Reference Network Model Research Articles

A large-scale high-resolution geographic analysis of impacts of electric vehicle charging on low-voltage grids

Electric vehicles enable the decarbonization of the transportation sector. Yet, system implications of fully electrified private transportation on national low-voltage grids are still unknown. This study presents a geographic analysis of power system violations on a synthetically generated version of the Swedish low-voltage grid due to home charging of private passenger electric vehicles using different charging strategies. We link a national energy system model with a reference network model that together generate low-voltage proxy grids within each inhabited km2 of Sweden. We produce the first national coverage of electric vehicle charging impacts in residential areas. Our results show that the risk of power system violations due to electric vehicle charging are largest in cities and smaller in urban areas, while rural areas show significantly fewer violations. We also find that an electricity price optimized charging strategy primarily increases the risk of low-voltage power system violations in some city areas. In addition, we find large variations in power system violations in each of Sweden's four price areas. Direct charging is preferable in the far north while price optimized charging is preferable in the far south. The results show variations in impacts on distribution system operators from national low-cost renewable energy systems depending on their geographical location. The findings show important connections between national energy system models and local low-voltage grid violations.

Soft Sensing Image Analysis and Processing Method of Substation Equipment Defects

Under the background of incentive regulation of distribution companies, reference network model can be used as a valuable tool to evaluate its effective cost. These models must plan large-scale distribution areas with different voltage levels. This paper describes a green space planning algorithm for optimizing the location, size and power supply area of RNM medium and low voltage substations. In this paper, from two aspects of “environment-friendly” substation and the importance of implementing “resource-saving” substation in China, the “environment-friendly” and “environment-friendly” are studied. The results show that feature 1 is 0.363, feature 2 is 0.835, feature 3 is 0.824.

Assessment of the impact of a fully electrified postal fleet for urban freight transportation

The progressive electrification of urban distribution fleets, motivated by the consolidation of electric vehicle technology and by the mobility advantages that cities grant to non-polluting vehicles, poses future challenges that affect electrical distribution networks. This paper simulates the main last mile distribution models that can be adopted in a mega-city such as Madrid. In particular, the impact of carrying out the full load of the last mile distribution by means of electric vehicles is analyzed. Two fundamental aspects are studied, the efficiency of the different routes developed by each transport vehicle and the impact that these routes have in the electrical distribution network. For this purpose, an intelligent route planner, capable of optimizing the distribution of the load among the number of vehicles available in each postal service hub (PSH), is combined with a Reference Network Model that designs and expands the distribution network to supply consumers and electric vehicles. Several scenarios in terms of location and segmentation of postal service hubs are analyzed. From this analysis, it is concluded that reinforcements on the distribution network are avoided if the operation is decentralized (using fourteen PSHs), since a centralized operation (a single PSH) would require longer routes with higher energy consumption. Moreover, decentralized operation would enhance the emissions reduction achieved by electrifying the fleet, since the estimated absolute emissions of the electrified fleet for a decentralized scenario are up to 50% lower compared to a centralized one. Finally, the results reveal that smart charging strategies also contribute to lessen the incremental costs in the distribution network, in addition to significantly reducing the cost of energy supply.

METHOD OF MANAGING ROUTING OF DATA FLOWS IN HETEROGENEOUS NETWORKS UNDER CONFLICT, UNCERTAINTY AND DISTURBANCE

This paper proposes a method of synthesis of data transmission routes in conflicting heterogeneous self-organized wireless data networks under external and internal influences. In this case, routing is understood as the process of determining in a data transmission network one or a set of routes (pathspaths) , that are optimal within the selected criteria between a given pair or set of network nodes. Thus, a route is a sequence of network nodes and data transmission paths that connect a pair of network nodes for communication. The method is based on a mathematical model of the data network operation in a virtual multidimensional parameter space. The model of operation is based on a graph-model of information interaction of network nodes in the process of data transmission between receptor nodes and acceptors in the transmission of data streams. Based on the problem statement, the price function is formally defined as the value of the virtual distance between the nodes of a heterogeneous data network. In contrast to the Floyd-Warshall and Dijkstra algorithms, the synthesis of the data transmission route takes into account both the load of the computing environment of network nodes and the state of information interaction channels of network nodes, as well as possible changes in network parameters during data transmission. The data transmission network is self-organized, has no dedicated nodes, which ensures its reliability under external and internal influences, conflicts in data transmission, as well as variable topology. The proposed method for synthesizing data transmission routes when controlling the routing of data flows in heterogeneous networks is focused on the possibility of implementing the basic model of open systems interaction within the framework of existing protocols - the OSI model, which is a reference network model for communications and the development of network protocols.

