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- B. Yang, K. V. Katsaros, W. K. Chai, G. Pavlou, Cost-efficient Low Latency Communication Infrastructure for Synchrophasor Applications in Smart Grids, IEEE Systems Journal, 2016
With the introduction of distributed renewable energy resources and new loads, such as electric vehicles, the power grid is evolving to become a highly dynamic system that necessitates continuous and fine-grained observability of its operating conditions. In the context of the medium voltage (MV) grid, this has motivated the deployment of phasor measurement units (PMUs), that offer high-precision synchronized grid monitoring, enabling mission-critical applications such as fault detection/location. However, PMU-based applications present stringent delay requirements, raising a significant challenge to the communication infrastructure. In contrast to the high voltage domain, there is no clear vision for the communication and network topologies for the MV grid; a full-fledged optical fiber-based communication infrastructure is a costly approach due to the density of PMUs required. In this study, we focus on the support of low-latency PMU-based applications in the MV domain, identifying and addressing the tradeoff between communication infrastructure deployment costs and the corresponding performance. We study a large set of real MV grid topologies to get an in-depth understanding of the various key latency factors. Building on the gained insights, we propose three algorithms for the careful placement of high capacity links, targeting a balance between deployment costs and achieved latencies. Extensive simulations demonstrate that the proposed algorithms result in low-latency network topologies while reducing deployment costs by up to 80% in comparison to a ubiquitous deployment of costly high capacity links.
- M. Pignati, L. Zanni, P. Romano and M. Paolone, Fault Detection and Faulted Line Identification in Active Distribution Networks using Synchrophasors-based Real-Time State Estimation, IEEE Transactions on Power Delivery, 2016
- Styliani Sarri, Lorenzo Zanni, Miroslav Popovic, Jean-Yves Le Boudec, Mario Paolone, Performance Assessment of Linear State Estimators Using Synchrophasor Measurements, IEEE Transactions on Instrumentation and Measurement, 2016
This paper aims to assess the performance of linear state estimation (SE) processes of power systems relying on synchrophasor measurements. The performance assessment is conducted with respect to two different families of SE algorithms, i.e., static ones represented by weighted least squares (WLS) and recursive ones represented by Kalman filter (KF). To this end, this paper firstly recalls the analytical formulation of linearWLS state estimator (LWLS-SE) and Discrete KF state estimator (DKF-SE). We formally quantify the differences in the performance of the two algorithms. The validation of this result, together with the comprehensive performance evaluation of the considered state estimators, is carried out using two case studies, representing distribution (IEEE 123-bus test feeder) and transmission (IEEE 39-bus test system) networks. As a further contribution, this paper validates the correctness of the most common process model adopted in DKF-SE of power systems.
- Yue Cao, Ning Wang, George Kamel, and Young-Jin Kim, An Electric Vehicle Charging Management Scheme Based on Publish/Subscribe Communication Framework, IEEE Systems Journal, 2015
Motivated by alleviating CO2 pollution, Electric Vehicle (EV) based applications have recently received wide interests from both commercial and research communities by using electric energy instead of traditional fuel energy. Although EVs are inherently with limited travelling distance, such limitation could be overcome by deploying public Charging Stations (CSs) to recharge EVs battery during their journeys. In this article, we propose a communication framework for on-the-move EV charging scenario, based on Publish/Subscribe (P/S) mechanism to disseminate necessary information about CSs to EVs. Concerning privacy issue, those EVs subscribing to such information could then locally make their individual decisions to select desired CSs for charging, rather than applying a centralized manner where private EV information is required to be released through communication. A core part of our communication framework is the utilization of Road Side Units (RSUs) to bridge the information flow from CSs to EVs, which has been regarded as a type of cost-efficient communication infrastructure. Under this design, we introduce two complementary communication modes, namely Push and Pull Modes, in order to enable the required information dissemination operation. Both analysis and simulation show the advantage of Pull Mode, in which the information is cached at RSUs to support asynchronous communication. We further propose a remote reservation service based on the Pull Mode, such that the CS-selection decision making can utilize the knowledge of EVs’ charging reservation, as published from EVs through RSUs to CSs. Results show that both the performance at CS and EV sides are further improved based on using this anticipated information.
- W. K. Chai, N. Wang, K. V. Katsaros, G. Kamel, G. Pavlou, S. Melis, M. Hoefling, B. Vieira, P. Romano, S. Sarri, T. Tesfay, B. Yang, F. Heimgaertner, M. Pignati, M. Paolone, M. Menth, E. Poll, M. Mampaey, H. Bontius and C. Develder, An Information-centric Communication Infrastructure for Real-time State Estimation of Active Distribution Networks, IEEE Transactions on Smart Grid, 2015
The evolution towards emerging Active Distribution Networks (ADNs) can be realized via a Real-Time State Estimation (RTSE) application facilitated by the use of Phasor Measurement Units (PMUs). A critical challenge in deploying PMU-based RTSE applications at large scale is the lack of a scalable and flexible communication infrastructure for the timely (i.e., sub-second) delivery of the high volume of synchronized and continuous synchrophasor measurements. We address this challenge by introducing a communication platform called C-DAX based on the information-centric networking (ICN) concept. With a topic-based publish-subscribe engine that decouples data producers and consumers in time and space, C-DAX enables efficient synchrophasor measurement delivery as well as flexible and scalable (re)configuration of PMU data communication for seamless full observability of power conditions in complex and dynamic scenarios. Based on the derived set of requirements for supporting PMU-based RTSE in ADNs, we design the ICN-based C-DAX communication platform, together with a joint optimized physical network resource provisioning strategy in order to enable the agile PMU data communications in near real-time. In this work, C-DAX is validated via a field trial implementation deployed over a sample feeder in a real distribution network; it is also evaluated through simulation-based experiments using a large set of real medium voltage grid topologies currently operating live in the Netherlands. This is the first work that applies emerging communication paradigms, such as ICN, to smart grids while maintaining the required hard real-time data delivery as demonstrated through field trials at national scale. As such, it aims to become a blueprint for the application of ICN-based general purpose communication platforms to ADNs.
