Hybrid AC/DC Provisional Microgrid Planning Model Considering Converter Aging

Building integrated photovoltaics is one of the key technologies when it comes to electricity generation in buildings, districts or urban areas. However, the potential of building façades for the BIPV system, especially in urban areas, is often neglected. Façade-mounted building integrated photovoltaics could contribute to supply the energy demand of buildings in dense urban areas with economic feasibility where the availability of suitable rooftop areas is low. This paper deals with the levelised cost of electricity (LCOE) of building integrated photovoltaic systems (BIPV) in the capitals of all the European member state countries plus Norway and Switzerland and presents a metric to investigate a proper subsidy or incentive for BIPV systems. The results showed that the average LCOE of the BIPV system as a building envelope material for the entire outer skin of buildings in Europe is equal to 0.09 Euro per kWh if its role as the power generator is considered in the economic calculations. This value will be 0.15 Euro per kWh if the cost corresponding to its double function in the building is taken into the economic analysis (while the average electricity price is 0.18 Euro per kWh). The results indicate that the BIPV generation cost in most case studies has already reached grid parity. Furthermore, the analysis reveals that on average in Europe, the BIPV system does not need a feed-in tariff if the selling price to the grid is equal to the purchasing price from the grid. Various incentive plans based on the buying/selling price of electricity from/to the main grid together with LCOE of the BIPV systems is also investigated. View Full-TextpublishedVersio

Improved Dual-Output Step-Down Soft-Switching Current-Fed Push-Pull DC-DC Converter

Multi-port DC-DC converters are gaining more significance in modern power system environments by enabling the connection of multiple renewable energy sources, so the efficient operation of these converters is paramount. Soft switching methods increase efficiency in DC-DC converters and increase the reliability and lifespan of devices by relieving stress on components. This paper proposes a method for soft-switching of a dual-output step-down current-fed full-bridge push-pull DC-DC converter. The converter enables two independent outputs to supply different loads. The topology achieves zero-current switching on the primary side and zero-voltage switching on the secondary side, eliminating the need for active-clamp circuits and passive snubbers to absorb surge voltage. This reduces switching losses and lower voltage and current stresses on power electronic devices. The paper thoroughly investigates the proposed converter's operation principle, control strategy, and characteristics. Equations for the voltage and current of all components are derived, and the conditions for achieving soft switching are calculated. Simulation results in EMTDC/PSCAD software validate the accuracy of the proposed method.Comment: 2023 55th North American Power Symposium (NAPS

Flexible Transmission: A Comprehensive Review of Concepts, Technologies, and Market

As global concerns regarding climate change are increasing worldwide, the transition towards clean energy sources has accelerated. Accounting for a large share of energy consumption, the electricity sector is experiencing a significant shift towards renewable energy sources. To accommodate this rapid shift, the transmission system requires major upgrades. Although enhancing grid capacity through transmission system expansion is always a solution, this solution is very costly and requires a protracted permitting process. The concept of flexible transmission encompasses a broad range of technologies and market tools that enable effective reconfiguration and manipulation of the power grid for leveraged dispatch of renewable energy resources. The proliferation of such technologies allows for enhanced transfer capability over the current transmission network, thus reducing the need for grid expansion projects. This paper comprehensively reviews flexible transmission technologies and their role in achieving a net-zero carbon emission grid vision. Flexible transmission definitions from different viewpoints are discussed, and mathematical measures to quantify grid flexibility are reviewed. An extensive range of technologies enhancing flexibility across the grid is introduced and explored in detail. The environmental impacts of flexible transmission, including renewable energy utilization and carbon emission reduction, are presented. Finally, market models required for creating proper incentives for the deployment of flexible transmission and regulatory barriers and challenges are discussed

A Review of Economic Incentives for Efficient Operation of Flexible Transmission

The growing penetration of renewable energy requires upgrades to the transmission network to ensure the deliverability of renewable generation. As an efficient alternative to transmission expansion, flexible transmission technologies, whose benefits have been widely studied, can alleviate transmission system congestion and enhance renewable energy integration. However, under the current market structure, investments for these technologies only receive a regulated rate of return, providing little to no incentive for efficient operation. Additionally, a regulated rate of return creates an incentive for building more transmission lines rather than efficient utilization of the existing system. Therefore, investments in flexible transmission technologies remain rather limited. To facilitate the deployment of flexible transmission, improve system efficiency, and accommodate renewable energy integration, a proper incentive structure for flexible transmission technologies, compatible with the current market design, is vital. This paper reviews the current market-based mechanisms for various flexible transmission technologies, including impedance control, dynamic line rating, and transmission switching. This review pinpoints current challenges of the market-based operation of flexible transmission and provides insights for future endeavors in designing efficient price signals for flexible transmission operation.Comment: 2023 55th North American Power Symposium (NAPS

