Towards a Realistic Model for Failure Propagation in Interdependent Networks

Modern networks are becoming increasingly interdependent. As a prominent example, the smart grid is an electrical grid controlled through a communications network, which in turn is powered by the electrical grid. Such interdependencies create new vulnerabilities and make these networks more susceptible to failures. In particular, failures can easily spread across these networks due to their interdependencies, possibly causing cascade effects with a devastating impact on their functionalities. In this paper we focus on the interdependence between the power grid and the communications network, and propose a novel realistic model, HINT (Heterogeneous Interdependent NeTworks), to study the evolution of cascading failures. Our model takes into account the heterogeneity of such networks as well as their complex interdependencies. We compare HINT with previously proposed models both on synthetic and real network topologies. Experimental results show that existing models oversimplify the failure evolution and network functionality requirements, resulting in severe underestimations of the cascading failures.Comment: 7 pages, 6 figures, to be published in conference proceedings of IEEE International Conference on Computing, Networking and Communications (ICNC 2016), Kauai, US

The Economics of Wind Power with Energy Storage

We develop a nonlinear mathematical optimization program for investigating the economic and environmental implications of wind penetration in electrical grids and evaluating how hydropower storage could be used to offset wind power intermittence. When wind power is added to an electrical grid consisting of thermal and hydropower plants, it increases system variability and results in a need for additional peak-load, gas-fired generators. Our empirical application using load data for Alberta’s electrical grid shows that 32% wind penetration (normalized to peak demand) results in a net cost increase of $C5.20/ MWh, while 64$12.50/MWh. Costs of reducing CO2 emissions are estimated to be $41-$56 per t CO2 . When pumped hydro storage is introduced in the system or the capacity of the water reservoirs is enhanced, the hydropower facility could provide most of the peak load requirements obviating the need to build large peak-load gas generators.Renewable energy, carbon costs, hydropower storage, mathematical programming

Reactive point processes: A new approach to predicting power failures in underground electrical systems

Reactive point processes (RPPs) are a new statistical model designed for predicting discrete events in time based on past history. RPPs were developed to handle an important problem within the domain of electrical grid reliability: short-term prediction of electrical grid failures ("manhole events"), including outages, fires, explosions and smoking manholes, which can cause threats to public safety and reliability of electrical service in cities. RPPs incorporate self-exciting, self-regulating and saturating components. The self-excitement occurs as a result of a past event, which causes a temporary rise in vulner ability to future events. The self-regulation occurs as a result of an external inspection which temporarily lowers vulnerability to future events. RPPs can saturate when too many events or inspections occur close together, which ensures that the probability of an event stays within a realistic range. Two of the operational challenges for power companies are (i) making continuous-time failure predictions, and (ii) cost/benefit analysis for decision making and proactive maintenance. RPPs are naturally suited for handling both of these challenges. We use the model to predict power-grid failures in Manhattan over a short-term horizon, and to provide a cost/benefit analysis of different proactive maintenance programs.Comment: Published at http://dx.doi.org/10.1214/14-AOAS789 in the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

State Estimatation in Smart Grids

Avrupa Metroloji Araştırma Programı (EMRP) altında 2013 yılında açılan “Enerji ve Çevre Çağrısı” kapsamında “ENG63 Sensor Network Metrology for the Determination of Electrical Grid Charecteristics (Elektriksel Şebeke Karakteristiklerinin Belirlenmesi İçin Sensör Ağ Metrolojisi)” isimli bir proje başlatılmıştır. Bu proje, 2013 yılında tamamlanan “Smart Electrical Grid for Metrology” isimli EMRP projesinin devamı niteliğinde bir projedir. Bu proje ile geliştirilen matematiksel ve istatiksel prosedürler ve güvenlik ölçümleri, şebekenin monitör edilmesi ve kontrolünün sağlanması amacıyla kullanılan sensör ağlarının ileri seviyede ölçümleri için gereklidir. Bu prosedürler, yüksek maliyette cihaz ihtiyacını da azaltacaktır. Ayrıca, mevcut şebekelerin yapısının belirlenmesi ve dağıtım hatları ve kontrollü yüklerde kullanımının optimize edilmesi amacıyla yeni teknikler geliştirilecektir. Proje kapsamında, TÜBİTAK UME diğer Metroloji Enstitüleri ile birlikte çeşitli iş paketlerini paylaşacak ve geliştirilecek olan şebeke durum tahmini ve sensör yerleşim algoritmalarının farklı elektrik şebekelerinde test edilmesini sağlayacaktır. Bu bildiride, “Sensor Network Metrology for the Determination of Electrical Grid Charecteristics” projesi kapsamında yapılacak olan çalışmalar hakkında bilgi verilecektir. A project named “ENG63 Sensor Network Metrology for the Determination of Electrical Grid Characteristics” has just started in the frame of Energy and Envoriment call in European Metrology Research Programme (EMRP) 2013. This project is a follow-up project of another EMRP project named "Smart Electrical Grid for Metrology" which was completed on 2013. Mathematical and statistical procedures and security measures are required for advanced measurement sensor networks used for grid monitoring and control. Such procedures will minimize the need for costly instrumentation. In addition, techniques must be developed to determine the structure of existing grids and to optimise their use of distributed generation and controllable loads. In this project, TÜBİTAK UME will colloborate in some work packages with other National Metrology Institutes and will provide testing of state estimatation and sensor placement algoritms in different distrubution grids. In this paper, the aim, need, workpages and the deliverables of the "Sensor Network Metrology for the Determination of Electrical Grid Characteristics" project will be given

