A. R. Abaide

AHP Decision-Making Algorithm to Allocate Remotely Controlled Switches in Distribution Networks

Continuity in power supply for the consumers is a permanent concern from the utilities, pursued with the development of technological solutions in order to improve the performance of network restoration conditions. Using remotely controlled switches corresponds to one possible approach to reach such an improvement and gives some convenient remote resources, such as the fault detect, isolation, and transfer loads. This paper presents a methodology implemented in a computer programming language for allocation of these devices in electric distribution systems based on the analytic hierarchical process (AHP) method. The main contributions focus on considering the impact of installing remotely controlled switches in the reliability indices and the AHP decision-making algorithm for the switches allocation. The effectiveness of the proposed algorithm is demonstrated with case studies involving actual systems of the AES Sul utility located in Southern Brazil.

Multicriteria decision making for management of storage energy technologies on renewable hybrid systems - the analytic hierarchy process and the fuzzy logic

Worldwide, several studies have investigated many proposals for the use of hybrid systems as alternative energy sources, operating together with energy storage technologies. Accordingly, there are large concerns about the use of appropriate methods to evaluate the application of renewable energy sources and storage energy systems. Thus, it is important to observe that the renewable hybrid systems are environmental friendly, having as consequence governmental incentives for their development in many countries, like Brazil. This paper presents a methodology taking as basis the theory developed by Saaty -- the Analytic Hierarchy Process (AHP method) - and multi-rulesbased decision and multi-sets considerations applied using fuzzy logic. By exploiting a multi-criteria decision making, this methodology evaluates the operation of storage energy systems such as: compressed air energy storage (CAES), pumped hydro storage (PHS), H2 storage, flywheel and super-capacitors. In addition, different scenarios are investigated concerning environment impacts and costs. For the purpose of the study, these five different energy storage technologies are evaluated objectifying to find the most appropriate storage energy system for different scenarios, always considering the desirable criteria, namely: efficiency, costs, technical maturity, environmental impacts, power application range and lifecycle.

Selection of storage energy technologies in a power quality scenario — the AHP and the fuzzy logic

In response to the escalating energy crisis and related pollution problems verified worldwide, it is essential to assume new energy technologies that use renewable energy sources in an efficient and environmentally friendly manner. However, widespread implementation of these sources will be more attractive only if they operate together with energy storage technologies. Besides, a successful storage energy selection is essential to deal with some mismatches among costs, efficiency and power quality constrains. This paper presents a methodology taking as basis the AHP (Analytic Hierarchy Process) and fuzzy logic. By exploiting a multi-criteria decision making, this methodology evaluates the operation of storage energy systems such as: pumped hydro storage (PHS), compressed air energy storage (CAES), H2 storage, flywheel and super-capacitors. The main objective of the study is to develop a multicriteria analysis to find the most appropriate storage energy system concerning a power quality scenario. For this, the criteria in analysis are: efficiency, load management, technical maturity, costs, lifecycle and power quality. Considerations and results described in this paper are part of the Research & Development Program undertaken by the Federal University of Santa Maria, Brazil.

Methodology for placement of Dispersed Generation Systems by analyzing its Impacts in Distribution Networks

The Brazilian electric systems need the development of new researches and tools, in order to obtain a logic solution to maintain and improve the reliability and the quality of the power delivered to customers. The study of the appropriate connection of dispersed generation sources is an essential topic to be analyzed, since this process may provide positive impacts along the feeders. The main effects of the DG operation inside a distribution system model are here analyzed through the software DigSilent®, considering power losses and voltage levels. Moreover, a multi-objective methodology - Bellman-Zadeh algorithm and membership fuzzy functions - is used for evaluating quantitative and qualitative parameters. The main objective of the paper is finding the appropriate DG placement inside a distribution system model. It is important to observe that the methodology presented in this study can be applied to distribution system feeders to find in which feeder will be the most appropriate DG location, as well to any node inside a determined feeder providing a specific place for the appropriate DG site.

Software for Automatic Coordination of Protection Devices in Distribution System

Among the several components of distribution systems, protection devices present a fundamental importance, since they aim at keeping the physical integrity not only of the system equipment, but also of the electricians team and the population in general. The existing tools today in the market that carry out the making of protection studies basically draw curves, and need direct users interference for the protection devices adjustment and coordination analyses of selectivity, being susceptible to the users mistakes and not always considering the best technical and economical application. In Brazil, the correct application of the protection devices demand a high amount of time, being extremely laborious due to the great number of devices (around 200 devices), besides the very dynamic behavior of distribution networks and the need for constant system expansion. This paper presents a computational tool developed with the objective of automatically determining the adjustments of all protection devices in the distribution networks to obtain the best technical application, optimizing its performance and making easier protection studies.

