Fault location in power distribution systems considering a dynamic load model

In the electrical power systems, load is one of the most difficult elements to be represented by an adequate mathematical model due to its complex composition and dynamic and non-deterministic behavior. Nowadays, static and dynamic load models have been developed for several studies such as voltage and transient stability, among others. However, on the issue of power quality, dynamic load models have not been taken into account in fault location. This paper presents a fault location technique based on sequence components, which considers static load models of constant impedance, constant current and constant power. Additionally, an exponential recovery dynamic load model, which is included in both the fault locator and the test system, is considered. This last model is included in order to consider the dynamic nature of the load and the performance of the fault locators under this situation. To demonstrate the adequate performance of the fault locator, tests on the IEEE 34 nodes test feeder are presented. According to the results, when the dynamic load model is considered in both the locator and the power system, performance is in an acceptable range.En los sistemas eléctricos de potencia, la carga es uno de los elementos matemáticamente más difíciles de representar debido a sucompleja composición y su comportamiento dinámico y no determinístico. Actualmente, se han desarrollado modelos estáticos y dinámicos de carga para diversos estudios, tales como estabilidad de tensión y estabilidad transitoria, entre otros. Sin embargo, en el campo de la calidad de la energía no se han tenido en cuenta los modelos dinámicos en la localización de fallas. Este artículo presenta una técnica de localización de fallas basada en componentes de secuencia, que considera modelos estáticos de impedancia constante, corriente constante y potencia constante. Además, se considera un modelo dinámico de recuperación exponencial, tanto en el localizador como en el sistema de pruebas. Este modelo se incluye para considerar la naturaleza dinámica de la carga y el desempeño de los localizadores ante esta situación. Para demostrar el desempeño adecuado del localizador de fallas, se realizaron pruebas en el sistema IEEE de 34 nodos. De acuerdo con los resultados, cuando se considera el modelo dinámico tanto en el localizador como en el sistema, el desempeño está en un rango aceptable

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Estrategia colaborativa basada en la reactancia de falla y la firma del sistema para la localización de fallas en sistemas de distribución

Acollaborative strategy for fault location in power distribution systems based on the fault impedance and the system signature, and using only single-end measurements, is presented in this paper. This strategy is useful to solve the multiple estimation of the faulted node, which is due to the presence of several laterals in the power system topology. According to the tests performed in a prototype power distribution system, considering single phase faults, phase to phase faults and three phase faults, and also using fault resistances from 0 to 40 ?, the obtained results show an average absolute error of 5,2% approximately. From the results can be concluded that this proposal is efficient to locate faults in power distribution systems.En este artículo se presenta una estrategia colaborativa para la localización de fallas en sistemas dedistribución, basada en el análisis gráfico de la impedancia de falla y en la firma del sistema, a partir de lasmedidas de tensión y corriente en solo un terminal de la línea. Esta estrategia permite resolver el problemade la múltiple estimación del nodo en falla, que se presenta debido a la topología altamente ramificada,propia de los sistemas de distribución. Según las pruebas realizadas en un sistema de distribuciónprototipo, considerando fallas monofásicas, bifásicas y trifásicas, y resistencias de falla que varían de 0 a40 ? , se obtuvieron errores absolutos promedio en la localización del 5.2% aproximadamente. Se apreciapor tanto, que la estrategia propuesta resulta muy eficiente para la localización de fallas en sistemas dedistribución

Fault location in power distribution systems considering a dynamic load model

In the electrical power systems, load is one of the most difficult elements to be represented by an adequate mathematical model due to its complex composition and dynamic and non-deterministic behavior. Nowadays, static and dynamic load models have been developed for several studies such as voltage and transient stability, among others. However, on the issue of power quality, dynamic load models have not been taken into account in fault location. This paper presents a fault location technique based on sequence components, which considers static load models of constant impedance, constant current and constant power. Additionally, an exponential recovery dynamic load model, which is included in both the fault locator and the test system, is considered. This last model is included in order to consider the dynamic nature of the load and the performance of the fault locators under this situation. To demonstrate the adequate performance of the fault locator, tests on the IEEE 34 nodes test feeder are presented. According to the results, when the dynamic load model is considered in both the locator and the power system, performance is in an acceptable range

