A web interface for meta-heuristics based grid schedulers

The use of meta-heuristics for designing efficient Grid schedulers is currently a common approach. One issue related to Grid based schedulers is their evaluation under different Grid configurations, such as dynamics of tasks and machines, task arrival, scheduling policies, etc. In this paper we present a web application that interfaces the final user with several meta-heuristics based Grid schedulers. The application interface facilities for each user the remote evaluation of the different heuristics, the configuration of the schedulers as well as the configuration of the Grid simulator under which the schedulers are run. The simulation results and traces are graphically represented and stored at the server and can retrieved in different formats such as spreadsheet form or pdf files. Historical executions are as well kept enabling a full study of use cases for different types of Grid schedulers. Thus, through this application the user can extract useful knowledge about the behavior of different schedulers by simulating realistic conditions of Grid system without needing to install and configure any specific software.Peer ReviewedPostprint (published version

A study on the performance of Oracle Grid Engine for computing intensive applications

(c) 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Computing intensive applications are an important family of applications in distributed computing domain. They have been object of study using different distributed computing paradigms and infrastructures. Such applications distinguish for their demanding needs for CPU computing, independently of the amount of data associated with the problem instance. Among computing intensive applications, there are applications based on simulations, aiming to maximize system resources for processing large computations for simulation. In this paper, we consider an application that simulates scheduling and resource allocation in a Grid computing system using Genetic Algorithms. In such application, a rather large number of simulations is needed to extract meaningful statistical results about the behaviour of the simulation results. We study the performance of Oracle Grid Engine for such application running in a Cluster of high computing capacities. Several scenarios were generated to measure the response time and queuing time under different workloads and number of nodes in the cluster.Peer ReviewedPostprint (author's final draft

A static benchmarking for grid scheduling problems

Analysis of algorithms for Grid computing systems before deployment in real Grid infrastructures is an important issue in Grid computing domain. Due to the complexity of real Grid systems, assessing performance analysis of optimization algorithms such as scheduling algorithms, is in general difficult, costly and time consuming. Benchmarking and simulation are two most used alternatives for analyzing optimization algorithms in Grid systems before deployment. In this paper we present a static benchmarking for scheduling problems in Grid systems. The benchmarking has been generated using the HyperSim-G Grid simulator and captures several types of Grid systems based on combinations of different machine and task types. Instances have six different sizes ranging from tiny (32 machines/512 tasks) to extra large size (1024 machines/16384 tasks) and are grouped according to machine and task types. The benchmark suite, consisting of about 720 instances, is offered through a web pagePeer ReviewedPostprint (published version

Real-Time Digital Simulators: A Comprehensive Study on System Overview, Application, and Importance

The multifarious improvements in computational and simulation tools have brought tremendous progress in the field of designing, testing and analyzing technologies. In this paper, the technological aspects and the concept of modern real-time digital simulators are presented. The real-time simulator functions in real time, thus it produces continuous output that realistically represents the conditions of a real system. Also, in a real-time simulator the user can test physical devices. Therefore, it is of great importance to understand the features and roles of the advanced simulator technologies. Also, User-friendly system interface, easy application in system design and testing, and most importantly cost effectiveness are the most desire features for implying these simulator into a research. Therefore, this paper summarizes all significant features by considering the above-mentioned facts of some most popular, globally, and commercially available simulator technologies. Real Time Digital Simulators (RTDS), OPAL-RT, Network Torsion Machine Control (NETOMAC), dSPACE, Real-Time solution by MathWorks (xPC target, Real-Time Windows target), Power_system Online_simulation Unveil Your Analysis (POUYA) Simulator and Typhoon HIL Simulator are discussed in this review paper based on the accessibility of information. A summarization of these simulators’ background, hardware, software and communication protocols are presented. Applications of these above-mentioned simulators are also added to understand the potentials of these simulators

Network and System Management using IEC 62351-7 in IEC 61850 Substations: Design and Implementation

Substations are a prime target for threat agents aiming to disrupt the power grid’s operation. With the advent of the smart grid, the power infrastructure is increasingly being coupled with an Information and Communication Technologies (ICT) infrastructure needed to manage it, exposing it to potential cyberattacks. In order to secure the smart grid, the IEC 62351 specifies how to provide cybersecurity to such an environment. Among its specifications, IEC 62351-7 states to use Network and System Management (NSM) to monitor and manage the operation of power systems. In this research, we aim to design, implement, and study NSM in a digital substation as per the specifications of IEC 62351-7. The substation is one that conforms to the IEC 61850 standard, which defines how to design a substation leveraging ICT. Our contributions are as follows. We contribute to the design and implementation of NSM in a smart grid security co-simulation testbed. We design a methodology to elaborate cyberattacks targeting IEC 61850 substations specifically. We elaborate detection algorithms that leverage the NSM Data Objects (NSM DOs) of IEC 62351- 7 to detect the attacks designed using our method. We validate these experimentally using our testbed. From this work, we can provide an initial assessment of NSM within the context of digital substations