- Konstantinos V. Katsaros, W.K. Chai, N. Wang, G. Pavlou, H. Bontius and M. Paolone, Information-Centric Networking for Machine-to-Machine Data Delivery – A Case Study in Smart Grid Applications, IEEE Network, Special Issue on Information-Centric Networking Beyond Baseline Scenarios: Research Advances and Implementation, Vol.28, no.3, 2014
Largely motivated by the proliferation of content-centric applications in the Internet, information-centric networking has attracted the attention of the research community. By tailoring network operations around named information objects instead of end hosts, ICN yields a series of desirable features such as the spatiotemporal decoupling of communicating entities and the support of in-network caching. In this article, we advocate the introduction of such ICN features in a new, rapidly trans- forming communication domain: the smart grid. With the rapid introduction of multiple new actors, such as distributed (renewable) energy resources and electric vehicles, smart grids present a new networking landscape where a diverse set of multi-party machine-to-machine applications are required to enhance the observability of the power grid, often in real time and on top of a diverse set of communication infrastructures. Presenting a generic architectural framework, we show how ICN can address the emerging smart grid communication challenges. Based on real power grid topologies from a power distribution network in the Netherlands, we further employ simulations to both demonstrate the feasibility of an ICN solution for the support of real-time smart grid applications and further quantify the perfor- mance benefits brought by ICN against the current host-centric paradigm. Specifically, we show how ICN can support real-time state estimation in the medium voltage power grid, where high volumes of synchrophasor measurement data from distributed vantage points must be delivered within a very stringent end-to-end delay constraint, while swiftly overcoming potential power grid component failures.
- Paolo Romano, Mario Paolone, Enhanced Interpolated-DFT for Synchrophasor Estimation in FPGAs: Theory, Implementation, and Validation of a PMU Prototype, IEEE Transactions on Instrumentation and Measurement, 2014
The literature on the subject of synchrophasor estimation (SE) algorithms has discussed the use of interpolated discrete Fourier transform (IpDFT) as an approach capable to find an optimal tradeoff between SE accuracy, response time, and computational complexity. Within this category of algorithms, this paper proposes three contributions: 1) the formulation of an enhanced-IpDFT (e-IpDFT) algorithm that iteratively compensates the effects of the spectral interference produced by the negative image of the main spectrum tone; 2) the assessment of the influence of the e-IpDFT parameters on the SE accuracy; and 3) the discussion of the deployment of IpDFT-based SE algorithms into field programmable gate arrays, with particular reference to the compensation of the error introduced by the free-running clock of A/D converters with respect to the global positioning system (GPS) time reference. The paper finally presents the experimental validation of the proposed approach where the e-IpDFT performances are compared with those of a classical IpDFT approach and to the accuracy requirements of both P and M-class phasor measurement units defined in the IEEE Std. C37.118-2011.
- Kevin Mets, Juan Aparicio Ojea, Chris Develder, Combining Power and Communication Network Simulation for Cost-Effective Smart-Grid Analysis, IEEE Communications Surveys and Tutorials, special issue on Energy and Smart Grid, 2014, pp. 1-26
Todays electricity grid is transitioning to a so-called smart grid. The associated challenges and funding initiatives have spurred great efforts from the research community to propose innovative smart grid solutions. To assess the performance of possible solutions, simulation tools offer a cost effective and safe approach. In this paper we will provide a comprehensive overview of various tools and their characteristics, applicable in smart grid research: we will cover both the communication and associated ICT infrastructure, on top of the power grid. First, we discuss the motivation for the development of smart grid simulators, as well as their associated research questions and design challenges. Next, we discuss three types of simulators in the smart grid area: power system simulators, communication network simulators, and combined power and communication simulators. To summarize the findings from this survey, we classify the different simulators according to targeted use cases, simulation model level of detail, and architecture. To conclude, we discuss the use of standards and multi-agent based modeling in smart grid simulation.
- Wei Koong Chai, Vaios Kyritsis, Konstantinos V. Katsaros, George Pavlou, Resilience of Interdependent Communication and Power Distribution Networks against Cascading Failures, in Proceedings of IFIP Networking 2016, 17-19 May 2016, Vienna, Austria.
The operations of many modern cyber-physical systems, such as smart grids, are based on increasingly interdependent networks. The impact of cascading failures on such networks has recently received significant attention due to the corresponding effect of these failures on the society. In this paper, we conduct an empirical study on the robustness of interdependent systems formed by the coupling of power grids and communication networks by putting real distribution power grids to the test. We focus on the assessment of the robustness of a large set of medium-voltage (MV) distribution grids, currently operating live in the Netherlands, against cascading failures initiated by different types of faults / attacks. We consider both unintentional random failures and malicious targeted attacks which gradually degrade the capability of the entire system and we evaluate their respective consequences. Our study shows that current MV grids are highly vulnerable to such cascades of failures. Furthermore, we discover that a small-world communication network structure lends itself to the robustness of the interdependent system. Also interestingly enough, we discover that the formation of hub hierarchies, which is known to enhance independent network robustness, actually has detrimental effects against cascading failures. Based on real MV grid topologies, our study yields realistic insights which can be employed as a set of practical guidelines for distribution system operators (DSOs) to design effective grid protection schemes.
- Michael Hoefling, Florian Heimgaertner, and Michael Menth, Advanced Communication Modes for the Publish/Subscribe C-DAX Middleware, accepted for the IFIP/IEEE International Workshop on the Management of Fog Computing and the Internet of Things (ManFIoT) collocated with the IEEE/IFIP Network Operations and Management Symposium (NOMS), 29 April 2016.