Применение машинного обучения в защите веб-приложений

Security of network systems has become a necessity, as more and more important information is stored and used online. The spread of web applications opens up new attack vectors. Traditional security mechanisms, such as firewalls, are not designed to protect web applications and therefore do not provide adequate protection. Current attacks cannot be prevented only by blocking ports 80 (HTTP) and 443 (HTTPS). Preventative measures (such as web application firewall rules) are not always possible. Signature methods for detection are always behind the actual event. Protocol-enforced network firewalls usually provide the first line of defense, delaying most major attacks on the network perimeter. They mainly work on the network, session, and transport layers of the reference network model (OSI). Developers have significantly expanded the capabilities of network firewalls to control the integrity of a wide range of top-level protocols, such as DNS, FTP, HTTP, SMTP, and TFTP. Standard firewalls can help restrict or allow access to network ports. Although application proxy firewalls exist, they cannot understand the specific content of all web applications run by an enterprise. The purpose of this article is to study the features of using machine learning in web application protection. Methods of web application security and learning neural networks were studied. The result of this work is a theoretical overview of the neural network security of a web application.

Complex methodology of parameters management of military radio networks in the conditions of uncertainty of the radioelectronic situation

The experience of the Joint Forces operation (Anti-terrorist operation in Donetsk and Luhansk oblasts) shows that the current order of management of military radio communication systems does not always meet the modern requirements for them. The classic centralized approach to the management of channel and network resources of military radio systems does not quite meet modern requirements, so the authors of this article proposed to take mobile self-organizing networks as a basic principle of construction. The authors propose a comprehensive method of managing the parameters of military radio networks in conditions of uncertainty of the electronic environment, the essence of which is to ensure the maintenance of the specified values of the performance of military radio communication systems at the appropriate level. The article is based on the control principle, which is described in the reference network model of open systems interaction, but with some additions and changes. This approach generally allows for end-to-end management of channel and network resources of military radio systems in a complex electronic environment. In the article, the device of fuzzy logic, the theory of electronic suppression, neural networks, the theory of noise protection, the theory of antennas, noise-resistant coding are used. The proposed complex methodology should be used in the development of software for modules (units) for the assessment of advanced radio communications, based on open architecture interfaces version SCA 2.2, which will: use effective signal-code structures to ensure noise immunity of channels; to ensure efficient use of the radio frequency resource of programmable radio communication means; increase the speed of evaluation of communication channels; reduce the use of computing resources of radio communications with programmable architecture.

Building Large-Scale U.S. Synthetic Electric Distribution System Models

Rapid increases in distributed energy resources on distribution systems are prompting research efforts to improve and evaluate electric power distribution algorithms; however, there is a shortage of realistic, large-scale, U.S.-style test systems for the evaluation of such advanced algorithms. Some available tools to build large-scale test systems are of European style, and their application to studies focused on the United States might not be desirable given very different characteristics between the European and U.S. distribution designs. Motivated by this need, this paper develops detailed algorithms to build large-scale U.S. distribution systems and incorporates them in a new Reference Network Model, RNM-US. The approach starts with information from street maps and a catalog with electric equipment that includes power lines, transformers, voltage regulators, capacitors, and switching devices. The paper presents the algorithms through an illustrative case study of the different steps that comprise the process of building a synthetic distribution grid. Finally, the paper presents a medium- and a large-scale data set covering 10 million electrical nodes and 120,000 km of power lines, demonstrating the applicability of the proposed method to build very large-scale synthetic distribution systems.

Phase-selection algorithms to minimize cost and imbalance in U.S. synthetic distribution systems

The increasing penetration of distributed energy resources (DERs) has driven a push toward new algorithms and tools for distribution system operation and planning; however, there is a lack of publicly available electrical distribution test systems at the large scale—multi-feeder, multi-substation—which are required for realistically evaluating the performance and scalability of these new developments. This paper presents a Reference Network Model (RNM) aimed to plan large-scale, U.S.-style, synthetic distribution systems. Special emphasis is placed on two algorithms that allow multi-phase feeder design: (1) a method to select the most suitable number of phases for each section considering the connected customers, and (2) a method to assign phases to the users to provide near-balanced phasing while maintaining realistic levels of imbalance. The performance of the developed algorithms is verified by comparing the obtained system designs with the original IEEE 8,500-node test feeder and the Electric Power Research Institute (EPRI) J1 feeder.

