Josep M. Selga

Heterogeneous communication architecture for the smart grid

The smart grid concept provides a solution to the growing recognition that current utility grids need an ICT deployment infrastructure based upgrade to allow millions of potential market players to operate and to cope with distributed generation, wide-area situational awareness, demand response, electric storage, and efficient electric transportation. Smart grid deployment is mainly about defining the necessary standards for ICT solutions. The design of the communication network associated with the smart grid involves detailed analysis of its communication requirements, a proposal of the appropriate protocol architecture, the choice of the most suitable technologies for each case study, and a scheme for the resultant heterogeneous network management system. Given the smart grid use cases, this article is focused on proposing a heterogeneous communication paradigm for smart grids based on power line communications and wireless networks. The proposal is related to the framework of the ITU ubiquitous sensor network architecture using the ITU next-generation network model. This architecture allows for better management of the QoS in the smart grid and should facilitate interoperability with other technologies.

Survey and Performance Comparison of AMR Over PLC Standards

Automatic meter reading (AMR) is an application implemented by power utilities which is becoming increasingly important in the utilities sector. It could be included in the more general environment of demand side management, which satisfies the need for more improved communications. AMR offers a better financial return due to the inclusion of other applications. Although there are several international standards which address AMR, most deployments are currently using proprietary systems. This fact may reflect that current standards do not fully cover this area. Since the power network reaches all energy meters, a convenient way to deploy AMR is to use the power lines as a transmission medium. The present-day situation is that there is mounting pressure to deploy AMR systems in a bid to provide better management of the energy demand in a bid to reduce global warming and create a more sustainable electrical system in our environmentally conscious society. This paper is focused on analyzing different standards and specifications related to AMR over powerline communications (PLC). Furthermore, two of them are chosen, implemented, and simulated using the OPNET modeler. The main goal of the implemented applications is to obtain comparative results of the two most known standard applications in AMR over PLC.

Voice synchronization in packet switching networks

An algorithm for voice synchronization for packet switching networks is presented. The algorithm has been tested both in simulation and on a real network. The algorithm runs on the TRAME packet switching network for both the Vocoder and CELP DoD voice coding standards. Some results of these tests are presented. Some details of the algorithm development and implementation are given as well.<<ETX>>

Use case analysis of real-time low voltage network management

Real-time low voltage network management is becoming possible thanks to massive smart meter rollouts, integration of them to distribution network management systems and utilization of distributed energy resources in distribution network management. Nowadays low voltage network management is emerging by integrating automatic meter infrastructure to centralized systems like SCADA/DMS. European project INTEGRIS is proposing a distributed approach based on hybrid and meshed communication. The paper is focused on low voltage network management use cases developed within the context of INTEGRIS and their ICT requirements to test the level of performance provided by the ICT architecture developed in the mentioned project.

Next-generation QoS control architectures for distribution smart grid communication networks

This article presents a proposal for applying the ITU-T end-to-end QoS control architecture for next-generation networks to the distribution smart grid communication networks. We propose the use of a QoS broker device to enhance the QoS in the smart grid electrical distribution access domains by providing a centralization of QoS management. Our proposal takes decisions based on current network data traffic flows, existing QoS policies and customer service level agreements and facilitates interoperability with other technology domains in order to achieve seamless end-to-end QoS. The key feature of this end-toend QoS control is the mapping of QoS parameters mainly between broadband power line and wireless technologies that principally serve the distribution smart grid but it can be applied to other communication technologies as well.

Solutions to the Computer Networking Challenges of the Distribution Smart Grid

Communication networks play a crucial role in the context of Smart Grids since they enable a broad set of appealing facilities, from both producers and consumers side, to be effectively delivered. So far, several standards (e.g., IEC 61850-5) have been presented aiming to detail the specific requirements for such networks on the Smart Grid domain. However, the definitions proposed by these standards are confined to a reduced part of the grid: the primary substation. This situation prevents electrical distribution networks from fully exploiting the Smart Grid concept as a whole (i.e., provide truly distributed energy resources). The purpose of this paper is to (1) provide a further insight qualitative analysis of the yet-unexplored communication requirements raised by the electrical distribution Smart Grid, and (2) propose novel solutions targeted at creating link layer networks spanning a given electrical distribution area to allow faster and more reliable communication. Specifically, these solutions are devoted to extend all standards and communication mechanisms already defined for primary substations, to the whole grid by considering the electrical distribution grid as a collection of virtual substations. Furthermore, collected experiences throughout the implementation of this proposal envisage some alternatives to boost the performance of this protocol in terms of reliability and latency.