C-DAX is a cyber-secure publish/subscribe middleware tailored to the needs of smart grids, offering end-to-end security, and scalable and resilient communication among participants in a smart grid. While C-DAX’ broker-based publish/ subscribe mechanisms are well-suited for scalable information dissemination with regard to high numbers of publishers and subscribers, (1) additional transmission delays are inherent to the design because of multi-hop application layer forwarding, and (2) interactive (probably legacy) applications are prohibited due to the one-way publish/subscribe paradigm and potential dependencies on IP communication. This work presents two advanced communication modes for the C-DAX architecture, addressing those issues: (1) broker-less publish/subscribe for delay-sensitive applications, and (2) transparent IP-tunneling over publish/subscribe for legacy applications. Those modes further improve C-DAX’ suitability for smart grid applications, including enhanced real-time application support, and transparent support for legacy smart grid communication protocols.
- Yue Cao, Ning Wang, Young Jin Kim, and Change Ge, A Reservation Based Charging Management for On-the-move EV Under Mobility Uncertainty, in Proceedings of the IEEE Online Conference on Green Communications, 10-12 November 2015.
With the continually increased attention on Electric Vehicles (EVs) due to environment impact, public Charging Stations (CSs) for EVs will become common. However, due to the limited electricity of battery, the driver may experience discomfort for long charging waiting time, if travelling towards a CS which is heavily loaded for charging. With this concern, we manage on-the-move EV charging by coordinating which CS to select for charging, and propose a CS-selection scheme considering EVs anticipated charging reservations generally including arrival time and expected charging time, in particular the parking duration is further considered in this paper. Upon this, by addressing mobility uncertainty that EVs may not reach their selected CSs on time due to uncertain traffic condition on the road, a periodical reservation updating for requesting the change of CS-selection decision is proposed to further coordinate charging management. The motivation for this is mainly due to that the mobility uncertainty affects the accuracy of reported reservation information, concerning the arrival time at selected CSs and expected charging time upon arrival. Evaluation results show the effectiveness of our proposal when considering realistic EV and CS characteristics.
- Michael Hoefling, Florian Heimgaertner, Daniel Fuchs and Michael Menth, jOSEF: A Java-Based Open-Source Smart Meter Gateway Experimentation Framework, in Proceedings of the D-A-CH Conference on Energy Informatics (Energieinformatik 2015), November 2015, Karlsruhe, Germany
Smart meter gateways are the core component of the advanced metering infrastructure in Germany, and provide a unied interface for metering data retrieval to third parties. Different standards and communication protocols exist for smart metering, ranging from transmission protocols to architectural recommendations. This work briefly presents the concept of the German BSI TR-03109 smart metering architecture, reviews implementations of smart metering protocols and architectures, and provides a Java-based open-source smart meter gateway experimentation framework (jOSEF). The proposed framework combines and extends established protocol frameworks to provide a flexible tool for the validation of smart metering communication use cases involving smart meter gateways.
- W.K. Chai, K.V. Katsaros, M. Strobbe, P. Romano, C. Ge, C. Develder, G. Pavlou and N. Wang, Enabling Smart Grid Applications with ICN, in Proceedings of the 2nd ACM Conference on Information-Centric Networking (ICN 2015), 30 September - 2 October 2015, San Francisco, California, USA.
We have harnessed the salient features of information-centric networking (ICN) and implemented a communication infrastructure, called C-DAX, for supporting smart grid applications. We will demonstrate the operations of C-DAX both in a laboratory setup and a real field trial that involves the deployment of C-DAX in a live electricity grid in the Netherlands. This demo will showcase the capabilities of C-DAX, highlighting how ICN satisfies stringent smart grid application requirements.
- Fabian van den Broek, Erik Poll, and Barbara Vieira, Securing the information infrastructure for EV charging, in Proceedings of the International Workshop on Communication Applications in Smart Grid (CAGS 2015) collocated with the 7th EAI International Conference on Wireless and Satellite Systems (WISATS 2015), July 2015, Bradford, UK
We consider the functional and security requirements for the information exchanges in the infrastructure for EV charging being trialled in the Netherlands, which includes support for congestion management using the smart charging protocol OSCP. We note that current solutions do not provide true end-to-end security, even if all communication links are secured (for instance with TLS), as some data is forwarded between multiple parties. We argue that securing the data itself rather than just securing the communication links is the best way to address security needs and provide end-to-end security. Moreover, because of the number of parties involved and the fact that the precise roles of these parties are still evolving, we argue that more data-centric communication solutions, using pub/sub (publish/subscribe) middleware, may be better suited than using point-to-point communication links between all parties, given the exibility and scalability provided by pub/sub middleware.
- Styliani Sarri, Marco Pignati, Paolo Romano, Lorenzo Zanni and Mario Paolone, A Hardware-in-the-Loop Test Platform for the Performance Assessment of a PMU-based Real-Time State Estimator for Active Distribution Networks, in Proceedings of PowerTech 2015, 29 June - 2 July 2015, Eindhoven, The Netherlands
The paper describes the development of a Hardware-in-the-Loop (HIL) test platform for the performance assessment of a PMU-based sub-second linear Real-Time State Estimator (RTSE) for Active Distribution Networks (ADNs). The estimator relies on the availability of data coming from Phasor Measurement Units (PMUs) and can be applied to both balanced and unbalanced ADNs. The paper first illustrates the architecture of the experimental HIL setup that has been fully designed by the Authors. It consists of a Real-Time Simulator (RTS) that models the electrical network model as well as the measurement infrastructure composed by virtual PMUs. These virtual devices stream their data to a real Phasor Data Concentrator (PDC) suitably coupled with a Discrete Kalman Filter State Estimator (DKF-SE). By using this experimental setup, the paper discusses the performance assessment of the whole process in terms of estimation accuracy and time latencies. In the RTS, a real ADN located in the Netherlands has been modeled together with the associated PMUs.
