Electrical Energy Distribution Networks Research Articles

Decentralized Active Demand Response (DADR) system for improvement of frequency stability in distribution network

The concepts of decentralized demand response systems are present in the state of the art literature, however, the material is limited to general ideas and possible system services. In this paper the original and application ready proposition of Decentralized Active Demand Response (DADR) system realization is presented in the form of a stochastic control algorithm. Such an approach to the system description enables simulation investigations of the DADR system as an element of dynamic stability improvement of an electrical energy distribution network. The results obtained from simulations have confirmed that the proposed DADR solution, because of its high dynamic response in dealing with disturbance phenomena, might be used as part of both primary and secondary Load Frequency Control in electrical power systems.

“Internet of Things” Contribution to Electrical Energy Efficiency and Society Eco-Education

Abstract This paper aims at analyzing the place and possible contribution of “Internet of Things” (IoT) in the context of the EU’s ambitious climate and energy targets for 2020. Using qualitative methodology we are mainly focusing on Demand Side Management (DSM) as an effective method in balancing the load of Electrical Distribution Networks. The role of IoT in DSM is to enable and enhance electrical energy peak demand reduction and its maximum uniform time-distribution achieved through society’s eco-education. Using computational tools such as Data Mining and Recommender System we can achieve results at the level of electrical energy distribution network reflected in peak reduction and its uniform time distribution.

Implementation of Machine-to-Machine Solutions to Improve Quality of Service for Electrical Energy Distribution Networks in Colombia

In order to incorporate smart elements into distribution networks at ITELCA laboratories in Bogota-Colombia, a Machine-to-Machine-based solution has been developed. This solution aids in the process of low-cost electrical fault location, which contributes to improving quality of service, particularly by shortening interruption time spans in mid-voltage grids. The implementation makes use of a GENEKO modem that exploits its digital inputs together with a full coverage of certain required auxiliary services so as to generate proper detection signals whenever failure currents occur; which allows incorporating the latest failure detection technology into the system.

Diagnosis of defects on medium voltage electric energy distribution networks: The case of rural zone’s supply

An analysis carried out on the High Voltage A (HVA) electricity power distribution network run by Cameroon’s AES-SONEL company shows that losses are very high due to energy which is produced but not distributed and that the duration of power interruptions as a result of the defects is long due to the time used in searching for these defects, particularly in rural zone’s supply. Given that quick detection of defects is a sure means of improving availability and productivity in any company, we hereby propose a system of real-time diagnosis of the defects on a rural network’s supply of AES-SONEL’s electric power distribution network, the case of. After an inventory of typical defects on electric power networks and the proposal of a tool for their identification, we propose a system for the detection and localization of these various failures. The implementation of the system on a Programmable Logic Controller (PLC) enables the performance of the system to be assessed.

Performance of single wire earth return transformers with amorphous alloy core in a rural electric energy distribution system

In this paper are presented some considerations about the performance of single wire earth return amorphous alloy core transformers in comparison with conventional silicon steel sheets cores transformers used in rural electric energy distribution network. It has been recognized that amorphous metal core transformers improve electrical power distribution efficiency by reducing transformer core losses. This reduction is due to some electromagnetic properties of the amorphous alloys such as: high magnetic permeability, high resistivity, and low coercivity. Experimental results obtained with some single-phase, 60 Hz, 5 kVA amorphous core transformers installed in a rural area electric distribution system in Northern Brazil have been confirming their superior performance in comparison to identical nominal rated transformers built with conventional silicon steel cores, particularly with regard to the excitation power and to the no-load losses.

Influence of the photovoltaic generation in a small distribution network

In this paper are presented the results of a study carried out with the data of a electrical energy distribution network in a village in the region of La Rioja (Spain). In this distribution network, property of a small utility, is connected a photovoltaic power plant with a ca pacity comparable with the total load connected to the network in some hours. In the study there have been used actual load and generation data, discussing the influence of the photovoltaic generation on the net demand of the village over a period of two years (2009-2010). This study is a first phase for the applicatio n of demand side management actions for adjusting the load curves with generation curves. In a second phase the influence of new distributed generation facilities, based on renewabl e sources (wind, biomass, cogeneration, etc.) will be cons idered in order to minimize the dependence of the village from external supplies.