A comprehensive techno-economic assessment of the impact of natural gas-fueled distributed generation in European electricity distribution networks

This paper combines three models:, an energy simulator (eQuest), the Distributed Energy Resources Customer Adoption Model (DER-CAM), and a Reference Network Model (RNM), to quantify the impact of natural gas-fueled distributed generation (NGDG) in electricity distribution networks. First, eQuest is used to determine the energy profile of each type of building. Then, DER-CAM determines the optimal planning and operation of distributed energy resources. Finally, the hourly profiles of all buildings are processed by RNM to assess the impact of NGDG integration in electricity distribution networks. The reason behind this multi-level approach is that prosumers manage distributed energy resources to maximize their benefits, and later these decisions have an impact upon the electricity distribution networks. We assess this impact. The RNM evaluates power flows to size the network components, and determines the new components required, quantifying the corresponding investments in terms of low and medium voltage network and medium to low voltage transformers. We use this methodology to analyze the sensitivity of network reinforcements to NGDG penetration. Six European networks for urban and semi-urban distribution areas in Germany, Italy, and France have been studied. The results show clear differences in the expected impact in each of these countries. They depend greatly on the level of NGDG penetration and selected network, with network costs ranging up to 150€ and savings of 900€ per building. Energy losses decrease for low NGDG penetration levels and can double at 100% NGDG penetration levels.

Two-Stage Stochastic Approach for Reference Network Considering Uncertain Reliability

With the increasing load level in the future, the optimal capacity of each transmission line is an important factor which can protect the power systems with contingency events. In this paper, a two-stage stochastic model is proposed to determine the optimal transmission line capacities based on reference network model , in which the generators and loads are the same as those in the existing transmission system and the expected interruption cost (EIC) under contingency events should be respected. It can guide the transmission network planning. The objective function is to minimize the generation cost, the investment cost of transmission lines and the EIC. In the first-stage, the initial power flow and generated output without contingency events is calculated. In the second-stage, the optimal line flow and generated output under contingency events is calculated. The large-scale problem can be divided into two parts: 1) the master problem; 2) a series of sub problems considering contingency. So the model can be solved by using a decomposed algorithm based on Bender’s decomposition. The model was applied to IEEE 118-node system for verification and efficiency.

Single-cell characterization of haematopoietic progenitors and their trajectories in homeostasis and perturbed haematopoiesis.

The dynamics of haematopoietic stem cell differentiation and the hierarchy of oligopotent stem cells in the bone marrow remain controversial. Here we dissect haematopoietic progenitor populations at single cell resolution, deriving an unbiased reference model of transcriptional states in normal and perturbed murine bone marrow. We define the signature of the naive haematopoietic stem cell and find a continuum of core progenitor states. Core cell populations mix transcription of pre-myeloid and pre-lymphoid programs, but do not mix erythroid or megakaryocyte programs with other fates. CRISP-seq perturbation analysis confirms our models and reveals that Cebpa regulates entry into all myeloid fates, while Irf8 and PU.1 deficiency block later differentiation towards monocyte or granulocyte fates. Our transcriptional map defines a reference network model for blood progenitors and their differentiation trajectories during normal and perturbed haematopoiesis.

Improved Regulatory Approaches for the Remuneration of Electricity Distribution Utilities with High Penetrations of Distributed Energy Resources

Under increasing penetration of distributed resources, regulators and electricity distribution utilities face greater uncertainty regarding the evolution of network uses and efficient system costs. This uncertainty can threaten revenue adequacy and challenges both cost of service/rate of return and incentive/performance-based approaches to the remuneration of distribution utilities. To address these challenges, this paper proposes a novel methodology to establish allowed utility revenues over a multi-year regulatory period. This method combines several “state of the art” regulatory tools designed to overcome information asymmetries, manage uncertainty, and align incentives for utilities to cost-effectively integrate distributed energy resources while taking advantage of opportunities to reduce system costs and improve performance. We use a reference network model to simulate a large-scale urban distribution network, demonstrate the practical application of this regulatory method, and illustrate its performance in the face of both benchmark and forecast errors.

