A Critical Review of Robustness in Power Grids using Complex Networks Concepts

Complex network theory for analyzing robustness in energy gridsThis paper reviews the most relevant works that have investigated robustness in power grids using Complex Networks (CN) concepts. In this broad field there are two different approaches. The first one is based solely on topological concepts, and uses metrics such as mean path length, clustering coefficient, efficiency and betweenness centrality, among many others. The second, hybrid approach consists of introducing (into the CN framework) some concepts from Electrical Engineering (EE) in the effort of enhancing the topological approach, and uses novel, more efficient electrical metrics such as electrical betweenness, net-ability, and others. There is however a controversy about whether these approaches are able to provide insights into all aspects of real power grids. The CN community argues that the topological approach does not aim to focus on the detailed operation, but to discover the unexpected emergence of collective behavior, while part of the EE community asserts that this leads to an excessive simplification. Beyond this open debate it seems to be no predominant structure (scale-free, small-world) in high-voltage transmission power grids, the vast majority of power grids studied so far. Most of them have in common that they are vulnerable to targeted attacks on the most connected nodes and robust to random failure. In this respect there are only a few works that propose strategies to improve robustness such as intentional islanding, restricted link addition, microgrids and smart grids, for which novel studies suggest that small-world networks seem to be the best topology.This work has been partially supported by the project TIN2014-54583-C2-2-R from the Spanish Ministerial Commission of Science and Technology (MICYT), by the project S2013/ICE-2933 from Comunidad de Madrid and by the project FUTURE GRIDS-2020 from the Basque Government

Fluid flow queue models for fixed-mobile network evaluation

A methodology for fast and accurate end-to-end KPI, like throughput and delay, estimation is proposed based on the service-centric traffic flow analysis and the fluid flow queuing model named CURSA-SQ. Mobile network features, like shared medium and mobility, are considered defining the models to be taken into account such as the propagation models and the fluid flow scheduling model. The developed methodology provides accurate computation of these KPIs, while performing orders of magnitude faster than discrete event simulators like ns-3. Finally, this methodology combined to its capacity for performance estimation in MPLS networks enables its application for near real-time converged fixed-mobile networks operation as it is proven in three use case scenarios

Epon Communication Network Topology Planning Based on Node Importance of Active Distribution Network

A large amount of DGs (distributed generations) and distributed resources accessing to distribution network is a characteristic of present distribution network. So the concept of the active distribution network is proposed, which is a new form of distribution network with flexible power network structure and active control and management with high permeability of DGs in the distribution network. According to the actual operation state of power system, active distribution network actively manages the massive distributed power supply and adaptively adjusts the network to satisfy the requirements of economy and security power supply. This thesis aims to propose a feasible optimization scheme for the communication network based on the evaluation results of all nodes’ importance in the distribution network. This solution not only meets the current technical requirements, but also considers the possible expansion of communication network in the future. Different from the most used dual link connection for all communication network nodes, this section of this thesis selects a certain portion of the important nodes in the power grid for optimization, and the remaining nodes connected to the communication network adopt a single link. The optimization result can provide a more scientific and reasonable solution for planner to build a communication network. The link entropy index is used to evaluate the edges’ significance on maintaining the global connectivity for the whole power and communication network

Epon Communication Network Topology Planning Based on Node Importance of Active Distribution Network

A large amount of DGs (distributed generations) and distributed resources accessing to distribution network is a characteristic of present distribution network. So the concept of the active distribution network is proposed, which is a new form of distribution network with flexible power network structure and active control and management with high permeability of DGs in the distribution network. According to the actual operation state of power system, active distribution network actively manages the massive distributed power supply and adaptively adjusts the network to satisfy the requirements of economy and security power supply. This thesis aims to propose a feasible optimization scheme for the communication network based on the evaluation results of all nodes’ importance in the distribution network. This solution not only meets the current technical requirements, but also considers the possible expansion of communication network in the future. Different from the most used dual link connection for all communication network nodes, this section of this thesis selects a certain portion of the important nodes in the power grid for optimization, and the remaining nodes connected to the communication network adopt a single link. The optimization result can provide a more scientific and reasonable solution for planner to build a communication network. The link entropy index is used to evaluate the edges’ significance on maintaining the global connectivity for the whole power and communication network

Power Grid Network Evolutions for Local Energy Trading

The shift towards an energy Grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the distribution infrastructure. Today it is a hierarchical one designed to deliver energy from large scale facilities to end-users. Tomorrow it will be a capillary infrastructure at the medium and Low Voltage levels that will support local energy trading among prosumers. In our previous work, we analyzed the Dutch Power Grid and made an initial analysis of the economic impact topological properties have on decentralized energy trading. In this paper, we go one step further and investigate how different networks topologies and growth models facilitate the emergence of a decentralized market. In particular, we show how the connectivity plays an important role in improving the properties of reliability and path-cost reduction. From the economic point of view, we estimate how the topological evolutions facilitate local electricity distribution, taking into account the main cost ingredient required for increasing network connectivity, i.e., the price of cabling