presented in the specific work concerns an application of combined PV-ES able to provide energy autonomy to a domestic consumer, in a remote area in the island of Rhodes.

A GIS-Based Method for Identification of Wide Area Rooftop Suitability for Minimum Size PV Systems Using LiDAR Data and Photogrammetry

Knowledge of roof geometry and physical features is essential for evaluation of the impact of multiple rooftop solar photovoltaic (PV) system installations on local electricity networks. The paper starts by listing current methods used and stating their strengths and weaknesses. No current method is capable of delivering accurate results with publicly available input data. Hence a different approach is developed, based on slope and aspect using aircraft-based Light Detection and Ranging (LiDAR) data, building footprint data, GIS (Geographical Information Systems) tools, and aerial photographs. It assesses each roof’s suitability for PV deployment. That is, the characteristics of each roof are examined for fitting of at least a minimum size solar power system. In this way the minimum potential solar yield for region or city may be obtained. Accuracy is determined by ground-truthing against a database of 886 household systems. This is the largest validation of a rooftop assessment method to date. The method is flexible with few prior assumptions. It can generate data for various PV scenarios and future analyses.