publications List of publications related to I2Sim and Power System

For the most up to date publications please refer to Dr. Marti's Google Scholar page.

  • Title:Load decomposition at smart meters level using eigenloads approach

    Authors: H. Ahmadi, J. R. Martí

    Publication date: In Press

    Journal name: IEEE Transactions on Power Systems

    Abstract:The deployment of the advanced metering infrastructure (AMI) in distribution systems provides an excellent opportunity for load monitoring applications. Load decomposition can be done at the smart meters level, providing a better understanding of the load behavior at near-real-time. In this paper, loads’ current and voltage waveforms are processed offline to form a comprehensive library. This library consists of a set of measurements projected onto the eigenloads space. Eigenloads are basically the eigenvectors describing the load signatures space. Similar to human faces, every load has a distinct signature. Each load measurement is transformed into a photo and an efficient face recognition algorithm is applied to the set of photos. A list of all the on-line devices is always stored and can be accessed at any time. The proposed method can be implemented at the smart meters level. The distributed computation that can be achieved by performing simple calculations at each smart meter, without the need for sending intensive data to a central processor, is beneficial. From a system operator perspective, load composition in near-real-time provides the loads’ voltage dependence that are needed, for example, in Volt-VAR Optimization (VVO) in distribution systems. Further applications of load composition data are also discussed.

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  • Title:A framework for volt-VAR optimization in distribution systems

    Authors: H. Ahmadi, J. R. Martí, H. W. Dommel

    Publication date: 2015

    Journal name: IEEE Transactions on Smart Grid

    Abstract:The possibility of leveraging the data provided by smart meters to understand the load characteristics is studied in this paper. The loads are modeled as voltage-dependent elements to increase the accuracy of volt-VAR optimization (VVO) techniques for distribution systems. VVO techniques are part of the distribution management system (DMS) and may be used for purposes such as loss reduction, voltage profile improvement, and conservation voltage reduction (CVR). A deterministic framework is proposed that formulates the VVO problem as a mixed-integer quadratically constrained programming (MIQCP) problem, which is solved efficiently using advanced branch-andcut techniques. The proposed framework is capable of optimally controlling capacitor banks, voltage regulators, and ULTCs for day-ahead operation planning. The results indicate that loss reductions of up to 40% and a total demand reduction of up to 4.8% are achievable under some loading conditions in a radial test system. The effect of the load voltage dependence is also demonstrated through analytical simulations.

  • Title:Linear current flow equations with application to distribution systems reconfiguration

    Authors: A. Alsubaie, A. Di Pietro, J. Marti, and P. Kini

    Publication date: 2015

    Journal name: IEEE Transactions on Power Systems

    Abstract:Conventionally, power flow equations are used for distribution systems (DS) analysis to find the nodal voltages. For the particular form of the DS reconfiguration problem, however, a direct formulation in terms of branch flows allows a substantial increase in solution efficiency from an optimization point of view. In this paper, a set of linear current flow (LCF) equations are derived for DS. This formulation is then used within the network reconfiguration problem for loss minimization. A mixed-integer quadratically constrained programming (MIQCP) formulation, together with a mixed-integer linear programming (MILP) formulation are proposed in this paper and assessed through simulations. In these comparisons, the MILP formulation shows computational advantages over the MIQCP version and the preceding literature. The proposed methods are evaluated on several test systems.

  • Title:Minimum-loss network reconfiguration: a minimum spanning tree problem

    Authors: H. Ahmadi, J. R. Martí

    Publication date: 2015

    Journal name: Sustainable Energy, Grids and Networks

    Abstract:Topological reconfiguration of power distribution systems can result in operational savings by reducing the power losses in the network. In this paper, an efficient heuristic is proposed to find an initial solution for the minimum-loss reconfiguration problem with small optimality gap. Providing an initial solution for a mixed-integer programming (MIP) problem, known as “warm-start”, allows for a significant speed up in the solution process. The network reconfiguration for loss reduction is mapped here into a problem of finding a minimum spanning tree (MST) in a graph, for which there are a number of efficient algorithms developed in the literature. The proposed method leads to very fast solutions (less than 1.4 s for systems up to 10476 nodes). For the test systems considered, the solution provided by the proposed method lies within a relative optimality gap of about 2.2% with respect to the optimal solution. The existing MST algorithms guarantee the scalability of the proposed routine for large-scale distribution systems. Sensitivity factors are also employed to refine the solution to a smaller optimality gap.