Network and System Management for the Security Monitoring of Microgrids using IEC 62351-7

Interest in adding renewable energy sources to the power grid has risen substantially in recent years. As a response to this growing interest, the deployment of microgrids capable of integrating renewable energy has become more widespread. Microgrids are independent power systems that deliver power from different kinds of Distributed Energy Resources (DERs) to local energy consumers more efficiently than the conventional power grid. The microgrid leverages advanced information and communication technologies for vital protection, monitoring, and control operations as well as for energy management. With the use of information technology comes the need to protect the microgrid information layer from cyberattacks that can impact critical microgrid power operations. In this research, a security monitoring system to detect cyberattacks against the microgrid, in near-real time, is designed and implemented. To achieve this, the system applies Network and System Management (NSM) for microgrid security monitoring, as specified by the IEC 62351-7 security standard for power systems. The specific contributions of this research are (i) an investigation on the suitability of NSM for microgrid security monitoring; (ii) the design and implementation of an NSM platform; (iii) the design and implementation of a security analytics framework for NSM based on deep learning models; (iv) the elaboration of a comprehensive microgrid simulation model deployed on a Hardware in the Loop (HIL) co-simulation framework; and (v) an experimental evaluation on the effectiveness and scalability of the NSM security monitoring platform for detection against microgrid attack scenarios, with a methodology being used to systematically generate the scenarios. The experimental results validate the usefulness of NSM in detecting attacks against the microgrid

Contributions à la modélisation et à la validation des modèles de liaisons HVDC de Type VSC-MMC dans les outils de simulation temps réel

RÉSUMÉ Le développement des réseaux de transport d'électricité est actuellement en pleine mutation. La transition énergétique en cours depuis plusieurs années, se concrétise par la fermeture de nombreuses centrales de production au charbon ou au fioul, l'installation massive de centres de production éolien et photovoltaïque et enfin une stagnation, voire une diminution de la consommation d'électricité. Cette transition impacte tous les pays d'Europe si bien que les interconnexions sont de plus en plus soumises aux variations des productions renouvelables. Cette évolution de la consommation et de la production impose l'installation de systèmes de contrôle des flux de puissance plus sophistiqués que ceux utilisés jusqu'à maintenant. On parle donc de plus en plus d'équipement à base d'électronique de puissance : liaisons à courant continu à haute tension (CCHT ou HVDC) et compensateur statique de puissance réactive. Les liaisons HVDC permettent en plus de répondre à la demande sociétale d'enfouir les ouvrages de transport d'électricité. Les réseaux de transport voient donc de plus en plus d'intégration de liaisons HVDC point à point. Le plan de développement du réseau européen ENTSO-E prévoit ainsi plus de 20 000 km de liaisons HVDC en 10 ans. Avec ce développement dans des zones relativement limitées (réseaux nationaux autour de la mer du Nord par exemple : Royaume Uni, France, Belgique, Pay-Bas, Danemark, Allemagne), la notion de réseaux à courant continu commence à se poser. Plusieurs projets de ce type de réseaux sont actuellement en cours d'étude de manière très avancée en Europe. En Chine deux réseaux HVDC sont désormais en exploitation. Depuis maintenant plus de 20 ans, des liaisons VSC (Voltage Source Converter) à base de composants IGBT (Insulated Fate Bipolar Transistor) ou GTO (Gate Turn Off Thyristor) ont commencé à être installées. Elles étaient initialement synonymes d’onduleur autonome à modulation de largeurs d’impulsions et les commutations étaient réalisées à des fréquences de quelques centaines de Hz (voire quelques kHz pour les IGBT). La difficulté d’assembler des centaines de GTO/IGBT et de diodes en série pour former des valves à très haute tension (plus de 100 kV) et/ou le besoin de maîtriser les pertes par commutation dissipées dans ses convertisseurs ont conduit les constructeurs à privilégier des structures modulaires où de nombreux modules sont connectés en cascade. Les convertisseurs à multi-niveaux (MMC - Modular Multilevel Converter) vont de quelques dizaines de niveaux à plusieurs centaines en fonction de la technologie et du niveau de tension.----------ABSTRACT Development of electrical transmission grids is presently undergoing radical changes. The energy transition towards renewable energy started a few years ago. It leads to closure of many coal-fired or oil-fired power plants, massive construction of photovoltaic plants and wind farms and a stagnation of electrical consumption. This transition has a huge impact in Europe on the electrical interconnections between countries. Sophisticated equipment to control power flow are now more and more required in this context. Power electronic based devices are often selected such as High-Voltage Direct Current transmission systems (HVDC) and Static Var Compensator (SVC). HVDC also offers a practical solution to the public demand to use underground cables instead of overhead lines. More and more HVDC point-to-point link are now integrated in transmission grids. More than 20,000 km of HVDC lines are expected in the 10-year ENTSO-E development plan. This development will occur in a limited area in Europe (national grid around the North Sea: United Kingdom, France, The Netherlands, Denmark, Germany) providing an opportunity to design HVDC grids. Several HVDC grids projects are now planned in Europe. In China, 2 HVDC grids are already in operation. Voltage Source Converters (VSC) have been installed on transmission grids for more than 20 years. They have been limited until 2010 to the two-level and three level diode-clamped topology with switching frequencies around a few kHz. Several practical limitations as switching losses and difficulties in assembling very high voltage valves have been overcome by the modular technology called MMC (Modular Multilevel Converter). This topology consists of several sub-modules (SM) connected in series. Number of SMs per valve can go from a few tenth to several hundreds. MMC is now the quasi exclusive solution for AC/DCCC conversion on transmission grids in Europe. Technical solutions up to 400 kV and even 500kV DC are under construction. In order to prepare the installation and analyze the behavior of MMC converters connected to grids with high penetration of power electronics based devices, reliable and accurate simulation tools are required. Electromagnetic Transient (EMT) tools are usually used in this context because they handle a detailed representation of converters and control systems. In addition to EMT offline simulation, real-time simulation with HVDC control systems replicas becomes more and more popular. This is why, real-time simulation laboratories with replicas have been constructed or are planned in most of areas where HVDC is massively installed