Hybrid AC/DC Provisional Microgrid Planning Model Considering Converter Aging

Building integrated photovoltaics is one of the key technologies when it comes to electricity generation in buildings, districts or urban areas. However, the potential of building façades for the BIPV system, especially in urban areas, is often neglected. Façade-mounted building integrated photovoltaics could contribute to supply the energy demand of buildings in dense urban areas with economic feasibility where the availability of suitable rooftop areas is low. This paper deals with the levelised cost of electricity (LCOE) of building integrated photovoltaic systems (BIPV) in the capitals of all the European member state countries plus Norway and Switzerland and presents a metric to investigate a proper subsidy or incentive for BIPV systems. The results showed that the average LCOE of the BIPV system as a building envelope material for the entire outer skin of buildings in Europe is equal to 0.09 Euro per kWh if its role as the power generator is considered in the economic calculations. This value will be 0.15 Euro per kWh if the cost corresponding to its double function in the building is taken into the economic analysis (while the average electricity price is 0.18 Euro per kWh). The results indicate that the BIPV generation cost in most case studies has already reached grid parity. Furthermore, the analysis reveals that on average in Europe, the BIPV system does not need a feed-in tariff if the selling price to the grid is equal to the purchasing price from the grid. Various incentive plans based on the buying/selling price of electricity from/to the main grid together with LCOE of the BIPV systems is also investigated. View Full-Tex

Impacts of Variable-Impedance-Based Power Flow Control on Renewable Energy Integration

The electric power grid has evolved significantly over the past two decades in response to climate change. Increased levels of renewable energy generation, as a prominent feature of this evolution, have led to new congestion patterns in the transmission network. The transmission system is originally designed for conventional energy sources, with predictable flow patterns. Insufficient transfer capability in congested transmission systems results in commitment of more expensive power plants and higher levels of renewable energy curtailment. One way to mitigate congestion is adoption of power flow control through variable-impedance flexible ac transmission system (FACTS) devices. In this paper the impacts of power flow control on generation cost, carbon emissions and renewable energy curtailment are studied under a wide range of scenarios, including generation mix from major US regional transmission organizations, and different load curves, representing seasonal variations. A two-stage stochastic unit commitment, including FACTS adjustment, is used to evaluate the impacts of FACTS devices on various types and penetration levels of renewable energy. The results show that FACTS installation effectively reduces generation cost, carbon emissions, and renewable energy curtailment. Location of renewable energy resources, peak-hour demand and the system's generation mix are among the influential factors

Retracted: Internet of things in the management of chronic diseases during the COVID‐19 pandemic: A systematic review

Abstract Introduction The use of new technologies such as the Internet of Things (IoT) in the management of chronic diseases, especially in the COVID pandemics, could be a life‐saving appliance for public health practice. The purpose of the current study is to identify the applications and capability of IoT and digital health in the management of the COVID‐19 pandemic. Methods This systematic review was conducted by searching the online databases of PubMed, Scopus, and Web of Science using selected keywords to retrieve the relevant literature published until December 25th, 2021. The most relevant original English studies were included after initial screening based on the inclusion criteria. Results Overall, 18 studies were included. Most of the studies reported benefits and positive responses in the form of patients' and healthcare providers' satisfaction and trust in the online systems. Many services were provided to the patients, including but not limited to training the patients on their conditions; monitoring vital signs and required actions when vital signs were altered; ensuring treatment adherence; monitoring and consulting the patients regarding diet, physical activity, and lifestyle. Conclusion IoT is a new technology, which can help us improve health care services during the COVID‐19 pandemic. It has a network of various sensors, obtaining data from patients. We have found several applications for this technology. Future studies can be conducted for the capability of other technologies in the management of chronic diseases

Retracted: Prenatal and neonatal complications of COVID‐19: A systematic review

Abstract Background and Aims The outbreak of coronavirus disease 2019 (COVID‐19) over the past year has affected public health worldwide. During pregnancy, the maternal immune system and inflammatory responses are widely suppressed. Pregnancy‐related immune system suppression could make the mother vulnerable to infectious diseases like SARS‐COV‐2. However, current data suggest little to no possibility of COVID‐19 transmission in pregnant women to the fetus during pregnancy or childbirth. This systematic review focused on the possible complications of COVID‐19 infection in the fetus and newborn babies including the possibility and evidence of vertical transmission by reviewing articles published during the first year of the COVID‐19 pandemic. Methods We conducted a systematic search using keywords on PubMed, Embase, and Scopus databases. The studies followed a title/abstract and a full‐text screening process, and the eligible articles were included in the study. Results In total, 238 published papers were identified using a systematic search strategy (44 articles met the inclusion criteria and were included in the final review). In all studies, a total of 2375 women with signs and symptoms of COVID‐19, who were in the second and third trimester of pregnancy, were assessed mild to moderate pneumonia was one of the most common symptoms. Seventy‐three percent of the women did not present any comorbidity, 19% had a fever, 17% had to cough as the most frequent clinical signs and symptoms, 7.5% had pulmonary changes with chest scans, 8% had increased C reactive protein, and 9.4% had decreased lymphocytes (lymphocytopenia). A total of 2716 newborns and fetal were assessed; the delivery method of 1725 of them was reported, 913 (53%) through C‐section delivery, and 812 through normal vaginal delivery (47%). Of total newborns, 13 died (five died along with the mother), and 1965 were tested for SARS‐CoV‐2:118 tested positive. In a study, vertical transmission in seven cases was reported in total of 145 cases assessed. Conclusion It appeared that most pregnant COVID patients were mildly ill, and there is currently no convincing evidence to support the vertical transmission of COVID‐19 disease. Therefore, neonates do not represent any additional risk for adverse outcomes neither during the prenatal period nor after birth

Reinfection risk of novel coronavirus (CoVID-19): A systematic ‎review of current evidence

International audienceThere is recently a concern regarding the reinfection and reactivation of previously reCoVered coronavirus disease 2019 (CoVID-19) patients