  • Title:Mathematical representation of radiality constraint in distribution system reconfiguration problem

    Authors: H. Ahmadi, J. R. Martí

    Publication date: 2015

    Journal name: Int. J. Elect. Power & Energy Systems

    Abstract:Distribution systems are most commonly operated in a radial configuration for a number of reasons. In order to impose radiality constraint in the optimal network reconfiguration problem, an efficient algorithm is introduced in this paper based on graph theory. The paper shows that the normally followed methods of imposing radiality constraint within a mixed-integer programming formulation of the reconfiguration problem may not be sufficient. The minimum-loss network reconfiguration problem is formulated using different ways to impose radiality constraint. It is shown, through simulations, that the formulated problem using the proposed method for representing radiality constraint can be solved more efficiently, as opposed to the previously proposed formulations. This results in up to 30% reduction in CPU time for the test systems used in this study. Keywords: Distribution system reconfiguration, planar graph, dual graph, minimum spanning tree, radiality constraint, mixed-integer programming.

  • Title:Security-constrained unit commitment with linearized system frequency response constraints

    Authors: H. Ahmadi, J. R. Martí

    Publication date: 2014

    Journal name: IEEE Transactions on Power Systems

    Abstract:Rapidly increasing penetration level of renewable energies has imposed new challenges to the operation of power systems. Inability or inadequacy of these resources in providing inertial and primary frequency responses is one of the important challenges. In this paper, this issue is addressed within the framework of security-constrained unit commitment (SCUC) by adding new constraints representing the system frequency response. A modified system frequency response model is first derived and used to find analytical representation of system minimum frequency in thermal-dominant multi-machine systems. Then, an effective piecewise linearization (PWL) technique is employed to linearize the nonlinear function representing the minimum system frequency, facilitating its integration in the SCUC problem. The problem is formulated as a mixed-integer linear programming (MILP) problem which is solved efficiently by available commercial solvers. The results indicate that the proposed method can be utilized to integrate renewable resources into power systems without violating system frequency limits.

  • Title: A Platform for Disaster Response Planning with Interdependency Simulation Functionality

    Authors: A. Alsubaie, A. Di Pietro, J. Marti, and P. Kini

    Publication date: 2013

    Journal name: Crit. Infrastruct. Prot. VII

    Abstract:Abstract Catastrophic events can result in great loss of lives and property. Planning an effective disaster response to minimize associated losses is a fundamental challenge for decision makers. The planning process can be improved by simulating interdependent critical infrastructures and evaluating system behavior during disaster scenarios. This paper describes a disaster response planning simulation platform that supports decision making based on the interdependencies existing between a power grid and a supervisory control and data acquisition (SCADA) system. By considering the physical constraints on the power grid and SCADA network, a set of feasible configurations is presented to disaster responders. The utility of the platform is demonstrated using an example scenario involving power distribution to a hospital during a disaster event.


    Authors: V. Formicola, A. Di Pietro, A. Alsubaie, S. D’Antonio, and J. R. Martí

    Publication date: 2014

    Journal name: Crit. Infrastruct. Prot. VIII

    Abstract:Abstract This paper describes a next-generation security information and event management (SIEM) platform that performs real-time impact assessment of cyber attacks that target monitoring and control systems in interdependent critical infrastructures. To assess the effects of cyber attacks on the services provided by critical infrastructures, the platform combines security analysis with simulations produced by the Infrastructure Interdependencies Simulator (I2Sim). The approach is based on the mixed holistic reductionist (MHR) methodology that models the relationships between functional components of critical infrastructures and the provided services. The effectiveness of the approach is demonstrated using a scenario involving a dam that feeds a hydroelectric power plant. The scenario considers an attack on a legacy SCADA system and wireless sensor network that reduces electricity production and degrades the services provided by interdependent systems. The results demonstrate that the attack is detected in a timely manner, risk assessment is performed effectively and service level variations can be predicted. The paper also shows how the impact of attacks on services can be estimated when limits are imposed on information sharing.