A Genetic QoS-Aware Routing Protocol for the Smart Electricity Networks

This paper presents a QoS-aware routing protocol suitable for distribution of smart electricity grids based on heterogeneous machine to machine communications. The distribution Smart Grid needs high performance communication networks capable of handling QoS, an issue that is addressed by the present paper. The proposed algorithm is a merger between a genetic algorithm (GA) and Ticket-Based Routing (TBR), which is an on-demand routing protocol for ad hoc networks that provide quality of service. A suitable parameterization of the GA parameters is needed in order to use this protocol in the coming Smart Grid networks. The resulting routing protocol, named genetic algorithm with TBR algorithm for Smart Grids (GATAS), is an adapted intelligent evolution of the TBR. The performance of TBR has been improved by reducing the overhead of routing packets in the network and by minimizing the communication latency due to its on-demand behavior. Experimental evidence indicates that the likelihood of finding the optimum route using multiobjective dynamic metrics increases when the genetic algorithm is applied. In this paper, the main simulation results on the parameterization carried out are discussed, and the proposed attributes of the GA are described.

Simulation and modeling of the coexistence of polling and contention in PLC based AMR systems

MAC protocols for PLC networks must overcome difficulties stronger than those found in other systems such as the need to cope with several hops and with very noisy environments. Polling protocols are widely used in PLC based AMR (automatic meter reading) systems but they present several drawbacks, as their inherent impossibility to automatically associate new meters to the system. Contention protocols over PLC do allow for automatic association of new meters but they suffer from low efficiency basically due to the multihop nature of PLC based AMR systems. A combination of both types of protocols seems a wise option. One possibility is to partition the time into two periods, one for polling and another one for contention, but it requires resource consuming network-wide synchronization in a system that must be especially inexpensive. Another possibility is to superimpose both types of communication in a proper manner. The choice has advantages and disadvantages and affects also the topology control function. A simulation model of the PLC system has been carried out based on OPNET Modeler. The paper presents this model and results that basically compare the two aforementioned alternatives of protocol combination. An analytical model developed by the authors in a previous work is used to complement the simulation, allowing for the assessment of the system behavior in a stable topology situation.

Smart Grid ICT Research Lines out of the European Project INTEGRIS

The Smart Grid is at the same time a part of the Internet of Things and an example of a cyber-physical system where the physical power grid is surrounded by many intelligent and communication devices that allow for an enhanced management of the power network itself. The Smart Grid may bring great performance benefits to the society in terms of enabling the massive introduction of renewable energy sources in the power grid, the reduction of carbon emissions and improved sustainability among others. However, it may also bring big computer networking challenges to achieve the needed high reliability and low latency and even risks in terms of cybersecurity since it opens the power system to at least the same threats faced by the Internet. In fact, it is reasonable to think that the vulnerabilities will be still larger, considering the novel, heterogeneous and distributed nature of the Smart Grid. Furthermore, cybersecurity in Smart Grids is essential for the survival and feasibility of this electricity concept, thus making the risks still more relevant. Such ICT systems and computer networks supporting the Smart Grid concept need to be very efficient and to comply with very stringent requirements, at least for some of the services to be provided. They also need to efficiently integrate and manage in a single network a vast array of technologies among which diverse link layer technologies, meshed and non-meshed Ethernet networks, different cybersecurity protocols, networking at different layers, cognitive systems and storage and replication of data. The objective is to provide a system capable of providing adequate service to the wide array of applications foreseen for the Smart Grid but the complexity of the problem is really impressive and it is not possible to focus all of its aspects in a single paper or even project. The present paper presents these requirements, the solutions and results developed and tested in the FP7 European Project INTEGRIS as well as the future challenges and research lines identified as a result of the project and some prospective solutions.

Performance of a Policy-Based Management System in IPv6 Networks Using COPS-PR

To guarantee the correct QoS, the new generation core networks are best managed by the use of a centralized server. Most of these networks use DiffServ due to its scalability, an important feature for large networks. A Bandwidth Broker architecture is a policy-based management system which purpose is to manage DiffServ networks in a centralized manner performing admission control and policy deliveries to network nodes. This paper presents the implementation of a bandwidth broker architecture for the management of QoS in DiffServ dual networks (IPv4/IPv6). This implementation, which has been programmed in JAVA, uses COPS-PR as an intra-domain communication protocol and manages the policies based on SLA/SLS preconfigured by the administrator. The performance of the proposed architecture has been tested by implementing a real IPv6 DiffServ domain testbed controlled by the developed Bandwidth Broker. The results of these tests and the corresponding conclusions are also presented.