Substation Power Transformer Risk Management: Reflecting On Reliability Centered Maintenance And Monitoring

The main objective of this article is to propose a methodology for prioritizing actions in predictive maintenance substation equipment, applied to Power Transformers, which are eventually responsible for the income revenue of energy companies (generation, transmission and distribution). This is a reflection on the failure analysis and risk management with optimal use of predictive maintenance, to reduce or eliminate transformer shutdowns. Using statistical concepts, this proposal goes through various stages of application, and addresses power transformer differences (generation, transmission and distribution), aspects of life cycle, operation, maintenance, aging, depreciation, aspects of reliability, risk of failure and effectiveness of predictive techniques. The basic process concept lays on stratification and consolidation of data from studies in the area of reliability centered maintenance, combined with historical information, taking also into account the diagnosis on equipment condition based on monitoring and predictive concept. © 2012 IEEE. IEEE Power and Energy Society,IEEE Uruguay SectionCarneiro, J.C., Bini, M.A., Economic aspects in the management of transformers (2008) CPFL RDEEM Technical Study Report 2008-49(2006) Study B03.01 Reliability Centered Maintenance Substation, , Cigré(2008) Working Group A02.03 Monitoring of Power Transformers, , Cigré(2008) Preventive Maintenance of Power Transformers, , Technical Guidance/CPFL 3405(2007) Periodic Inspection of Substations and Related Facilities, , Technical Guidance/CPFL 3963Carneiro, J.C., Rapid diagnosis of incipient faults in transformer substations (2010) CPFL Study Technical Report 13989(2005) Analysis and Diagnosis and Management of Predictive Maintenance of Transformers and Voltage Regulators and Substations, , Technical Guidance/CPFL 04096Carneiro, J.C., Aspects of moisture in the solid insulation of power transformers in substations (2010) CPFL Technical Report 14057, , Method of DuvalVasconcelos, V., Alves, M., Moura, G., (2008) Monitoring of Moisture from Oil Power Transformers Aiming to Increase Reliability, , (CPFL).(Treetech), (Treetech)Smith, I.P., Groups of reliability-centered maintenance case study of the electric sector (2006) CHESFCarneiro, J.C., Risk management of power transformers from substations to the explosions and fires Workshop / Working Group A2 Cigré 04 - Transformer Explosion and Fire, June 2011. Foz Do Iguaçu, PR (Itaipu Binational), , Presented at th

Consumer Loading Characterization Based On Measurement Campaigns - A Prospective Approach

This paper presents a prospective approach on how load curves can be typified using the NCEA (National Classification of the Economic Activities) instrument and also based on energy measurement campaigns commonly carried out. The proposed method intends to obtain load curves sufficiently robust, despite the available measurements may not have statistical significance. The proposed hypotesis tries to identify more representative consumer groups within a certain activity regarding parameters like the consumer class, consumption pattern, average energy, load factor and other available parameters. The results presented, pertaining here to the measurement of Group B (which according to the 1160 NCEA activity involves container manufacture, metal works, etc) indicate that these curves have the potential to replace the curves currently used in engineering (based on GIS) with data obtained through the measurement campaigns for tariff revision. © 2012 IEEE.IEEE Power and Energy Society,IEEE Uruguay SectionLoad Curve Characterization - CPFL (2007) Daimon ReportLoad Curve Established on Consumption Habits (1992) IEE/USP Report(2006) PRODIST, Module 2: Procedures for the Distribution of Electricity in the Brazilian Power Syste

Un marco conceptual para la formalización de crosscutting en desarrollos orientados a aspectos

El concepto de crosscutting suele ser descrito en términos de scattering y tangling. Sin embargo, la distinction entre estos términos no suele ser concisa, llevando a situaciones ambiguas. En muchas ocasiones se hace necesario tener definiciones más precisas, por ejemplo para determinadas áreas de investigación como la identificación formal de asuntos transversales o crosscutting concerns. Proponemos un marco de trabajo conceptual para la formalización de estos conceptos basado en lo que denominamos un patrón de crosscutting que representa la relación entre elementos de dos niveles diferentes, por ejemplo concerns y una representación de dichos concerns. Estos conceptos son definidos formalmente en términos del álgebra lineal y representados mediante matrices y operaciones con dichas matrices. De este modo, el concepto de crosscutting puede ser claramente diferenciado de los términos de scattering y tangling. La utilidad de las matrices de dependencias presentadas se ilustra mediante el análisis de crosscutting a lo largo de una serie de niveles de refinamiento, que puede ser formalizado en lo que hemos denominado la concatenación de patrones de crosscutting

Austenite reversion kinetics and stability during tempering of an additively manufactured maraging 300 steel

Reverted austenite is a metastable phase that can be used in maraging steels to increase ductility via transformation-induced plasticity or TRIP effect. In the present study, 18Ni maraging steel samples were built by selective laser melting, homogenized at 820 °C and then subjected to different isothermal tempering cycles aiming for martensite-to-austenite reversion. Thermodynamic simulations were used to estimate the inter-critical austenite + ferrite field and to interpret the results obtained after tempering. In-situ synchrotron X-ray diffraction was performed during the heating, soaking and cooling of the samples to characterize the martensite-to-austenite reversion kinetics and the reverted austenite stability upon cooling to room temperature. The reverted austenite size and distribution were measured by Electron Backscattered Diffraction. Results showed that the selected soaking temperatures of 610 °C and 650 °C promoted significant and gradual martensite-to-austenite reversion with high thermal stability. Tempering at 690 °C caused massive and complete austenitization, resulting in low austenite stability upon cooling due to compositional homogenization29CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo001573661/2008-12017/17697-5; 2008/57863-0; 2014/20844-1; 2019/00691-0UID/EMS/00667/2019FCT - Fundação para a Ciência e TecnologiaWe want to thank the Brazilian Nanotechnology National Laboratory (LNNano), CNPEM/MCTIC and Brazilian Synchrotron Light Laboratory (LNLS) CNPEM/MCTIC for the use of the SEM/EBSD and the XTMS beamline, respectively. Authors acknowledge FAPESP (2017/17697-5), FAPESP (2008/57863-0), FAPESP (2014/20844-1), FAPESP (2019/00691-0) and CNPq (573661/2008-1), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. J. P. Oliveira acknowledges Fundação para a Ciência e Tecnologia (FCT) for its financial support through the project UID/EMS/00667/2019. The chemical composition measurements were conducted at VILLARES METAL