  • Title:Distribution System Restoration Considering Critical Infrastructures Interdependencies

    Authors: H. Ahmadi, A. Alsubaie, and J. R. Martí

    Publication date: 2014

    Conference name: 2014 IEEE Power & Energy Society General Meeting

    Abstract:Abstract—Resource management is a crucial task during natural or man-made disasters to maximize the number of saved lives. As part of the vital resources, electricity restoration has a high priority for increasing the performance of critical infrastructures such as hospitals and water pumping stations. Also, the interdependencies between these infrastructures have to be taken into account in the process of service restoration to ensure their maximum operational capacity. In this paper, the problem of service restoration in a distribution system to maximize the operational capacity of a hospital is formulated. Different case studies are considered to show the effectiveness of the proposed method under a variety of emergency situations.

  • Title:Resources Allocation in Disaster Response using Ordinal Optimization Based Approach

    Authors: A. Alsubaie, K. Alutaibi, J. R. Martí, A. Di Pietro, and A. Tofani

    Publication date: 2014

    Conference name: IEEE Canada International Humanitarian Technology Conference (IHTC 2014)

    Abstract:Abstract—Recent events, such as Hurricane Katrina, have revealed the need for coordinated and effective disaster responses. An optimal distribution of available resources is essential for disaster response effectiveness. Emergency responders are faced with the challenges of increased size and complexity of critical infrastructures that provide vital resources for disaster response operations. In this paper, we propose a simulation-based tool to assist emergency responders in finding the optimal distribution of available resources during a disaster event. The proposed tool utilizes the Disaster Response Network Enabled Platform (DRNEP) which is an infrastructure interdependencies simulation platform for disaster response support. DR-NEP is a simulation network platform that integrates different simulators for different infrastructures to form a universal simulation platform. We employ a new concept in Discrete Event Systems optimization called Ordinal Optimization to address the problem of resources allocation during a disaster event. The objective of the optimization problem is maximizing the operational capacity of a critical infrastructure, a hospital in this case. Due to the huge combinatorial feasible search space, an Ordinal Optimization based approach is used to solve the problem using two main concepts: goal softening and order comparison. This approach aims at finding a Good Enough solution set (G) with an acceptable probability and efficient computational effort. This paper describes early results of our work that shows the use of our approach in optimizing resources allocation in a simulated disaster event.

  • Title:Infrastructure Interdependencies Concept and its Application to Disaster Management in Hajj and Umrah

    Authors: A. Alsubaie, K. Alutaibi, M. Khouj, and J. R. Martí

    Publication date: 2014

    Journal name: Scientific Forum XIV for Hajj and Umrah Research


    Abstract:Abstract- Annual pilgrimage to Makkah (Hajj) poses a challenge to the Saudi authorities. Disaster management planning is a difficult task for emergency responders in Hajj. This paper introduces the concept of infrastructure interdependencies to the area of Hajj Disaster Management. It explains the basic concepts, techniques and challenges of its applications. Also, it proposes the use of input-output simulation models in building a Decision Support System for its application in Hajj disaster management.

  • Title: Combined adverse effects of cascading events on systems' functionality: an insular case study, French West Indies

    Authors: Nicolas Desramaut, Justin Wang, Pierre Gehl, Jose Marti, Audrey Baills, Arnaud Reveillere

    Publication date: 2013/4

    Conference name: EGU General Assembly Conference Abstracts



    Abstract:Abstract In our modern societies, lifelines play a vital role, even in normal conditions. Therefore, during crises, the dependency to critical infrastructures is likely to be exacerbated. Indeed, in order to provide quick emergency services to the population, systems have to be functional. However, even if not directly damaged, in order to be functional, elements of the different systems have to receive enough resources but also to be able to supply their own services.

  • Title:Reduction techniques in modelling critical infrastructures under the infrastructure interdependencies simulator framework

    Authors: Arvind Singh, Krishan D Srivastava, Jose R Marti

    Publication date: 2013/1/1

    Journal name: International journal of critical infrastructures




    Publisher:Inderscience Publishers

    Abstract:Modern, urban population centres are comprised of highly interdependent networks of infrastructures. In normal operating conditions, these interdependencies can be neglected without much trouble, however, in times of emergency, these same interdependencies, often hidden, can debilitate relief efforts. The effects are often noted in disaster response post– mortems as poor distribution of resources and previously unseen vulnerabilities in the system.