Fault location in power distribution systems considering a dynamic load model

In the electrical power systems, load is one of the most difficult elements to be represented by an adequate mathematical model due to its complex composition and dynamic and non-deterministic behavior. Nowadays, static and dynamic load models have been developed for several studies such as voltage and transient stability, among others. However, on the issue of power quality, dynamic load models have not been taken into account in fault location. This paper presents a fault location technique based on sequence components, which considers static load models of constant impedance, constant current and constant power. Additionally, an exponential recovery dynamic load model, which is included in both the fault locator and the test system, is considered. This last model is included in order to consider the dynamic nature of the load and the performance of the fault locators under this situation. To demonstrate the adequate performance of the fault locator, tests on the IEEE 34 nodes test feeder are presented. According to the results, when the dynamic load model is considered in both the locator and the power system, performance is in an acceptable range. \u

XV International Congress of Control Electronics and Telecommunications: "The role of technology in times of pandemic and post-pandemic: innovation and development for strategic social and productive sectors"

La anterior selección, motivados por la aseveración de Manuel Castells -hace casi 20 años ya- que la innovación y la difusión de la tecnología parecía ser la herramienta apropiada para el desarrollo en la era de la información. Este 2020, sin embargo, ante la situación disruptiva que aquejó y aqueja a la sociedad red como una estructura social emergente de la Era de la Información basada en redes de producción, energizadas por el poder y la experiencia; falló y debe reencontrar su rumbo. Es así que los problemas acuciantes, ahora, fueron: la atención sanitaria y la superación de la epidemia de Sars Cov 2; tomó forma la, hasta entonces, visión irrealista de Castells que … no podemos avanzar con nuestros modelos de desarrollo actual, destruyendo nuestro entorno y excluyendo a la mayor parte de la humanidad de los beneficios de la revolución tecnológica más extraordinaria de la historia, sin sufrir una devastadora reacción por parte de la sociedad y la naturaleza. Fue así que el Cuarto Mundo, específicamente, donde la suficiencia de recurso humano, de capital, trabajo, información y mercado -vinculados todos a través de la tecnología- supuso que atendería eficazmente a través de la población que podía por su capacidad hacer uso racional y profesional del conocimiento, las necesidades de la mayoritaria población vulnerable y vulnerada. Por lo anterior, poner en el centro a las personas, en entornos de tarea y trabajo globales hiperconectados combinando espacios físicos, corrientes de información con canales de conexión expeditos, y formando profesionales del conocimiento que asuman y afronten los retos derivados de la transformación digital de empresas, universidades, y organizaciones, pero en condiciones de equidad y sujetos de prosperidad, será el desafío en los escenarios presentes y futuros inmediatos.The previous selection, motivated by the assertion of Manuel Castells -almost 20 years ago- that innovation and diffusion of technology seemed to be the appropriate tool for development in the information age. This 2020, however, in the face of the disruptive situation that afflicted and continues to afflict the network society as an emerging social structure of the Information Age based on production networks, energized by power and experience; He failed and must find his way again. Thus, the pressing problems now were: health care and overcoming the Sars Cov 2 epidemic; Castells' until then unrealistic vision took shape that... we cannot advance with our current development models, destroying our environment and excluding the majority of humanity from the benefits of the most extraordinary technological revolution in history, without suffering a devastating reaction from society and nature. It was thus that the Fourth World, specifically, where the sufficiency of human resources, capital, work, information and market - all linked through technology - meant that it would serve effectively through the population that could, due to its capacity, make rational use. and knowledge professional, the needs of the majority vulnerable and vulnerable population. Therefore, putting people at the center, in hyperconnected global task and work environments, combining physical spaces, information flows with expedited connection channels, and training knowledge professionals who assume and face the challenges derived from the digital transformation of companies, universities, and organizations, but in conditions of equality and subject to prosperity, will be the challenge in the present and immediate future scenarios.Bogot

Revista Temas Agrarios Volumen 26; Suplemento 1 de 2021

1st International and 2nd National Symposium of Agronomic Sciences: The rebirth of the scientific discussion space for the Colombian Agro.1 Simposio Intenacional y 2 Nacional de Ciencias Agronómicas: El renacer del espacio de discusión científica para el Agro colombiano

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research