EColiCore2: a reference network model of the central metabolism of Escherichia coli and relationships to its genome-scale parent model

Genome-scale metabolic modeling has become an invaluable tool to analyze properties and capabilities of metabolic networks and has been particularly successful for the model organism Escherichia coli. However, for several applications, smaller metabolic (core) models are needed. Using a recently introduced reduction algorithm and the latest E. coli genome-scale reconstruction iJO1366, we derived EColiCore2, a model of the central metabolism of E. coli. EColiCore2 is a subnetwork of iJO1366 and preserves predefined phenotypes including optimal growth on different substrates. The network comprises 486 metabolites and 499 reactions, is accessible for elementary-modes analysis and can, if required, be further compressed to a network with 82 reactions and 54 metabolites having an identical solution space as EColiCore2. A systematic comparison of EColiCore2 with its genome-scale parent model iJO1366 reveals that several key properties (flux ranges, reaction essentialities, production envelopes) of the central metabolism are preserved in EColiCore2 while it neglects redundancies along biosynthetic routes. We also compare calculated metabolic engineering strategies in both models and demonstrate, as a general result, how intervention strategies found in a core model allow the identification of valid strategies in a genome-scale model. Overall, EColiCore2 holds promise to become a reference model of E. coli’s central metabolism.

Economic benefits of integrating Active Demand in distribution network planning: A Spanish case study

The recent advances in smart metering and communication technologies in electricity distribution networks could bring new opportunities to distribution system operators (DSOs). In particular, new forms of Active Demand (AD) could be developed to help DSOs to alleviate network congestions and decrease peak capacity requirements, which could in turn reduce or postpone the need for network reinforcements. This paper explores the mechanisms that would allow DSOs to incorporate AD procedures into their network planning strategies. A Reference Network Model (RNM) is used to quantify the potential economic benefits that AD could bring to distribution grids. The analysis is supported by a case study of two rural and urban areas of Spain, based on realistic large-scale exemplary networks and real consumption data.

Distribution planning with hourly profiles for analysing electric vehicle charging strategies

This paper analyses the impact of plug-in electric vehicles (PEVs) on distribution networks. The reference network model (RNM) is used to model the grids and to carry out sensitivity analysis for several scenarios. The set of scenarios selected includes PEV penetration levels, charging strategies and location distributions. Each scenario is characterised in terms of the number of electric vehicles, the vehicles' class, technical parameters and charging time. Five large-scale real distribution networks are modelled and analysed. The topologies selected are intended to be representative of some typical European distribution networks. Results show that the charging strategies are critical. At least, new multi-tariff schemes should be established to encourage charging at valley hours. Depending on the PEV location distribution, smart charging may also be necessary to reduce the distribution network costs further.

Electricity distribution tariffs and distributed generation: Quantifying cross-subsidies from consumers to prosumers

An increasing amount of distributed generation (DG) can cause an increase or a decrease on distribution network costs. Tariff design is the main tool for allocating these costs to customers who own and operate DG resources.Currently, however, either DG units are exempt from paying distribution tariffs or they are subject to tariffs originally designed according to a traditional pricing model without DG in the grids, also known as load-based pricing. Partial recovery of the allowed distribution company revenue requirements or cross-subsidies between customers may ensue from such tariff arrangements.In this article, pricing, as represented by a combination of net metering and pure volumetric tariffs, is applied in the context of increasing DG. The paper presents a methodology where a Reference Network Model (RNM) is used to investigate the effect of this pricing scheme on the magnitude of cross-subsidies from consumers towards the so-called prosumers for a set of twelve simulations based on real-size networks in the U.S.For the considered scenarios, the analysis reveals substantial cross-subsidies from consumers toward prosumers. The degree of subsidy varies with the amount of DG connected to the grid and network characteristics. The rate of cross-subsidy tends to be higher for low-density grids.This paper contributes to the net metering literature with a quantitative assessment of cross-subsidies by comparing allocated payments to different actors with the costs they impose on the system, estimated through an RNM. Moreover, the paper proposed a tariff structure based on cost causality by proposing a cost-reflective, volumetric tariff approach through which aggregate load-driven and DG-driven network costs are accordingly allocated to loads and DG units.