  • Title: Road Traffic Forecasting through Simulation and Live GPS-Feed from Intervehicle Networks

    Authors: Hafiz Abdur Rahman, Jose R Marti, KD Srivastava

    Publication date: 2012/10/21

    Conference name: Global Humanitarian Technology Conference (GHTC), 2012 IEEE



    Abstract:Abstract Any disaster management requires sending emergency aids to the affected areas in an earliest possible time. In urban areas, high traffic volume is an impediment for efficient transportation of such goods and services. In this paper, we present a traffic flow forecasting model that may help emergency service delivery. In our approach, we used a microscopic traffic simulator with live vehicle statistics collected from intervehicle networks.

  • Title: Inter-System Software Adapter for Decision Support by Interfacing Disaster Response Platforms & Simulation Platforms

    Authors: Jose Marti, Pranab Kini, Paul Lusina, Antonio Di Pietro, Vittorio Rosato, Baptiste Charnier, Wang Kui

    Publication date: 2012/10/21

    Conference name: Global Humanitarian Technology Conference (GHTC), 2012 IEEE



    Abstract:Abstract An inter-system adapter design is described which links the web service based DR NEP and WebSimP simulation platforms. The adapter enables the PSS Sincal electrical simulator to share results with the DR NEP which coordinates the data exchange among interdependent simulators. In this paper, we describe an adapter which supports decision makers involved in natural crisis management by calculating constraints on electrical loads based on the state of the electrical grid.

  • Title:Optimal Decision Maker Algorithm for Disaster Response Management with I2Sim Applications

    Authors: Kui Wang, Ming Bai, Jose Marti, KD Srivastava

    Publication date: 2012/4

    Journal name: Proceedings of the 9th International ISCRAM Conference–Vancouver


    Abstract:Disaster response management has become an important area of research in recent years, with authorities spending more resources in the area. Infrastructure resource interdependencies are key critical points for a system to operate optimally. After a disaster occurs, infrastructures would have sustained certain degrees of damage, the allocation of limited resources to maximize human survival becomes a top priority.

  • Title:Power management in disasters: Application of loadshedding and wind turbine controller

    Authors: Shahrzad Rostamirad, Kui Wang, Jose R Marti

    Publication date: 2011/5/8

    Conference name: Electrical and Computer Engineering (CCECE), 2011 24th Canadian Conference on



    Abstract:Electric infrastructure is vulnerable to damage during disasters and the downstream microgrid may be left without electricity for a long time. Even networks with distributed generators (DG) will fail due to immediate frequency fluctuations that are the results of mismatch between electrical demand and generation. This paper studies the campus of The University of British Columbia's electrical network, and analyses its future expansion needs in terms of expanded local generation to meet the demand growth.

  • Title: Real-time monitoring of energy infrastructure

    Authors: Cesar Lopez, Paul Lusina, José R Martí

    Publication date: 2011/5/8

    Conference name: Electrical and Computer Engineering (CCECE), 2011 24th Canadian Conference on



    Abstract:Many legacy infrastructures are reaching the end of their service life. The necessary replacement of this infrastructure creates an opportunity to replace them with environmental and innovative systems. In this paper, a Smart Energy Micro Grid (SEMG) simulator is developed to model thermal energy alternatives for a large Canadian university. The simulator allows real-time resource management using hourly historical operational data.

  • Title:Disaster management in real time simulation using machine learning

    Authors: Mohammed Khouj, Cesar Lopez, Sarbjit Sarkaria, José Marti

    Publication date: 2011/5/8

    Conference name: Electrical and Computer Engineering (CCECE), 2011 24th Canadian Conference on



    Abstract:A series of carefully chosen decisions by an Emergency Responder during a disaster are vital in mitigating the loss of human lives and the recovery of critical infrastructures. In this paper we propose to assist a human Emergency Responder by modeling and simulating an intelligent agent using Reinforcement Learning. The goal of the agent will be to maximize the number of patients discharged from hospitals or on-site emergency units.