- Florian Heimgaertner, Michael Hoefling, Barbara Vieira, Erik Poll, and Michael Menth, A Security Architecture for the Publish/Subscribe C-DAX Middleware, in Proceedings of the IEEE International Workshop on Security and Privacy for Internet of Things and Cyber-Physical Systems (IoT/CPS-Security 2015) collocated with the IEEE International Conference on Communications (ICC 2015), June 2015, London, UK
The limited scalability, reliability, and security of today's utility communication infrastructures are main obstacles for the deployment of smart grid applications. The C-DAX project aims at providing a cyber-secure publish/subscribe middleware tailored to the needs of smart grids. C-DAX provides end-to-end security, and scalable and resilient communication among participants in a smart grid. This work presents the C-DAX security architecture, and proposes different key distribution mechanisms. Security properties are defined for control plane and data plane communication, and their underlying mechanisms are explained. The presented work is partially implemented in the C-DAX prototype and will be deployed in a field trial.
- Michael Hoefling, Florian Heimgaertner, Daniel Fuchs, Michael Menth, Paolo Romano, Teklemariam Tesfay, Mario Paolone, Jimmie Adolph, and Vidar Gronas, Integration of IEEE C37.118 and Publish/Subscribe Communication, in Proceedings of the IEEE International Conference on Communications (ICC 2015), June 2015, London, UK
IEEE C37.118 is the current standard for synchrophasor measurements in power systems. It defines the measurement method and communication protocols for the entities in a synchrophasor network. The standard offers two different modes for client-server communication, but cannot be used unchanged over publish/subscribe communication architectures, whose major advantage is simplified and incremental integration of new applications. This work reviews the communication part of IEEE C37.118, and provides an adapter-based solution to easily connect and integrate entities in a synchrophasor network over a publish/subscribe communication architecture. The proposed adapters offer standard-compliant communication between the synchrophasor measurement network entities to facilitate the exchange of measurement data.
- Michael Hoefling, Florian Heimgaertner, Michael Menth, and Herman Bontius, Traffic Estimation of the PowerMatcher Application for Demand Supply Matching in Smart Grids, in Proceedings of the ITG/GI Workshop on Middleware for a Smarter Use of Electric Energy (MidSEE) colocated with the ITG/GI International Conference on Networked Systems (NetSys 2015), March 2015, Cottbus, Germany.
The electrical grid is changing from a centralized system with predictable and controllable power generation to a system integrating large numbers of distributed energy resources including weather-dependent renewables. As a consequence, the future retail energy market for electrical energy will have many more participants and see more volatile prices than today, creating the need for new communication and trading infrastructures facilitating. In this paper, we briefly review PowerMatcher as a possible approach for such an infrastructure, and analytically evaluate its communication characteristics. PowerMatcher is a multi-agent based smart grid communication framework developed by TNO which enables market integration of distributed energy resources and automatic demand supply matching. While the trading side of the framework is well understood, there is no study that considers the communication side. Our results show that PowerMatcher enables scalable retail energy transactions with millions of participants requiring only moderate resources on the communication's side.
- Michael Hoefling, Florian Heimgaertner, Michael Menth, Konstantinos V. Katsaros, Paolo Romano, Lorenzo Zanni, and George Kamel, Enabling Resilient Smart Grid Communication over the Information-Centric C-DAX Middleware, in Proceedings of the ITG/GI International Conference on Networked Systems (NetSys 2015), March 2015, Cottbus, Germany.
Limited scalability, reliability, and security of todays utility communication infrastructures are main obstacles to the deployment of smart grid applications. The C-DAX project aims at providing and investigating a communication middleware for smart grids to address these problems, applying the information-centric networking and publish/subscribe paradigm. We briefly describe the C-DAX architecture, and extend it with a flexible resilience concept, based on resilient data forwarding and data redundancy. Different levels of resilience support are defined, and their underlying mechanisms are described. Experiments show fast and reliable performance of the resilience mechanism.
- Yue Cao, Ning Wang and George Kamel, A Publish/Subscribe Communication Framework for Managing Electric Vehicle Charging, in Proc. of the Third International Conference on Connected Vehicles and Expo (ICCVE 2014), Vienna, Austria, November 3-7, 2014.
Electric Vehicle (EV) based applications have recently received wide interests from both commercial and research communities, thanks to the avoidance of CO2 pollution by using electric energy instead of traditional fuel energy. With the deployment of public Charging Stations (CSs), the travelling distance of EVs could be substantially increased by recharging their electric energy during journeys. Different from the existing research on decision making to improve charging performance, in this paper we focus on how necessary dynamic information in relation to the charging service can be efficiently disseminated to on-the-move EVs which potentially require charging at CSs. We propose an efficient communication framework based on Publish/Subscribe (P/S) mechanism to disseminate necessary information of CSs to EVs. Those EVs subscribing to such information could then make their individual decisions to select a desired CS for charging, according to received information such as expected waiting time. A core part of communication framework is the utilization of Road Side Units (RSUs) to bridge the information flow from CSs to EVs, which has been regarded as a type of cost-efficient communication infrastructure. In this context, we introduce two complementary communication modes, namely Push and Pull Modes, in order to enable the required information dissemination operation. Both options are evaluated based on realistic simulation models, in particular on how information freshness can influence the overall charging performance based on a common CS selection strategy.
- Konstantinos V. Katsaros, Binxu Yang, Wei Koong Chai and George Pavlou, Low Latency Communication Infrastructure for Synchrophasor Applications in Distribution Networks, in Proc. of the IEEE 5th International Conference on Smart Grid Communications (SmartGridComm), Venice, Italy, November 3-6, 2014.
