Facing the emergency of COVID-19 in one of the first red zones in Italy, we would like to remark about the significant impact that this infection brought to our Departments of Pediatric Surgery/Urology in our hospital (Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milano). We hope that our message will help other hospitals facing this world emergency.COVID-19 infection exploded in China in November 2019, becoming a pandemic infection in March 2020. The majority of the National Health Systems did not expect such a dramatic scenario, but they had to adapt their systems to this new situation. Despite a reduced number of involved patients compared to adults, COVID-19 has brought changes also in the management of the pediatric population.Our System Before the Infection Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico is a general hospital with an area dedicated to neonates, children, and mothers. It counts 900 beds, with a maternal area of 320 beds and 6.000 deliveries per year. All the disciplines are represented in the hospital, including transplants and trauma. There are 58 adult ICU beds and 5 pediatric ICU beds plus 23 neonatal ICU beds.Before the infection, the Departments of Pediatric Surgery/Urology counted on average 3.000 surgical procedures in children per year, with a dedicated area of 28 beds. In the system, specialists dedicated to this assessment are 2 professors, 3 senior consultants, 4 consultants, 2 senior registrars, and 3 registrars. The Paramedic system includes 8 pediatric nurses, 7 general nurses, and 3 healthcare assistants. The departments, being in a University Hospital, count also on 3 fellows and 2 medical students. The system is also provided by dedicated anaesthetists for the area of Maternal-Children activities. All the neonatal surgical cases are admitted in a different dedicated Neonatal Department counting 58 beds (23 ICU).The Maternal-Neonatal-Pediatric Department is one of the largest in Europe. In this department many procedures of fetal surgery are performed. In particular, in our department, the first fetal treatment of spina bifida with minimal invasive approach in Europe was performed in June 2018. It is also one of the 4 departments in Europe for fetal treatment with tracheal plug for congenital diaphragmatic hernia. It is the main Italian referral center for low urinary tract obstructions and vesico-amniotic shunting.The following procedures are offered to neonates, infants, and children: elective surgery for major surgery or routine minor surgery, emergencies, oncology, and neonatal surgery. Patients are prepared with preop evaluation usually 2 weeks before the operation. Minor surgeries (65% of the procedures) are managed with day-surgery, while patients undergoing major surgery are usually admitted the day before for preparation to surgery. Major surgery records a waiting list of 35 days and a
The electrical power system is susceptible to several faults, which can cause the system to malfunction. Among these, the ones that occur in the busbars of substations stand out. The main bus of a substation can concentrate a large amount of power and many derivations to service electrical loads, making it an element of high importance for the reliability of the system. Although the buses have a low incidence of faults, they are considered critical elements of the electrical power system, as their operating output can cause a large number of forced outages. This situation makes the protection of this component of paramount importance. There are currently two widely used bus differential protection techniques: high-impedance and low-impedance bus differential protection. The second technique is more commonly used due to the possibility of sharing current transformers (CTs). However, the high cost and greater requirements for maintenance makes the differential protection of busbars in distribution or sub-transmission substations unfeasible. With the advent and implementation of the IEC 61850 standard, modern protection systems based on this standard offer significant advantages, such as lower expenses with installation, wiring, commissioning and maintenance; adaptable bus configuration; use of different CT ratios; considerably minimized susceptibility to CT saturation; lower risks of open secondary CT circuits and viability of implantation in distribution substations. The objective of this review is to present an overview of the works found in the literature on substation busbar differential protection, considering classical methods and those based on the IEC 61850 standard.
Os padrões IEEE Std C37.011-2011 (2011) e IEEE Std C37.04b-2008 (2008) são guias técnicos para a análise e a especificação de disjuntores, estabelecendo capacidades máximas para evitar a superação frente a Tensões de Restabelecimento Transitórias (TRT). Este estudo tem como objetivo avaliar o desempenho com foco na TRT de um disjuntor isolado a gás SF6 de uma subestação de 69 kV localizada em uma instalação elétrica industrial. Este trabalho é baseado nos limites operacionais estabelecidos pelas normas IEEE Std C37.011-2011 e IEEE Std C37.04b-2008 para investigar o comportamento da TRT durante curto-circuito. As simulações foram executadas através do EMTP-ATP e do seu pré-processador gráfico ATPDraw. Os resultados mostram a necessidade de se realizar uma análise de TRT detalhada durante o desenvolvimento do projeto, de forma a garantir o dimensionamento adequado do disjuntor.
The IEC 61850 standard aims at digitization substations and provides interoperability between various Intelligent Electronic Device vendors. The digitization process is accompanied by several challenges related to data transmission on the ethernet network and the protection behavior under these conditions. Among the challenges, we can mention packet loss, delay, and duplicate frame, which occurs when the merging units (publisher) transmit the sampled values and, for some reason, these packets do not reach the subscriber or are duplicated. Nowadays, most Intelligent Electronic Device manufacturers block the protection function when some sampled value packets are corrupted. The effects of blocking protection when packet loss occurs under normal operating conditions do not cause significant problems. However, when a fault occurs, the corrupted packets can cause a delay in fault clearance, causing even more damage to the grid. The purpose of this article is to present the effects of corrupted sampled values on the performance of overcurrent protection. All the evaluations were performed in real time using the hardware-in-loop simulation approach with a commercial Intelligent Electronic Device. The OP5700 hardware platform from OPAL-RT, with the library “IEC 61850 Data Integrity Manipulation”, was used. The results show that corrupted sampled value frames affect the functioning of the protections.
Visando reduzir a magnitude de corrente por enrolamento, a configuração do estator de geradores síncronos de grande porte utiliza normalmente mais de um enrolamento por fase. Nesse tipo de configuração, conhecido como fase dividida, as faltas entre espiras são de dificil detecção. Este trabalho tem por objetivo analisar diferentes esquemas de proteção contra faltas entre espiras em geradores síncronos fundamentados em medição de corrente. No total foram analisados cinco métodos de forma a apresentar as suas vantagens e desvantagens. As simulações computacionais de faltas entre espiras foram realizadas no software Hypersim que pertence ao simulador digital em tempo real OPAL-RT, sendo os algoritmos dos métodos implementados no Matlab.
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