Communication requirements for future secondary substations to enable DSO functions

Reliable and scalable communication technologies are required to securely integrate and utilise the flexibility offered by different smart grid solutions. Smart secondary substations can play a critical role in enabling the flexibility services for the DSO with more monitoring and control functions being deployed at these substations. However, there are a number of challenges associated with the deployment and integration of communications to enable future DSO functions. This paper defines the key requirements for future secondary substation communications and provides a number of recommendations to address future operator needs. A case study related to the deployment of a Smart Transformer for better utilisation of network assets and voltage regulation is presented to illustrate the applicability of aforementioned requirements

Current state of pediatric neuro-oncology imaging, challenges and future directions

Imaging plays a central role in neuro-oncology including primary diagnosis, treatment planning, and surveillance of tumors. The emergence of quantitative imaging and radiomics provided an uprecedented opportunity to compile mineable databases that can be utilized in a variety of applications. In this review, we aim to summarize the current state of conventional and advanced imaging techniques, standardization efforts, fast protocols, contrast and sedation in pediatric neuro-oncologic imaging, radiomics-radiogenomics, multi-omics and molecular imaging approaches. We will also address the existing challenges and discuss future directions

Synchronization of Low Voltage Grids Fed by Smart and Conventional Transformers

The Smart Transformer (ST) is a power electronicsbased transformer, which operates as grid-forming converter in the low voltage-fed grid. It synthesizes the voltage waveform with magnitude, phase and frequency independently from the main power system. If a meshed operation of the ST with a conventional transformer is required, to improve the power flow control and to control the voltage profile, the voltage waveforms between the two grids have to be synchronized. The switching under different voltage magnitude, phase or frequency, can lead to a large power in-rush. This work proposes a synchronization strategy that enables a seamless transition of the ST to parallel operations with conventional transformers. Differently from classical communication-based methods, this work addresses a more realistic implementation case with limited communication infrastructure. The ST relies only on local measurements and on its advanced control capability to determine the effective switch to parallel operations. The performance of the proposed strategy has been proved analytically and through simulations in a PLECS/Matlab environment, and validated experimentally by means of Power-Hardware-In-Loop (PHIL) evaluation

Synchronization of Low Voltage Grids Fed by Smart and Conventional Transformers

The Smart Transformer (ST) is a power electronicsbased transformer, which operates as grid-forming converter in the low voltage-fed grid. It synthesizes the voltage waveform with magnitude, phase and frequency independently from the main power system. If a meshed operation of the ST with a conventional transformer is required, to improve the power flow control and to control the voltage profile, the voltage waveforms between the two grids have to be synchronized. The switching under different voltage magnitude, phase or frequency, can lead to a large power in-rush. This work proposes a synchronization strategy that enables a seamless transition of the ST to parallel operations with conventional transformers. Differently from classical communication-based methods, this work addresses a more realistic implementation case with limited communication infrastructure. The ST relies only on local measurements and on its advanced control capability to determine the effective switch to parallel operations. The performance of the proposed strategy has been proved analytically and through simulations in a PLECS/Matlab environment, and validated experimentally by means of Power-Hardware-In-Loop (PHIL) evaluation

Investigating Successful International Experiences in Drought Management

Analysis of existing drought management policies in some countries, including Iran, indicates that decision-makers mainly react to drought episodes through a crisis-management approach, instead of developing a comprehensive and long-term policies. One of the comprehensive programs is the drought risk management model adopted in the member state of the European Union (EU), which is based on the EU Water Framework Directive (WFD). In the present study, the above-mentioned document along with the experiences of different countries faced with the drought crisis was analyzed in order to prepare a drought management plan for the country. This study is an applied research performed through library studies based on scientific and international resources. The results showed that in the process of drought management, creation of organizational capacity is the main factor to evaluate drought and its various effects on the community. This can only be achieved through the establishment of a Drought Independent Committee. On the other hand, drought management should be seen as a risk management process that emphasizes permanent monitoring of resources and observes climate change in the monitored area, rather than the onest of disaster as a crisis management. Drought management has been accepted by the international community in terms of risk management instead of crisis management. The proposed plan presented in this study is based on active drought management (risk management) that provides appropriate plans and preparedness for drought response, by offering long-term planning and forecasting