With the introduction of new power sources, such as distributed renewable energy resources, and loads, such as electric vehicles, electrical distribution networks must accommodate new energy flow patterns in a considerably dynamic environment. This leads to the need for increasing the observability of the grid to enable a series of mission-critical applications such as voltage/congestion control and fault detection/location. The deployment of Phasor Measurement Units appears to be a promising approach, offering high precision grid monitoring. However, while the low delay requirements of such applications raise a significant challenge to the communication infrastructure, there is currently no clear vision on the exact communication technologies and network topologies that could support these requirements. In this paper, we address this challenge by taking a systematic approach on the design of low latency communication infrastructures. Based on a large set of real medium voltage grid topologies from a European distribution network, we first perform a detailed analysis of the communication requirements. Guided by this analysis, we then propose two algorithms, PLeC and BW-PLeC algorithms, for the design of low latency communication infrastructures that enhance the currently available power-line communication technology with newer high-speed communication links at strategic points in the grid to satisfy the delay requirements while reducing deployment costs.
- Paolo Romano and Mario Paolone An Enhanced Interpolated-Modulated Sliding DFT for High Reporting Rate PMUs, in Proc. of the IEEE Workshop on Applied Measurements for Power Systems, Aachen, Germany, September 24-26, 2014.
The field of application of Phasor Measurement Units (PMUs) might be limited by the PMU measurements reporting latencies and achievable reporting rates, particularly with respect to power system protection applications that typically require very low latencies. A way to speed-up synchrophasor estimation algorithms based on the use of the Discrete Fourier Transform (DFT) refers to the usage of stable and accurate recursive processes for the DFT estimation. In this respect, this paper presents a synchrophasor estimation algorithm, called Interpolated-Modulated Sliding DFT (IpMSDFT), characterized by high accuracies and reduced latencies, enabling reporting rates up to thousands of synchrophasor per second. It is composed by two stages: (i) a guaranteed-stable technique for sample-by-sample DFT computation; (ii) an enhanced version of the classical IpDFT algorithm for synchrophasor estimation. The algorithm is analytically formulated and its digital design tailored to allow a feasible deployment on an FPGA-based PMU. The IpMSDFT-based PMU is finally validated with respect to the numerical stability of the proposed solution, its reporting latencies and the achievable reporting rates.
- Konstantinos V. Katsaros, Wei Koong Chai, Barbara Vieira and George Pavlou, Supporting Smart Electric Vehicle Charging with Information-Centric Networking, in proc. of the International Workshop on Quality, Reliability, and Security in Information-Centric Networking (Q-ICN), co-located with the 10th International Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness, Rhodes, Greece, August 20, 2014
Inspired by the proliferation of content-centric applications in the Internet, Information-Centric Networking (ICN) has emerged as a promising networking paradigm. Focusing on the delivery of content instead of the pairwise communication between end-hosts, ICN inherently supports location-independent content/information distribution, through the means of in-network caching and multicast; as well as mobile computing. However, so far the vast majority of ICN research efforts have mostly focused on the design of sound and scalable architectures and protocols for the current Internet application landscape. In this paper, we revisit ICN in the context of a radically different application environment of smart grids and in particular, the case of smart charging of electric vehicles. Based on a thorough description of the currently forming application environment in the Netherlands, we highlight the inefficiencies resulting from a host-centric model. We then show how ICN can address these limitations and ultimately support quality and security in such application environment. Besides qualitative benefits, our preliminary analysis also demonstrates that ICN can substantially reduce communication and security complexity, thus fostering the development and widespread adoption of the smart charging application.
- M. Pignati, L. Zanni, S. Sarri, R. Cherkaoui, J-Y. Le Boudec and M. Paolone, A Pre-Estimation Filtering Process of Bad Data for Linear Power Systems State Estimators using PMUs, in Proc. 18th International Conference on Power Systems Computation, Wroclaw, Poland, August 18-22, 2014.
The paper proposes a specific algorithm for the pre-estimation filtering of bad data (BD) in PMU-based power systems linear State Estimators (SEs). The approach is framed in the context of the so-called real-time SEs that take advantage of the high measurement frame rate made available by PMUs (i.e., 50 – 60 frames per second). In particular, the proposed algorithm examines PMU measurement innovations for each new received set of data in order to locate anomalies and apply countermeasures. The detection and identification scheme is based on: (i) the forecasted state of the network obtained by means of a linear Kalman filter, (ii) the current network topology, (iii) the accuracy of the measurement devices and (iv) their location. The incoming measurement from each PMU is considered reliable, or not, according to a dynamic threshold defined as a function of the confidence of the predicted state estimated by using an AutoRegressive Integrated Moving Average (ARIMA) process. The performances of the proposed algorithm are validated with respect to single and multiple bad data of different nature and magnitudes. Furthermore, the algorithm is also tested against faults occurring in the power system to show its robustness during these unexpected operating conditions.
- L. Zanni, S. Sarri, M. Pignati, R. Cherkaoui and M. Paolone, Probabilistic Assessment of the Process-Noise Covariance Matrix of Discrete Kalman Filter State Estimation of Active Distribution Networks, in Proc. 13th International Conference on Probabilistic Methods Applied to Power Systems, Durham, July 7-10, 2014.
The accuracy of state estimators using the Kalman Filter (KF) is largely influenced by the measurement and the process noise covariance matrices. The former can be directly inferred from the available measurement devices whilst the latter needs to be assessed, as a function of the process model, in order to maximize the KF performances. In this paper we present different approaches that allow assessing the optimal values of the elements composing the process noise covariance matrix within the context of the State Estimation (SE) of Active Distribution Networks (ADNs). In particular, the paper considers a linear SE process based on the availability of synchrophasors measurements. The assessment of the process noise covariance matrix, related to a process model represented by the ARIMA [0,1,0] one, is based either on the knowledge of the probabilistic behavior of nodal network injections/absorptions or on the aposteriori knowledge of the estimated states and their accuracies. Numerical simulations demonstrating the improvements of the KF-SE accuracy achieved by using the calculated matrix Q are included in the paper. A comparison with the Weighted Least Squares (WLS) method is also given for validation purposes.
- Michael Hoefling, Cynthia G. Mills, Michael Menth, Distributed Load Balancing for Resilient Information-Centric SeDAX Networks, in Proc. IEEE/IFIP Network Operations and Management Symposium (NOMS 2014), Krakow, Poland, May 5-9, 2014.
