Jussara Farias Fardin

Optimal Placement of Distributed Generation Units in a Distribution System with Uncertain Topologies using Monte Carlo Simulation

Abstract In the literature, several papers propose new methodologies to determine the optimal placement/sizing of medium size Distributed Generation Units (DGs), using heuristic algorithms like Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). However, in all methodologies, the optimal placement solution is strongly dependent of network topologies. Therefore, a specific solution is valid only for a particular network topology. Furthermore, such methodologies does not consider the presence of small DGs, whose connection point cannot be defined by Distribution Network Operators (DNOs). In this paper it is proposed a new methodology to determine the optimal location of medium size DGs in a distribution system with uncertain topologies, considering the particular behavior of small DGs, using Monte Carlo Simulation.

Study of combined cycle of Solid Oxide Fuel Cell with Micro Gas Turbines

Solid Oxide Fuel Cells (SOFC) present many advantages to generate electricity from natural gas, such as high efficiency, and little noise. However, the most important advantage of SOFC is its ability to operate at high temperatures. Their high operating temperature makes possible to use natural gas as fuel, so external hydrogen is not necessary for operation. In addition, in hybrid systems with cogeneration, the SOFC can be combined with micro gas turbine (MGT) to generate more power for the same amount of fuel. This cogeneration is interesting for power generation, from few kilowatts, for residences and commercial buildings, until megawatts as in plants for electric power generation, or industries. The study presented hear shows the increased efficiency when a MGT is integrated into the system to take advantage of exhaust gases of the SOFC.

Distributed Generation Energy in Relation to Renewable Energy: Principle, Techniques, and Case Studies

Abstract This chapter aims to present an overview of the distributed generation (DG) units, involving their principles and techniques. In the first part, the different DG technologies are presented, ranking DGs based on their kind of technology used to generate electricity. In the second part, optimal allocation of DGs and their impact on distribution networks are evaluated. Finally, DG management is treated, considering a scenario with smart grids and the use of demand-side management (DSM) techniques, covering smart homes and industrial environments. Along the chapter, case studies are presented to validate the proposed techniques.

Fuel Cells: History (Short Remind), Principles of Operation, Main Features, and Applications

Abstract Fuel cells are devices that convert chemical energy directly into electric energy. In its operation occurs an oxidation-reduction (redox) reaction between hydrogen and oxygen, producing water and electricity. Fuel cells work in an uninterrupted manner when fuel supply occurs continuously. They can be used in the generation of a few kilowatts to megawatts, depending on the model chosen. In addition, they do not emit greenhouse gases, do not generate noise pollution, and have a theoretical efficiency of around 83%.There are seven types of fuel cells: alkaline fuel cell, phosphoric acid fuel cell, molten carbonate fuel cell, direct methanol fuel cell, proton exchange membrane fuel cell, solid oxide fuel cell, and microbial fuel cell.

Biomass: Some Basics and Biogas

Abstract Biomass is a primary energy source used since the beginning of civilization. Besides the production of electric and thermal energy, biomass processing withdraws potentially contaminating material contributing to the preservation of the environment. This chapter will address some basic concepts to those who want to get to know this energy source and will present some biogas generation processes through anaerobic digestion based on digesters and landfill gas. It will present the current anaerobic digestion technologies based on digesters and the main methodologies used to model the methane emission potential of the landfill. The goal is to make the reader aware of the importance of this energy source, which is intrinsically related to the daily life of society, closing the cycle involving waste generation, waste transformation, energy generation, and return to society.

Educational tool for radial electrical distribution networks analysis and optimization studies involving distributed generation units

The interest in optimization problems involving distributed generation units has grown among undergraduate and graduate students since distributed generation unit connections have been encouraged around the world, requiring efficient power system analysis tools to solve them. The available open access tools are commonly focused on transmission network analysis. On the other hand, commercial tools adapted to radial networks do not allow the students to follow the intermediary calculations and learn with them. In many cases, the students have to develop their own computational tools, which is a time-consuming activity. This paper aims to fill the gap encountered by undergraduate and graduate students when they are performing their optimization problems involving distributed generation units, presenting the advantages of a new power flow tool focused on radial electrical distribution networks with high levels of unbalanced loads which require a three-phase power flow tool to be analyzed. The use of the proposed tool allows the students focus on their research, reducing the time spent on programming, and learning about power flow analysis applied to radial networks.