Hardware-in-the-loop grid simulator system and method

A hardware-in-the-loop (HIL) electrical grid simulation system and method that combines a reactive divider with a variable frequency converter to better mimic and control expected and unexpected parameters in an electrical grid. The invention provides grid simulation in a manner to allow improved testing of variable power generators, such as wind turbines, and their operation once interconnected with an electrical grid in multiple countries. The system further comprises an improved variable fault reactance (reactive divider) capable of providing a variable fault reactance power output to control a voltage profile, therein creating an arbitrary recovery voltage. The system further comprises an improved isolation transformer designed to isolate zero-sequence current from either a primary or secondary winding in a transformer or pass the zero-sequence current from a primary to a secondary winding

An Integrated Green Urban Electrical Grid

This Article will discuss the vision of a new green urban grid that relies on decentralized generation and storage, energy efficiency, and demand response. Much of the literature focuses on the development of aspects of the green grid, such as energy efficiency, without consideration of how these resources should be integrated to effectively reduce greenhouse gas emissions and pollution, maintain reliability, and create economic opportunity. After discussing the components of the green urban grid, this Article will discuss why integrating these components is essential to meeting renewable policy goals, and finally, this Article will discuss steps that regulators and policymakers can take to encourage the development of this integrated green urban grid

An Integrated Green Urban Electrical Grid

This Article will discuss the vision of a new green urban grid that relies on decentralized generation and storage, energy efficiency, and demand response. Much of the literature focuses on the development of aspects of the green grid, such as energy efficiency, without consideration of how these resources should be integrated to effectively reduce greenhouse gas emissions and pollution, maintain reliability, and create economic opportunity. After discussing the components of the green urban grid, this Article will discuss why integrating these components is essential to meeting renewable policy goals, and finally, this Article will discuss steps that regulators and policymakers can take to encourage the development of this integrated green urban grid

Self adapting smart electrical grid

Title from PDF of title page, viewed on July 30, 2014Thesis advisor: Vijay KumarVitaIncludes bibliographical references (pages 55-56)Thesis (M. S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2014Following the invention of electricity the electrical grid system was one of the biggest achievements of the twentieth century. It has been responsible for delivering power to millions of homes and businesses. As the demand for power increases due to the continued modernization of our society the strain on the current power grid is increasing at a steady pace. Since 1982 the demand for electricity has surpassed transmission growth by 25% each year, in essence we are using up more resource then we are generating, [15]. This has led to the system showing signs of weakness in the form of Blackouts. There have been 5 blackouts in the past 40 years out of which 3 of them have occurred in the last 9 years, [15]. At the same time requirements of more environmentally friendly power sources is supplying additional engineering challenges. Case in point, the population of US just accounts for 4% of the world's population but it is responsible for generating 25% of the greenhouse gasses that are currently emitted with the electrical grid system being one of the biggest contributors. In its present state the electrical grid system is also highly inefficient and wastes precious natural resources used to generate this power. If only the grid efficiency is increased by 5% that would be equivalent to removing greenhouse gas emission from 53 million cars, [15]. Ultimately the thing that directly affects consumers is the dollar amount that they pay for this electricity, which has also doubled over the past couple of decades. The present process that uses a centralized control center to balance the grid seems to be inadequate and ageing at a rapid pace. This way of power delivery is now more than 50 years old, it may have been the best that technology had to offer during that time but in today's world of rapid information exchange and distributed parallel processing its seems antiquated. This thesis proposes a solution that is dependent on a more distributed manner in which the grid can be balanced rather than relying on a single control center. This paper puts forward a communication protocol and a communication algorithm that makes the system self-adapting to changing power demands in real-time. The algorithm is designed to prioritize distribution of power locally hence cutting down on the need to transmit power over long distances while reducing the demands on the remote power generation unitsAbstract -- Illustrations -- List of abbreviations -- Acknowledgements - Introductions -- Research Problems -- Solution and Scheme -- Simulation and results -- Future Enhancements -- Conclusion -- Bibliograph