SeDAX is a publish/subscribe based information centric networking architecture where publishers send messages to the appropriate message broker (SeDAX node) over a Delauny triangulated overlay of SeDAX nodes. SeDAX nodes and topics are associated with geo-coordinates. A topic is stored on the primary and secondary SeDAX nodes, respectively closest and second-closest to the topic’s coordinate. SeDAX is resilient because the overlay automatically reroutes messages of a topic to its secondary SeDAX should its primary SeDAX node fail. The current SeDAX version determines the coordinate of a topic by hashing its name. This kind of topic allocation is static, which is problematic in case of load imbalance.
In this work, we propose a topic delegation mechanism for SeDAX to make the assignment of topics to nodes dynamic. We define the load of SeDAX nodes and coordinates for different levels of resilience and propose distributed algorithms for load balancing. Simulations show that significant load imbalance can occur with static topic assignment and that the proposed algorithms achieve very good load balancing results.
- Michael Hoefling, Florian Heimgaertner, Benjamin Litfinski, Michael Menth, A Perspective on the Future Retail Energy Market, in Proc. Workshop on Demand Modeling and Quantitative Analysis of Future Generation Energy Networks and Energy Efficient Systems (FGENET) collocated with 17th International GI/ITG Conference on "Measurement, Modelling and Evaluation of Computing Systems" and "Dependability and Fault-Tolerance" (MMB & DFT 2014), Bamberg, Germany, March 17-19, 2014.
Electrical energy will be more expensive and less predictable in the near future. A leading factor in this trend is the mass deployment of renewable energy sources. In this paper, we sketch the structure of the electrical energy grid and explain why power supply will be more demanding in the future. More volatile energy prices and small energy suppliers will create more activity on the retail energy market (REM). We present a perspective on the future REM that calls for communication support to satisfy the information needs of the market participants.
- Barbara Vieira, Erik Poll, A Security Protocol for Information-Centric Networking in Smart Grids, in Proc. SEGS 2013: Smart Energy Grid Security Workshop, Berlin, Germany, November 8, 2013.
The C-DAX project aims at providing a secure overlay network, as an overlay over an IP network, that provides an information-centric network (ICN) tailored to the needs and the capabilities of smart grids. This paper addresses how end-to-end security can be enforced in information-centric networks by proposing a protocol based on the concept of identity-based encryption, a type of public-key cryptography.
- Michael Hoefling, Cynthia G. Mills, Michael Menth, Analyzing Storage Requirements of the Resilient Information-Centric SeDAX Architecture, in Proc. IEEE 4th International Conference on Smart Grid Communications (SmartGridComm), Vancouver, Canada, October 21-24, 2013.
We develop and analyze algorithms that reduce the storage capacity required by SeDAX (Secure Data-centric Application eXtensible) in the presence of simultaneous node failures. The SeDAX infrastructure for smart grids uses data redundancy for a high level of reliability. It is an information-centric approach using resilient data forwarding in a Delaunay triangulated overlay. While SeDAX’s data forwarding scheme is well understood, there is no study that considers the SeDAX storage capacity necessary to survive multiple node failures. Our results are compared with the theoretical lower bound of SeDAX and the lower bound of an idealized storage system. The presented algorithms can be used to reduce storage requirements of SeDAX in practice.
- M. Paolone, M, Pignati, P. Romano, S. Sarri, L. Zanni, R. Cherkaoui, A Hardware-in-the-Loop Test Platform for the Real-Time State Estimation of Active Distribution Networks using Phasor Measurement Units, in Proc. Cigré Colloquium, Yokohama, Japan, October 6-9, 2013.
The paper describes the development and the performance assessment of a Hardware-in-the-Loop (HIL) test platform built as a proof-of-concept of a sub-second State Estimator (SE) of Active Distribution Networks (ADNs). The SE relies on the availability of data coming from Phasor Measurement Units (PMUs). The paper firstly illustrates the architecture of the experimental setup, then, by using a SE process developed by the Authors, based on the use of Iterated Kalman Filter (IKF), presents the experimental assessment of the time latencies of the whole process together with the SE accuracy assessment.
- P. Romano, M. Paolone, J. Arnold and R. Piacentini, An Interpolated-DFT Synchrophasor Estimation Algorithm and Its Implementation in an FPGA-based PMU Prototype, in Proc. of the 2013 IEEE PES General Meeting, Vancouver, July 21-25, 2013.
The accurate measurement of synchrophasors in static and dynamic power network conditions represents one of the main requirements of Phasor Measurement Units (PMUs). International Standards (i.e. the IEEE C37.118) are quickly evolving to drive the technological evolution of these intelligent electronic devices. In this respect, the paper presents an interpolated-DFT based synchrophasor-estimation algorithm that has been designed to meet the accuracy requirements of classes P and M defined in the recent IEEE Std C37.118-2011-1. Together with the analytical description of the main aspects of the proposed synchrophasor estimation algorithm, the paper also presents its implementation inside an FPGA-based PMU prototype. The paper finally shows and discusses some of the compliance tests of the proposed PMU prototype with respect to the above standard.
- Michael Hoefling, Florian Heimgaertner, Michael Menth, C-DAX: A Secure and Resilient Communication and Information Infrastructure for Power Grids, in Proc. 2012 Workshop on Renewable Energies, Smart Grid and Green ICT, Stuttgart, Germany, November 2012.
In this paper, we describe the C-DAX project. The main objective of the C-DAX project is to define and implement a novel and scalable information platform for implementing a cyber-secure data and control cloud for power grids, called CDAX. It will be validated to support various smart grid use cases and deployed for a trial in a live electricity network with real-world settings.
Other Dissemination Activities
- Presentation on the IFIP/IEEE International Workshop on the Management of Fog Computing and the Internet of Things (ManFIoT) of the paper Advanced Communication Modes for the Publish/Subscribe C-DAX Middleware, 29 April 2016, Istanbul, Turkey.
