Student: GLEYSE KELLY DA SILVA

Title: PROJETO ENERGETICAMENTE EFICIENTE DE REDES ÓPTICAS OTN

Supervisor: PROF. DR. CARMELO JOSÉ ALBANEZ BASTOS FILHO

External Examiner: PROF. DR. LUIZ HENRIQUE BONANI DO NASCIMENTO

Internal Examiner: PROFA. DRA. VERUSCA SEVERO DE LIMA

Date: October 11th, 2023

Time: 08:00

Place: Online 

Abstract: 

With the evolution of communication networks and a growing demand for Internet services, there is a need for suitable infrastructure capable of providing higher transfer rates. An important consideration is the necessity to ensure the network’s survivability, especially since it is used for handling large volumes of traffic. The main goal of this thesis is to bring improvements to a resilient Optical Transport Network (OTN) design over Dense Wavelength Division Multiplexing (DWDM), considering multiple objectives. These objectives include cost minimization by reducing the number of interfaces, which is one of the most expensive components in an OTN network planning. Additionally, the thesis aims to minimize Failure Restoration Rate and energy consumption. This is crucial, particularly in telecommunications environments where data traffic is constantly increasing, and operators seek to optimize their resources. Consequently, we compare the performance of four multi-objective algorithms in the design of resilient OTN networks over DWDM, considering two different network topologies. One topology consists of four nodes and seven link bundles, while the other comprises 16 nodes and 32 link bundles. We observed that the OMOPSO and SMPSO algorithms yielded better results in terms of Hypervolume, converging first for topology 1. For topology 2, the HYPE algorithm pro- duced more satisfactory results, demonstrating that it is possible to minimize objectives through effective planning and efficient algorithms.

Keywords: Optical Networks; OTN/DWDM; Planning; Multiobjective Algorithms; Resilient; Energy Consumption.

Student: MARIANA DE MORAIS CAVALCANTI

Title: ESTUDOS DE MELHORIAS NO SUPRIMENTO ENERGÉTICO DOS SISTEMAS AUXILIARES DE SUBESTAÇÕES CONECTADAS À REDE BÁSICA

Supervisor: PROF. DR. MANOEL HENRIQUE DA NÓBREGA MARINHO

External Examiner: PROF. DR. HUGO VALADARES SIQUEIRA

Internal Examiner: PROF. DR. ROBERTO FELICIANO DIAS FILHO

Date: JUNE 28th, 2023

Time: 14:00

Place: Online -  meet.google.com/eqx-fhvp-ewv

Abstract: 

The substations (SEs) of the Basic Grid (transmission facilities that are part of the National Interconnected System with operating voltage level equal to or greater than 230 kV), must follow the Network Procedures (NP) established by the National Electric System Operator - ONS. Among these documents there is the Sub-module (2.6), which dictates the minimum requirements for the SEs and its equipment. With regard to the auxiliary services of the substations and, more specifically, to the alternating current (AC) power supply, these must have at least two power supplies, one external from the local distribution company and the other internal from the substation itself or two internal sources. In the second case, the sources must be provided through the transformer's tertiary or through a transformer dedicated for this purpose (TSA - Auxiliary Services Transformer). If none of these options are feasible for the substation under study, the agent responsible for the project should propose a solution for ONS to evaluate and, if consistent, approve. Furthermore, the substation should include a motor-generator group (GMG) with automatic startup and the capacity to feed the essential loads of the substation, in order to maintain the supply in case of a shortage in the two sources of supply. Many substations fail to comply with this sub-module and use GMG as the second main source. However, GMGs, in case of contingency, are not able to instantly supply power since they have an inertia time to come into operation. Furthermore, this solution is not environmentally friendly due to the gases emitted when the fuel is burned. Therefore, the Companhia Hidro Elétrica do São Francisco (CHESF) published the public call for RD project, under ANEEL's Research and Technological Development Program, entitled "Photovoltaic Minigeneration with Energy Storage by Batteries as an Autonomous Source of Supply of the Auxiliary Services of 230/500 kV Substations with Internal Source Restriction" to be applied at SE Messias/AL. Thus, this work developed solutions to replace the GMGs, both for the internal source and the emergency source, by more sustainable and efficient components: the Battery Energy Storage Systems (BESS), with or without the addition of a Photovoltaic (PV) system. For this, simulations were performed in the Homer Pro software and, with the results, analyses of reliability, environmental impact and financial viability. Finally, the best solution was the BESS with the PV System, being able to maintain the GMG for the case of emergency when there is only one Source, being it: external, coming from the transformer's tertiary or from the TSA.

Keywords: Milk Processing; Slow Pasteurization; Cheese Production; Thermal Solar Energy; Cooling Tower; Energetic Performance.

Student: IGINO GIORDANI DA SILVA GUERRA

Title: POTENCIAL DE APRIMORAMENTO DA PASTEURIZAÇÃO LENTA DO LEITE DEVIDO À UTILIZAÇÃO DA ENERGIA SOLAR TÉRMICA E DO RESFRIAMENTO EVAPORATIVO

Supervisor: PROF. DR. LUIS ARTURO GÓMEZ MALAGÓN

External Examiner: PROF. DR. ALCIDES CODECEIRA NETO

Internal Examiner: PROF. DR. JORNANDES DIAS DA SILVA

Date: JUNE 13th, 2023

Time: 10:00

Place: Online

Abstract: 

The State of Pernambuco contains four Local Productive Arrangements (APL), including one that encompasses 15 cities, with a hub in Garanhuns and in which milk production and dairy processing are the main economic activities. Cheese is a product derived from milk, and its initial manufacturing processes are filtration, pasteurization (heating, retention and cooling), fermentation and coagulation. To guarantee the hygienic-sanitary conditions in the brazilian enterprises, the industrialization of milk for the production of its derivatives is regulated by the Ministério da Agricultura, Pecuária e Abastecimento. Specifically for small cheese producers, the legislation allows the milk to be “slowly pasteurized” in a double-jacket tank. This tank is a reservoir with metallic surfaces that separate the milk from the working fluid and slow pasteurization is an activity that requires thermal energy to heat the milk up to 63 °C. Heat transfer to it is carried out indirectly by heating water, this temperature must be maintained for 30 minutes and then it must be cooled to 37°C so that the yeast is added and the clot formed in the tank. Typically, the small producers in the Pernambuco APL use heating systems consisting of Liquefied Petroleum Gas stoves installed below the double- jacket tank and the cooling operation is conducted by filling the tank with water at room temperature, promoting its flow in a single-pass configuration and no reuse. To improve the cheese making process, this work proposes the use of a solar thermal system to supply preheated water and a low cost cooling tower. Prototypes were tested and the complete slow pasteurization process was monitored a few times, using electronic instrumentation to measure and record process time, fluid temperatures, water flow and air humidity. From these measurements, the heat transfer rates developed and the net amounts of heat transferred were calculated to evaluate the energy performance of the operations. The results showed that the use of preheated water and the cooling tower integrated with the double-jacket tank reflects in time, fuel and water savings, giving the enterprise an increase in productivity and mitigation of operational costs and negative environmental impacts.

Keywords: Milk Processing; Slow Pasteurization; Cheese Production; Thermal Solar Energy; Cooling Tower; Energetic Performance.