Impact of Power-to-Gas on distribution systems with large renewable energy penetration

The exploitation of the Power-to-Gas (PtG) technology can properly support the distribution system operation in case of large penetration of Renewable Energy Sources (RES). This paper addresses the impact of the PtG operation on the electrical distribution systems. A novel model of the PtG plant has been created to be representative of the entire process chain, as well as to be compatible with network calculations. The structure of the model with the corresponding parameters has been defined and validated on the basis of measurements gathered on a real plant. The PtG impact on the distribution systems has then been simulated on two network models representing a rural and a semi-urban environment, respectively. The testing has been carried out by defining a set of cases that contain critical situations for the distribution network, caused by RES plant placement. The objectives of the introduction of PtG are the reduction of the reverse power flow, as well as the reduction of the overcurrent and overvoltage issues in the distribution system. The results obtained from annual simulations lead to considerable reduction (from 78 to 100%) of the reverse power flow with respect to the base case, and to alleviating (or even solving) the overcurrent and overvoltage problems of the networks. These results indicate PtG as a possible solution for guaranteeing a smooth transition towards decarbonized energy systems. The capacity factors of the PtG plants largely vary depending on the network topology, the RES penetration, the number of the PtG plants and their sizes. From the test cases, the performance in a rural network (where the minimum capacity factor is about 50%) resulted better than in a semi-urban network (where the capacity factor values range between 21% and 60%)

Evaluation of the impact of heat-wave on distribution system resilience

This paper addresses the impact of heat waves on a real urban distribution system. A data-driven methodology is proposed to simulate the portion of faults that can be associated to normal conditions (and hence to reliability) and the portion correlated to the heat wave occurrence. Based on real data collected in the years 2012-2017, the fault rates associated to reliability and resilience have been calculated and then used to feed a Monte Carlo simulation aiming to manage the uncertainty in the fault occurrence. Finally, based on the Italian legislation, the avoided costs deriving by the substitution of the faulted portion of the system have been calculated. The results show the different nature of reliability and resilience in terms of empirical cumulative curve, suggesting the necessity of using a stochastic-based methodology within regulatory frameworks, especially in case of output-based regulation

Co-simulation Management Algorithm for Distribution System Operation with Real-Time Simulator

This article presents a co-simulation framework consistent with the real-time simulation for operational analysis of electrical distribution networks. Realtime simulators have become a fundamental tool for testing and optimising control strategies in a safe and controlled environment. The proposed methodology outlines the steps required for setting up, controlling, and monitoring an electrical grid using a real-time simulator. The framework proposes the use of the Message Queuing Telemetry Transport communication between the electrical grid module and an external coordinator. An algorithm based on the Python programming language is proposed to manage the real-time simulation, create the grid topology, and communicate with the external coordinator. The implementation of the electrical network and the validation of the real-time simulator network are also presented. The article concludes that the proposed framework can improve the performance and flexibility of co-simulation for studies on the penetration of power electronics-based renewable sources

Exploiting graphlet decomposition to explain the structure of complex networks: the GHuST framework

The characterization of topology is crucial in understanding network evolution and behavior. This paper presents an innovative approach, the GHuST framework to describe complex-network topology from graphlet decomposition. This new framework exploits the local information provided by graphlets to give a global explanation of network topology. The GHuST framework is comprised of 12 metrics that analyze how 2- and 3-node graphlets shape the structure of networks. The main strengths of the GHuST framework are enhanced topological description, size independence, and computational simplicity. It allows for straight comparison among different networks disregarding their size. It also reduces the complexity of graphlet counting, since it does not use 4- and 5-node graphlets. The application of the novel framework to a large set of networks shows that it can classify networks of distinct nature based on their topological properties. To ease network classification and enhance the graphical representation of them, we reduce the 12 dimensions to their main principal components. Furthermore, the 12 dimensions are easily interpretable. This enables the connection between complex-network analyses and diverse real applications

Model-based Identification of Alternative Bidding Zone Configurations from Clustering Algorithms Applied on Locational Marginal Prices

This paper deals with the application of clustering methods to assist the bidding zone review processes in Italy, considering the Locational Marginal Prices (LMPs) as the relevant features. A novel approach based on the definition of the input data for clustering, depending on a number of scenarios defined by the Transmission System Operator, is exploited. The problem under analysis requires additional procedures to solve the challenging issue of incorporating node connection constraints in the clustering algorithm. A dedicated procedure, based on the definition of specific functions, is then applied to develop customised versions of k-means and hierarchical clustering. The customised procedures implemented can identify both wide clusters and outliers, whose location depends on the assessed scenarios

Connecting in Real-time Power System Labs: An Italian Test-case

Sharing of hardware and software facilities together with knowledge and expertise among laboratories is a key point in research. In the power systems field this is possible even remotely by coupling real-time simulators located in different laboratories. In this paper an experimental test-bed is described. It consists of the remote interconnection of the realtime simulators, located at Politecnico di Torino and Politecnico di Bari respectively, in order to perform Remote Power Hardware-in-the-Loop experiments. The possibilities and limitations of this type of co-simulation are described and a case study is presented

Enquête sur la distribution du crédit aux agriculteurs dans le département du Cantal : résultats pour la période 1970-1975

Diffusion du document : INRA Station d'Economie et Sociologie rurales 65 rue de Saint-Brieuc 35042 Rennes Cedex (FRA)Cette note se réduit à une présentation commenté des premiers résultats de l'enquête menée dans le cantal. La période étudiée couvre les années 1970 à 1975. La situation structurelle des exploitations est saisie au départ par les données du RGA puis par celles de l'EPEXA en 1975. La méthode employée consiste à utiliser pour le département du Cantal, un sous-échantillon EPEXA (le taux moyen de sondage est de 1/50) dont les exploitations sont analysées tant du point de vue de leur évolution structurelle que de celui de leur endettement. Les données sur ce point ont été recueillies par l'enquête auprès de la Caisse Régionale du Cantal

Mtss1 promotes cell-cell junction assembly and stability through the small GTPase Rac1

Cell-cell junctions are an integral part of epithelia and are often disrupted in cancer cells during epithelial-to-mesenchymal transition (EMT), which is a main driver of metastatic spread. We show here that Metastasis suppressor-1 (Mtss1; Missing in Metastasis, MIM), a member of the IMD-family of proteins, inhibits cell-cell junction disassembly in wound healing or HGF-induced scatter assays by enhancing cell-cell junction strength. Mtss1 not only makes cells more resistant to cell-cell junction disassembly, but also accelerates the kinetics of adherens junction assembly. Mtss1 drives enhanced junction formation specifically by elevating Rac-GTP. Lastly, we show that Mtss1 depletion reduces recruitment of F-actin at cell-cell junctions. We thus propose that Mtss1 promotes Rac1 activation and actin recruitment driving junction maintenance. We suggest that the observed loss of Mtss1 in cancers may compromise junction stability and thus promote EMT and metastasis