- Closing workshop on C-DAX as part of Energycon 2016, 4 April 2016, Leuven, Belgium. Agenda and slides can be retrieved here.
- Presentation on C-DAX on the IEEE symposium, 24 March 2016, Heverlee, Belgium.
- Presentation on C-DAX field trial and final results on the second FP7 SUNSEED workshop, 8 March 2016, The Hague, The Netherlands.
- Presentation on C-DAX at the Dagstuhl Seminar on Privacy and Security in Smart Energy Grids, 18-20 January 2016, Wadern, Germany.
- Presentation on C-DAX at the National Control System Security Center (CSSC) in Tagajo, Japan, 13 November 2015.
- Presentation on the IEEE Online GreenCom conference of the paper A Reservation Based Charging Management for On-the-move EV Under Mobility Uncertainty, 10-12 November 2015.
- Presentation on C-DAX on NI Days Eindhoven, 10 November 2015
- Demonstration of the C-DAX middleware and live view on the C-DAX field trial on the European Utility Week, 3-5 November 2015, Vienna, Austria.
- Presentation on the D-A-CH Conference on Energy Informatics (Energieinformatik 2015) of the paper jOSEF: A Java-Based Open-Source Smart Meter Gateway Experimentation Framework, November 2015, Karlsruhe, Germany.
- Publication of a case study on C-DAX - Building the Smart Grid - Secure Monitoring and Controlling of Power Grids Over the Internet - on the website of National Instruments, October 2015.
- Demonstration of the C-DAX middleware and live view on the C-DAX field trial on the iMinds Superminds event, 20 October 2015, Ghent, Belgium.
- Presentation of a poster on the C-DAX concept and the video of the C-DAX laboratory demo at the official handover of the grant approval for the project "Demonstrator Virtuelles Kraftwerk Neckar-Alb" (demonstration project of the virtual power plant for the region Neckar-Alb in Swabia, Germany), October 16, 2015, Reutlingen, Germany.
- Presentation on the NASPI Working Group meeting: Real-time monitoring of active distribution network using PMUs: requirements and real test cases, 14 October 2015, Chicago, USA
- Presentation of a poster for the paper Enabling Smart Grid Applications with ICN and demo of the C-DAX middleware and live view on the C-DAX field trial on the 2nd ACM Conference on Information Centric Networking, 30 September - 2 October 2015, San Francisco, California, USA.
- Presentation on the SGTech Europe 2015 conference of the C-DAX communication middleware and real-time state estimation and monitoring of distribution grids with PMUs, 22-24 September 2015, Amsterdam, The Netherlands.
- Presentation on Information Technology Society (ITG) Specialists Group 5.2.2 Workshop on New Challenges in Network Security (ITG-NHNS): The C-DAX Security Architecture for Smart Grids, September 24, 2015, Tuebingen, Germany
- Presentation on Information Technology Society (ITG) Specialists Group 5.2.1/5.2.4 Workshop on Cloud Networking: Resilience Levels for Reliable Smart Grid Communication over the C-DAX Cloud, September 24, 2015, Tuebingen, Germany.
- Article on Cyber-Security in Power Grids in Horizon, the EU Research & Innovation Magazine, presenting the results from two EU projects: C-DAX and SESAME, 18 September 2015
- Keynote by Prof. Mario Paolone on Real-Time State Estimation and the Internet of Substations on the NIWeek, August 6, 2015, Austin, Texas, USA.
- Presentation of the C-DAX concept during the ICNRG (Information-Centric Networking Group) working group meeting at 93rd IETF 2015), July 19-24 2015, Prague, Czech Republic.
- Presentation on the International Workshop on Communication Applications in Smart Grid (CAGS 2015) of the paper Securing the information infrastructure for EV charging, July 2015, Bradford, UK.
- Presentation on the IEEE International Conference on Communications (ICC 2015) of the paper Integration of IEEE C37.118 and Publish/Subscribe Communication, June 2015, London, UK.
- Presentation on the IEEE International Workshop on Security and Privacy for Internet of Things and Cyber-Physical Systems (IoT/CPS-Security 2015) collocated with the IEEE International Conference on Communications (ICC 2015) of the paper A Security Architecture for the Publish/Subscribe C-DAX Middleware, June 2015, London, UK.
- Presentation on PowerTech 2015 of the paper A Hardware-in-the-Loop Test Platform for the Performance Assessment of a PMU-based Real-Time State Estimator for Active Distribution Networks, 29 June - 2 July 2015, Eindhoven, The Netherlands.
- Short presentation of the C-DAX concept at AMA-SYSTEMS, May 4, 2015, Pforzheim, Germany.
- Presentation of the C-DAX concept at the workshop organized by the FP7 Sunseed project, March 25, 2015, Aalborg, Denmark.
- Presentation of the C-DAX concept at the NASPI workshop, March 2015, Burlingame, California, USA.
- Presentation of the C-DAX concept at the i-PCGRID conference, March 2015, San Francisco, California, USA.
- Presentation on the ITG/GI International Conference on Networked Systems (NetSys 2015) of the paper Enabling Resilient Smart Grid Communication over the Information-Centric C-DAX Middleware, March 2015, Cottbus, Germany.
- Presentation on the ITG/GI Workshop on Middleware for a Smarter Use of Electric Energy (MidSEE 2015) collocated with the ITG/GI International Conference on Networked Systems (NetSys 2015) of the paper Traffic Estimation of the PowerMatcher Application for Demand Supply Matching in Smart Grids, March 2015, Cottbus, Germany.
- Presentation on the 3rd International Conference on Connected Vehicles and Expo (ICCVE 2014) of the paper A Publish/Subscribe Communication Framework for Managing Electric Vehicle Charging, November 3-7, 2014, Vienna, Austria.