Power System Digital Twins and Real-Time Simulations in Modern Grids

Power systems are in a state of constant change with new hardware, software and applications affecting their planning, operation, and maintenance. Power system control centers are also evolving through new technologies and functionalities to adapt to current needs. System control rooms have moved from fully manual to automated operations, from analog to digital, and have become an embedded and complex information, communication, computation and control system. Digital twins are virtual representations of physical systems, assets and/or processes. They are enabled through software, hardware and data integration, and allow real-time monitoring, controlling, prediction, optimization, and improved decision-making. Consequently, digital twins arise as a technology capable of incorporating existing control systems along with new ones to collect, classify, store, retrieve and disseminate data for the future generation of control centers. Power system digital twins (PSDTs) can uplift how data from power grids and their equipment is processed, providing operators new ways to visualize and understand the information. Nevertheless, complexity and size of modern power systems narrow the scope a current digital twin can have. Furthermore, the services provided are limited to only certain phenomena and/or applications. This thesis addresses the need for a flexible and versatile solution that is also robust and adaptable for monitoring, operating and planning future power systems. The modular design for implementation of the next generation of PSDTs is proposed based on grid applications and/or services they can provide. From a modeling perspective, this thesis also distinguishes how real-time simulations enable the design, development, and operation of a PSDT. First, the need for enhanced power system modeling and simulation techniques is established. Moreover, the necessity of expanding to a more complete and varied open-source library of power system models is identified. The thesis continues by designing, developing, and testing models of inverter-based resources that can be used by the industry and researchers when developing PSDTs. Furthermore, the first-of-its-kind synthetic grid with a longitudinal structure, the S-NEM2300-bus benchmark model, based on the Australian National Electricity Market is created. The synthetic grid is, finally, used to illustrate the first steps towards implementing a practical PSDT

A graphics driven approach to discrete event simulation.

This thesis investigates the potential of computer graphics in providing for a graphics driven specification system that gives sufficient structure and content to form the simulation model itself. The nature of discrete event simulation modelling, the diagramming method of activity cycle diagrams which underpinned this research, the three phase simulation model structure, and the trend of visual simulation modelling are discussed as the basis for the research. Some current existing simulation languages and packages are reviewed, which gives insight into the essential features of an ideal computer simulation environment. The basic research method adopted was to build systems that exemplified the state of thinking at the time. The purpose of this method was to enable ideas to be developed, discarded and enhanced, and for new ideas to emerge. The research has undergone a series of application developments on the Apple Macintosh to examine the advantages and limitations of such systems. The first system developed during the research, MacACD, provides the basis for proposals concerning the enhancement of the ACD diagramming method in a computer-aided environment. However, MacACD demonstrated the limitations of an ACD interface and the need for a more flexible specification system. HyperSim, a simulation system developed using HyperCard, has all the power of interconnectivity demonstrated as a need by MacACD, but has severe limitations both in terms of security of system development, and an inability to provide a running model directly due to lack of speed. However, the power of an icon-based interconnected textual and diagrammatic based system were demonstrated by the construction of this system during this research, and led to the development of the final system described in this thesis : MacGraSE. The development of this system during this research incorporates many innovations. The main input device is a picture representing the problem, including a background display. This system allows for dynamic icon based visual model running, as well as code generation for complete model embellishments, interactive report writing, and representational graphics outputs