  • Title:A canonical data model for simulator interoperation in a collaborative system for disaster response simulation

    Authors: Marco A Gonzalez, José R Martí, Philippe Kruchten

    Publication date: 2011/5/8

    Conference name: Electrical and Computer Engineering (CCECE), 2011 24th Canadian Conference on



    Abstract:The Disaster Response Network Enabled Platform (DRNEP) is a system that integrates a set of independently developed infrastructure and disaster simulators. This paper describes some of the architectural choices that we made for DRNEP. The overall system uses a master-slave pattern, with one master simulator orchestrating all of the others, based on a central system clock.

  • Title:Infrastructure interdependencies simulation through matrix partitioning technique

    Authors: Hafiz Abdur Rahman, Mazana Armstrong, Jose R Marti, KD Srivastava

    Publication date: 2011/1/1

    Journal name: International Journal of Critical Infrastructures




    Publisher:Inderscience Publishers

    Abstract:In recent years, there has been considerable interest in modelling and simulating interdependencies among critical infrastructures. For most cases, agent-based frameworks are employed for these types of simulation. In this paper, we present a new approach for interdependencies simulation that we have used in the infrastructures interdependencies simulator (I2Sim). I2Sim implementation is based on the matrix partitioning technique named multi-area Thevenin equivalent (MATE).

  • Title:Identification of sources of failures and their propagation in critical infrastructures from 12 years of public failure reports

    Authors: Hafiz Abdur Rahman, Konstantin Beznosov, José R Martí

    Publication date: 2009/1/1

    Journal name: International Journal of Critical Infrastructures




    Publisher:Inderscience Publishers

    Abstract:Understanding the origin of infrastructure failures and their propagation patterns in critical infrastructures can provide important information for secure and reliable infrastructure design. Among the critical infrastructures, the Communication and Information Technology Infrastructure (CITI) is crucial, as it provides the basic mechanism for sharing information among all infrastructures. Failures in CITI can disrupt the effective functionality of the other critical infrastructures.

  • Title:I2Sim: a matrix-partition based framework for critical infrastructure interdependencies simulation

    Authors: Hafiz Abdur Rahman, Mazana Armstrong, DeTao Mao, José R Martí

    Publication date: 2008/10/6

    Conference name: Electric Power Conference, 2008. EPEC 2008. IEEE Canada



    Abstract:In the recent years, there has been considerable interest in modeling and simulating interdependencies among critical infrastructures. For most cases, agent-based frameworks are employed for these types of simulation. In this paper, we have presented a new approach for interdependency simulation that we implemented in our infrastructure interdependency simulator (I2Sim). This is based on matrix partition-based technique named multi-area Thevenin equivalent (MATE).

  • Title:I2Sim modelling and simulation framework for scenario development, training, and real-time decision support of multiple interdependent critical infrastructures during large emergencies

    Authors: José Martí, Carlos Ventura, Jorge Hollman, K Srivastava, Hugón Juárez

    Publication date: 2008/10

    Journal name: NATO (OTAN) MSG-060 Symposium on” How is Modelling and Simulation Meeting the Defence Challenges out to


    Abstract:Effective response during large disasters (eg, earthquakes, hurricanes, terrorist attacks) requires a close coordination of a wide range of resources across multiple infrastructures (eg, power grid, water system, telecommunication network, transportation system, etc.). Due to the diversity of private/public entities that need to work together, classical C2 (Command-and-Control) strategies cannot be applied and have to be replaced by C2'(Coordination-and-Control) strategies.

  • Title: Infrastructure Interdependencies Simulation (I2Sim) Team

    Authors: José R Martí

    Publication date: 2007

    Conference name: Electrical and Computer Engineering (CCECE), 2011 24th Canadian Conference on



    Abstract:S. Prasad, "PC-Cluster Simulator for Joint Infrastructure Interdependencies Studies". The University of Bristish Columbia, August 2007. ... L. Liu, "Prototyping and Cells Modelling of the Infrastructures Interdependencies Simulator I2Sim". The University of Bristish Columbia, August 2007. ... M. Sotoodeh, "Ontology-based semantic interoperability in Emergnecy Management". The University of Bristish Columbia, July 2007. ... J. Martí, J. Hollman, C. Ventura, J. Jatskevich. Dynamic recovery of critical infrastructures: Real-time temporal coordination.