Transplantation of Neural Stem Cells Cultured in Alginate Scaffold for Spinal Cord Injury in Rats

Study DesignThis study investigated the effects of transplantation of alginate encapsulated neural stem cells (NSCs) on spinal cord injury in Sprague-Dawley male rats. The neurological functions were assessed for 6 weeks after transplantation along with a histological study and measurement of caspase-3 levels.PurposeThe aim of this study was to discover whether NSCs cultured in alginate transplantation improve recovery from spinal cord injury.Overview of LiteratureSpinal cord injury is one of the leading causes of disability and it has no effective treatment. Spinal cord injury can also cause sensory impairment. With an impetus on using stem cells therapy in various central nervous system settings, there is an interest in using stem cells for addressing spinal cord injury. Neural stem cell is one type of stem cells that is able to differentiate to all three neural lineages and it shows promise in spinal injury treatment. Furthermore, a number of studies have shown that culturing NSCs in three-dimensional (3D) scaffolds like alginate could enhance neural differentiation.MethodsThe NSCs were isolated from 14-day-old rat embryos. The isolated NSCs were cultured in growth media containing basic fibroblast growth factor and endothelial growth factor. The cells were characterized by differentiating to three neural lineages and they were cultured in an alginate scaffold. After 7 days the cells were encapsulated and transplanted in a rat model of spinal cord injury.ResultsOur data showed that culturing in an alginate 3D scaffold and transplantation of the NSCs could improve neurological outcome in a rat model of spinal cord injury. The inflammation scores and lesion sizes and also the activity of caspase-3 (for apoptosis evaluation) were less in encapsulated neural stem cell transplantation cases.ConclusionsTransplantation of NSCs that were cultured in an alginate scaffold led to a better clinical and histological outcome for recovery from spinal cord injury in a rat model

Multi-zone LVDC distribution systems architecture for facilitating low carbon technologies uptake

Low voltage direct current (LVDC) distribution systems have recently been considered as an alternative approach to provide flexible infrastructure with enhanced controllability to facilitate the integration of low-carbon technologies (LCTs). To date, there is no business-as-usual example of LVDC for utility applications and only few trials have been developed so far. The deployment of LVDC in general will present revolutionary changes in LV distribution networks. This will require are thinking of network design principles and the enablement of integrated solutions. This discussion paper reviews the current practice in utility-scale LVDC distribution networks worldwide. The paper also presents a new multi-zone architecture approach which can be used to better understand future of LVDC systems, and exploit their inherent flexibility to allow synergistic integration of multiple energy technologies

Quantification of transient fault let-through energy within a faulted LVDC distribution network

LV direct current (LVDC) distribution systems have recently been considered as an alternative approach to electrical distribution system infrastructure as they possess the flexibility and controllability that is required to facilitate the integration of low carbon technologies (LCT). For example, energising existing LV AC cables by DC with higher voltages (>0.4kV) can potentially release additional power capacity on LV cables and reduce the associated thermal losses. However, converting existing AC cables for DC operation may change the cable performance under faulted conditions, resulting in a change to its lifetime. The nature of future LVDC systems can be capacitive due to the characteristic of particular customers such as battery energy storage systems (BESS) and electric vehicles (EVs). A short-circuit fault on the DC side may lead to a discharge/release of significant transient energy in LV cables which was never anticipated under traditional LVAC networks. This paper quantifies the transient DC fault let-through energy which can be imposed on existing AC cables used for DC operation, and draws conclusions on the potential impact of such phenomena on the cable performance. A detailed model of an LVDC test network with three-core LV cables is developed using PSCAD/EMTDC for simulation studies