Optimal investment in smart MV/LV substations to improve continuity of supply

Smart MV/LV substations will play a crucial role in the evolution towards a smarter distribution grid. The implementation of smart MV/LV substations can provide a significant improvement of continuity of supply. However, a large investment is required, so the optimal level of implementation must be found. This paper aims to provide a methodology to determine the optimal degree of automation comparing the costs of increasing automation to the benefits derived from the improvement of continuity of supply achieved. First, the impact of different degrees of implementation of smart MV/LV substations on continuity of supply is quantified using a reference network model (RNM). Then, an economic analysis is performed to assess automation costs and supply interruptions costs from two different perspectives, considering non supplied energy for network users and alternatively regulatory incentives for distribution companies. Finally, the optimal degree of automation is identified by comparing marginal costs. Furthermore, the methodology proposed is applied to two large scale test cases of an urban and a semi-urban network. The results obtained highlight the need to compare costs and benefits showing that there is indeed an optimal degree of automation different from the complete automation of the distribution system.

An approach to calibrate incentives for continuity of supply in the Spanish electricity distribution system

This paper proposes an approach to calibrate incentives for continuity of supply in electricity distribution in Spain. This approach consists on the estimation of the impact of continuity of supply improvements on distribution network costs. For this purpose, distribution costs resulting from different continuity of supply requirements are computed by a reference network model (RNM). The results obtained from the RNM are used to estimate a cost-function that considers continuity of supply a cost driver for distribution costs. This methodology is applied to three Spanish areas of service (an urban one, a semi-urban one and a rural one) in such a way that differences in distribution costs caused by the characteristics of the area type can be taken into account. The analysis indicated that distribution costs are more sensitive to continuity of supply improvements in rural areas of service. It also demonstrated that the incentive for reducing number of service interruptions should be higher than the incentive for reducing duration of service interruptions. Finally, the current Spanish incentive scheme for continuity of supply was analyzed under the perspective of the proposed approach.

Deconstructing Classical Water Models at Interfaces and in Bulk

Using concepts from perturbation and local molecular field theories of liquids we divide the potential of the SPC/E water model into short and long ranged parts. The short ranged parts define a minimal reference network model that captures very well the structure of the local hydrogen bond network in bulk water while ignoring effects of the remaining long ranged interactions. This deconstruction can provide insight into the different roles that the local hydrogen bond network, dispersion forces, and long ranged dipolar interactions play in determining a variety of properties of SPC/E and related classical models of water. Here we focus on the anomalous behavior of the internal pressure and the temperature dependence of the density of bulk water. We further utilize these short ranged models along with local molecular field theory to quantify the influence of these interactions on the structure of hydrophobic interfaces and the crossover from small to large scale hydration behavior. The implications of our findings for theories of hydrophobicity and possible refinements of classical water models are also discussed.

From Reference Network Model to Economic Ones: First Approach to Electrical Distribution Network Business Total Cost Function in Spain

Current EU legislation establishes that distribution and transmission systems shall be operated through legally separate entities where vertically integrated undertakings exist. At the same time, European Union’s Energy Policy promotes generation of electricity from renewable sources which mostly takes the form of Distributed Generation (DG from now on). In the context of a vertically integrated company the development of this business may be easier as its impact on the distribution network segment (connection costs) would be internalized. However, when infrastructure and generation business are separated these costs become externalities that tend to be borne by Distribution System Operators´ (DSO from now on).As a result DSOs usually ask for compensations motivated by connections of Distributed Generation to their networks, while Distributed Generators claim that their impact over network could be positive to the distribution activity. Both groups of interests, DSO’s and DG companies are pressing on regulators to guarantee that their positions materialize into each country’s energy regulation. Aside from this debate, National Regulatory Agencies should tackle this problem using all available information and technical tools to ensure that they take appropriate regulatory measures to fulfill with their functions. Moreover, this problem will also be affected by the type of regulatory pricing scheme that applies to distribution (there are two general ways to regulate remuneration of DSO´s activity: incentive regulation versus cost of service regulation). Thus the problem should be solved by taking into account both elements: robust estimation of the cost functions of both businesses (in order to properly consider the size of externalities) and the type of regulatory framework of the distribution activity (which usually represent an ex ante constraint for the regulator).This paper is a contribution along this line. It introduces a new estimation for the Network Business Total Cost function for the distribution activity in Spain. This will provide some hints and references about the case study and will allow proposing a new formula to evaluate economies of scale and the sensitivity of this function to the introduction of distributed generation