Distributed Generation Units as Ancillary Services Providers in a Pre Smart Grid Environment

Abstract Nowadays, ancillary services in electrical distribution networks (e. g. voltage support and reactive power control), usually provided by capacitor banks, start to be performed by distributed generation units (DGs). In this way, several papers have been studying the use of DGs as reactive power providers, and the power electronic/market regulation involved in this new scenario. However, the authors commonly consider a full implementation of Smart Grid philosophy, i. e., there are appropriate communications between DGs and distribution network operator (DNO)’s control centers, but it is not a close reality in many developing countries, due to high costs involved in their implementation. Therefore, this paper proposes a new method in order to use DGs as ancillary services providers in a short and medium-term (called in the literature Pre Smart Grid), in which there are not effective communications between DGs and control centers of DNOs. The proposed method uses a non-uniform DGs distribution, obtained from local atlas of wind, solar, hydraulic and biomass power. The methodology presented accurate results when compared with a PSO-based method, widely used to solve optimization problems, but needs a complete Smart Grid philosophy implementation to work.

Distribution networks automatic generation tool to perform statistical validations of technical planning methodologies

There is a lack of rigor in the validation process of technical planning methodologies. In general, such methodologies are tested only in one or two different case studies. Therefore, this paper proposes the creation of a tool that automatically generates feasible distribution networks in order to perform statistical validations of technical planning methodologies. Using a statistical approach through a linear random distribution and a GUI (graphical user interface) built at MATLAB, the developed tool can create feasible networks with the characteristics desired by the user, such as network length, number of branches and types of loads. The developed tool generates text output files that include all characteristics and are formatted according to a defined pattern. This tool can lead to future improvements in many areas, such as the implementation of the Smart Grid philosophy.

Analysis of financial impacts caused by pollution from thermal power plants in Brazilian public health system

Hydroelectric plants are responsible for generating about 85% of the electricity produced in Brazil. However, after a severe drought has affected the country in 2014 and 2015, the Brazilian energy matrix had a momentary change. It was necessary to dispatch thermal plants which were primarily used only to supplement power generation. Meanwhile, this type of generation plant significantly contributes to burning fossil fuels. Gas emission intensifies acid rain, global warming and is responsible for climate change, which ultimately deteriorates human health. There are many studies that correlate pollution escalation with increased hospital admissions due to respiratory and cardiovascular problems, raising the costs of public health spending. This study aims to establish a method to estimate economic advantages of solar distributed micro generation for homes concerning to the avoided amount spent by the government to mitigate negative effects, specifically pollution-related health problems, from the use of thermal plants. Finally, through a case study, this paper suggests some incentives that could be offered to citizens who had installed solar energy systems in their homes, once they would contribute to reduce public health costs.

Modeling and grid connection of a solid oxid fuel cell (SOFC) based on P-Q theory for stationary loads

This paper presents the dynamic modeling of a Solid Oxid Fuel Cell (SOFC) and the device necessary to perform its grid connection. Since there is a voltage drop with increasing load, the DC/DC Converter boosts the cells output voltage and keeps it regulated. The DC/AC inverter interfaces the DC output of the converter side with the AC grid side. In order to control the injection of active and reactive power into the grid, the inverter control is based on the p-q theory. It is also shown that the inherent slow response of the fuel cell would make it improper for sudden load changes, but the addition of power electronics makes the presented set feasible for such load behaviors. Simulation in Power System Computer Aided Design (PSCAD) helps validate the stated above, including the attempt to generate more power than the cells rated power capacity, which is taken into consideration.