Diagnosis of defects on Medium Voltage Electric Energy Distribution Networks

An analysis of the Medium Voltage (MV) electricity power distribution network in the operated by Cameroon’s AES-SONEL company shows that losses are very high due to energy which is produced but not distributed and that the duration of power interruptions as a result of these defects is long due to the time used in searching for the defects. Given that quick detection of defects is a sure means of improving availability and productivity in any company, we hereby propose a system of real-time diagnosis of the defects on AES-SONEL’s electric power distribution network. After an inventory of typical defects on electric power networks and the proposal of a tool for their identification, we propose a system for the detection and localization of these various failures. The implementation of the system on a Programmable Logic Controller (PLC) enables the performance of the system to be assessed.

Estudando campos elétricos de linhas trifásicas pelo método da cuba eletrolítica

Neste artigo, discutimos a implementação de um experimento simples destinado a laboratórios didáticos de eletromagnetismo como material de apoio para a investigação de campos elétricos provenientes de linhas trifásicas, empregando o clássico método da cuba eletrolítica. O experimento mostra que é possível obter informações sobre regiões de segurança para exposição de trabalhadores e estudos sobre o possível impacto ambiental de torres de redes de distribuição de energia elétrica intermunicipais.

Optimization of the Topology of Electric Energy Distribution Networks by Using Algorithm Inspired on Ant Behavior

An algorithm inspired on ant behavior is developed in order to find out the topology of an electric energy distribution network with minimum power loss. The algorithm performance is investigated in hypothetical and actual circuits. When applied in an actual distribution system of a region of the State of Sao Paulo (Brazil), the solution found by the algorithm presents loss lower than the topology built by the concessionary company.

Volume and surface measurements of flaws in polymeric insulators using X-ray computed tomography

This paper presents results of a technique developed to measure the volume and the surface area of flaws in pin-type polymer insulators used in electrical energy distribution networks by means of computed tomography (CT). The tomography images were reconstructed using 180 digital radiographs (projections) acquired from a high-resolution system (a 50 μm x 50 μm, a-Si pixel detector). An acrylic phantom containing 12 cylindrical holes of known volume was used to test the tomography measurement system. In order to improve the quality of tomography images, two procedures were used, namely, 'subtraction of dark image' and 'correction oflight field', as well as a sequence of filters such as the median and the Gaussian. Image processing techniques were used for the segmentation of flaws in the CT images. The Marching Cubes algorithm was used in the visualisation process and the Decimation algorithm was used to obtain volume and surface area measurements of flaws. The programs were developed in C++ and Java, using the VTK - Visualisation Toolkit library. The results obtained showed to be satisfactory for quantitatively and qualitatively analysing the effects of electrical discharges in insulation materials such as insulators and cables.

Optimal control of investments for quality of supply improvement in electrical energy distribution networks

This paper considers the problem of deciding multi-period investments for maintenance and upgrade of electrical energy distribution networks. After describing the network as a constrained hybrid dynamical system, optimal control theory is applied to optimize profit under a complex incentive/penalty mechanism imposed by public authorities. The dynamics of the system and the cost function are translated into a mixed integer optimization model, whose solution gives the optimal investment policy over the multi-period horizon. While for a reduced-size test problem the pure mixed-integer approach provides the best optimal control policy, for real-life large-scale scenarios a heuristic solution is also introduced. Finally, the uncertainty associated with the dynamical model of the network is taken care of by adopting ideas from stochastic programming.

Um estudo comparativo entre a teoria dos jogos cooperativos e uma heurística aplicados a um problema real de alocação de custos

Neste artigo fizemos o estudo de técnicas para a resolução de problemas de alocação de custos em redes de acesso com um grande número de usuários, como acontece em redes de informação, de distribuição de energia elétrica, de esgoto entre outras. O problema é como distribuir os custos envolvidos entre os usuários da rede. Para responder esta questão, fizemos uma caracterização do estado da arte para a teoria dos jogos cooperativos. Encontramos aplicação em um problema real de alocação de custos e usando a teoria revisada, definimos o problema, um modelo matemático associado a ele, e selecionamos alguns conceitos de solução. Além disso, também propusemos uma heurística que foi aplicada e comparada com as soluções obtidas pela teoria.

Interruption modelling in medium voltage electrical networks

Failures frequently occur in developing countries' electrical energy distribution networks. This paper proposes an approach to network reliability through modelling the interruptions on medium voltage lines. This modelling is based on a representative feeder sampling of a source station in an urban area. In order to determine the probability law governing these interruptions, statistical techniques were used: density estimation using the kernel method and approximation by the least squares. The results we obtained show that, from the quality of the equipment and their maintenance, interruptions for a given network follow a truncated and shifted gamma distribution or a truncated normal law. For the managers of such systems, these results would allow, amongst other things, reduction in the probability of failure, thus improving operational safety on electricity distribution with medium voltage lines.