- Short presentation of the C-DAX concept during a main conference discussion panel at IEEE SmartGridComm 2014, November 4-6, Venice, Italy.
- Presentation on the IEEE 5th International Conference on Smart Grid Communications (SmartGridComm 2014) of the paper Low Latency Communication Infrastructure for Synchrophasor Applications in Distribution Networks, November 4-6, 2014, Venice, Italy.
- Presence on the booth of Alliander on the European Utility Week, November 4-6, 2014, Amsterdam, The Netherlands.
- Two technical presentations on the Managing Heterogeneous and Secure Communication Networks for Smart Grids workshop, part of IEEE SmartGridComm 2014, and participation in the roundtable discussion in the same workshop, November 3, Venice, Italy.
- Presentation of C-DAX and discussion with participants on the National Sustainability Congress, November 4, Den Bosch, The Netherlands.
- Presentation on the IEEE Workshop on Applied Measurements for Power Systems of the paper An Enhanced Interpolated-Modulated Sliding DFT for High Reporting Rate PMUs, September 24-26, 2014, Aachen, Germany.
- Security analysis conducted by RUN for Enexis and E laad: following contacts with the Dutch DSO Enexis and the foundation E-laad (an initiative of the joint Dutch DSOs to introduce public EV charge spots in the Netherlands), researchers from the Radboud University are carrying out a security analysis of the "Smart Charging" scheme being trialled in the Netherlands, incl. an analysis of various business models and the OCPP and OSCP protocols involved. As part of this analysis, the use of the C-DAX architecture is also investigated. Within C-DAX this already sparked off the investigation of ICN solutions for EV charging, presented in the publication at Q-ICN 2014 and in deliverable D3.3.
- Presentation on the International Workshop on Quality, Reliability, and Security in Information-Centric Networking (Q-ICN) of the paper Supporting Smart Electric Vehicle Charging with Information-Centric Networking, August 20, 2014, Rhodes, Greece.
- Presentation on the 18th Power Systems Computation Conference of the paper A Pre-Estimation Filtering Process of Bad Data for Linear Power Systems State Estimators using PMUs, August 18-22, 2014, Wroclaw, Poland.
- Presentation on the 18th Power Systems Computation Conference of the tutorial Information-Centric Communication Infrastructure for Real-Time State Estimation of Distribution Networks using Synchrophasor Measurements, August 18, 2014, Wroclaw, Poland.
- Presentation on the C-DAX project and the PMU-RTSE use case by Mario Paolone (EPFL) at the IEEE Dynamic Measurements Working Group, July 28, 2014.
- Presentation on the 13th International Conference on Probabilistic Methods Applied to Power Systems of the paper Probabilistic Methods Applied to Power Systems, July 7-10, 2014, Durham, United Kingdom (Winner of the Best Paper Award).
- Presentation of the C-DAX project and platform at the EnBW headquarter, June 4, 2014, Karlsruhe, Germany.
- Presentation on IEEE/IFIP Network Operations and Management Symposium (NOMS) 2014 conference of the paper Distributed Load Balancing for Resilient Information-Centric SeDAX Networks, May 7, 2014, Krakow, Poland
- Presentation on the C-DAX project and the PMU-RTSE use case by Mario Paolone (EPFL) on the Cigre Working Group C4.34 "Application of Phasor Measurement Units for Monitoring Power Systems" meeting, April 21, 2014.
- Presentation on the Workshop on Demand Modeling and Quantitative Analysis of Future Generation Energy Networks and Energy Efficient Systems (FGENET) of the paper A Perspective on the Future Retail Energy Market, March 17-19, 2014, Bamberg, Germany
- Presentation of the C-DAX project and the use of C-DAX for virtual power plants at the kick-off meeting for the cooperation network "Virtuelles Kraftwerk Neckar-Alb" (virtual power plant for the region Neckar-Alb in Swabia, Germany), January 21, 2014, Reutlingen, Germany.
- Presentation on SEGS 2013 workshop of the paper A Security Protocol for Information-Centric Networking in Smart Grids, November 8, 2013, Berlin, Germany
- Presentation on IEEE SmartGridComm 2013 conference of the paper Analyzing Storage Requirements of the Resilient Information-Centric SeDAX Architecture, October 22, 2013, Vancouver, Canada
- Keynote Speech by George Pavlou on the IFIP/IEEE 9th International Conference on Network and Service Management (CNSM) 2013: Information-centric Networking and In-network Cache Management: Overview, Trends and Challenges, October 14-18, 2013, Zurich, Switzerland
- Presentation on Siemens SCADA user group conference: Cyber-Secure Data and Control Cloud for Power Grids, October 9, 2013, Haarlem, The Netherlands
- Presentation on the Cigré Colloquium of the paper A Hardware-in-the-Loop Test Platform for the Real-Time State Estimation of Active Distribution Networks using Phasor Measurement Units, 6-9 October 2013, Yokohama, Japan.
- Overview presentation of the C-DAX project on the Smart Grid Conference, September 11, 2013, Trondheim, Norway
- Presentation on the 2013 IEEE PES General Meeting of the paper An Interpolated-DFT Synchrophasor Estimation Algorithm and its Implementation in an FPGA-based PMU Prototype, July 21-25, 2013, Vancouver, Canada.
- Article in Projects Magazine describing several Smart Grids project where iMinds is involved, including C-DAX.
- Presentation on Information Technology Society (ITG) Specialists Group 5.2.1 Workshop on Future Network Architectures: Storage Requirements for the Resilient Publish/Subscribe SeDAX Architecture, February 22, 2013, Stuttgart, Germany
- Presentation on 2012 Workshop on Renewable Energies, Smart Grid and Green ICT of the paper C-DAX: A Secure and Resilient Communication and Information Infrastructure for Power Grids, November 26, 2012, Stuttgart, Germany
- Presentation on the C-DAX project by Marcel Mampaey (Alcatel-Lucent) during the iMinds Conference in Ghent, Belgium (November 8, 2012).