Algorithm of reliability optimization for operational planning of distribution systems

Reliability of energy supplies is considered the most important technical and economical characteristic of an electric system. The most efficient solution to increase the reliability in distribution systems, in most cases, is the rational sectioning of the networks. In that direction, the main difficulty in the formation of mathematical optimization models of reliability is the growing complexity of analytical expressions for definition of indicators to represent the system reliability. In this paper, is analyzed an approach to allow construction of objective functions and restrictions containing discreet variables, considering a set of factors such as: statistical data of faults, topology and parameters of the networks, location and characteristics of commutation equipments, etc. However, an attempt to use exact methods of discreet optimization causes an increase in the number of variables and restrictions and, as a consequence, presents insuperable computing difficulties. Therefore, it is proposed and tested a heuristic method of optimization to overcoming such difficulties.

Storage energy management with power quality concerns the analytic hierarchy process and the fuzzy logic

In view of current and foreseeable energy shortage and environmental scenario, the exploitation of renewable energy sources offer great potential to satisfy the energy lack and to decrease the dependence on fossil fuel, also reducing global warming caused by CO2 emissions. However, widespread implementation of these sources will be more attractive only if they operate together with energy storage technologies. Besides, an effective storage energy management is essential to deal with some mismatches among power quality, efficiency, costs and environmental constrains. This paper presents a methodology taking as basis the analytic hierarchy process and fuzzy multi-rules and multi-sets. By exploiting a multi-criteria decision making, this methodology evaluates the operation of energy storage systems such as: pumped hydro storage (PHS), compressed air energy storage (CAES), H2 storage, flywheel, super-capacitors, lithium-ion and NaS advanced batteries and VRB flow battery. The main objective of the study is to develop a multicriteria analysis to find the most appropriate energy storage system concerning a power quality priority. For this, the criteria in analysis are: efficiency, load management, technical maturity, costs, environment impacts and power quality. Considerations and results described in this paper are part of the Research & Development Program undertaken by the Federal University of Santa Maria, Brazil.

Assessment of the smart grids applied in reducing the cost of distribution system losses

The distribution systems need to adjust and intensify the use of new available technologies and incorporate intelligence to combat non-technical loss processes. Its detection is one of the greatest challenges to energy distribution companies. Studies and research involving load modeling or load estimation (LM/LE) on power system distribution combined with smart grid functionality will help control commercial loses in electric power distribution systems. The use of algorithms is proposed for LM/LE using monthly energy consumption data converted to hourly demand. This information and the remote monitoring consumption data via smart meters will be processed by a computational tool that will indicate the feeder with the greater probability of presenting non-technical losses, with the objective of locating energy fraud, directing companys investment on combating non-technical losses.

EMI investigation yield by single-phase PFC pre-regulators

This paper investigates the problem of electromagnetic interference (EMI) generated into power converters used to correct the power factor (PFC). The topologies discussed in this paper are the boost converter, interleaved boost and dual boost. The paths traveled by differential mode (DM) noise and common mode (CM) noise are illustrated. An analysis of the inductor parasitic capacitance impact over the conducted noise is realized. All converters were designed in a way that the total harmonic distortion (THD) of the input current be the same, in order to use the same input filter. The EMI filter designed to comply with the EMI standards and experimental results with filter are also shown.

Real-time evaluation of voltage control in distribution systems using remote measurements and smart meters

The recent technological advances included in the distribution systems, such as the use of supervisory systems, automation and the emergence of the smart meters brings many possibilities for improvement in the methodologies used in the operation of these systems. This paper proposes a methodology for using state estimation techniques and error detection in smart grids, through measures in the MV network and smart meters to evaluate the voltage profile of the feeder. This evaluation is obtained by calculating an index that analyzes the voltage levels at nodes of consumers according to the ranges appropriate, precarious and critical, further penalizing violations in loads with higher priority or that are in this condition for a long time. The methodology for evaluation can be used to predict the scenarios when changing settings in voltage regulators, seeking to supply energy with a higher quality, thereby increasing consumer satisfaction.