Cascading blackout overall structure and some implications for sampling and mitigation

Cascading blackouts can be thought of as initiating events followed by propagating events that progressively weaken the power system. We briefly discuss the implications for assessing cascading risk by proper sampling from the various sources of uncertainty and for mitigating cascading risk by reducing both the initiating events and their propagation

Emergency Decision Making and Disaster Recovery

There is growing evidence that the number and severity of natural disasters and their cascading events such as power blackouts are increasing. These extreme events threaten human lives, displace hundreds of thousands of people and cause huge financial losses. Therefore, it is important to understand better how socio-economic systems can best respond to these disasters and how they can recover quickly, build back better and become more resilient. This thesis comprises five separate studies of four different types of disasters. The overall objective is to improve the understanding of how society copes with and makes decisions in crisis and emergency situations, and how disaster affected areas recover, particularly in terms of speed and quality. This is a huge subject and rather than focusing on just one event or a single type of disaster, the objective is to look at different types of disaster events by studying people’s risk perception and their (real or expected) disaster behaviour in the context of different phases of the disaster cycle from immediate response to longer-term recovery and resilience building. The five studies featured in this thesis are: 1. Behaviour during a long-lasting blackout in France and Germany, investigated through role-playing scenario exercises to study how society would cope. The aim is provide information to emergency managers and policy makers about community needs and people’s likely behaviour in future blackouts, 2. Analyses of people’s preparedness, perception and behaviour during floods in the UK and Germany and their attitude to public authorities, investigated through face-to-face interview surveys with people living and working in the flood prone areas, 3. Analyses of flood evacuation compliance, from both decision-theoretic and game-theoretic perspectives, using the Warning Compliance Model, which incorporates a Bayesian information system that formalizes the statistical effects of a warning forecast based on the harmonious structure of a Hidden Markov Model, 4. Examining recovery after two major comparable floods in UK and Germany in terms of the impacts, levels of preparedness and government response, investigated with face-to-face interview surveys with residents and businesses and online surveys with experts, 5. Tourist destination recovery in the Philippines after earthquake and typhoon, investigated through interviews with tourist managers and stakeholders. The key areas for future research revolve around identifying in more detail and with greater precision those factors that predispose a society to respond effectively to a disaster, to recover as quickly as possible and to build resilience in order to better confront future disasters

Mission Analysis and Design of MECSE Nanosatellite

Since the moment humankind started venturing into the realms of space, the problems associated with Radio Frequency (RF) blackout period due to plasma sheath interactions with the spacecraft have been an unsolved issue. During this period, the spacecraft loses all the communication with the control center or satellite including voice, real-time data telemetry and GNSS navigation. Considering that continuous communication during atmospheric re-entry is crucial to ensure safety and accomplishment of manned and unmanned space missions, solutions for the mitigation of RF blackout are of high priority and a requirement for the design of future space vehicles. One solution is the use of an electromagnetic field to manipulate the plasma layer surrounding the vehicle. In this M.Sc. thesis, an innovative CubeSat mission for the manipulation of ionospheric plasma is proposed and designed. MECSE (Magneto/Electro hydrodynamics CubeSat Experiment) aims to confirm in space that the electron density of the plasma layer can be reduced through the generation of an electromagnetic field. From a systems engineering perspective, the early phases of MECSE mission are fully designed (phases 0, A and B1 of ESA’s project lifecycle). Starting with mission characterization, the scientific case is presented and the feasibility of the mission is studied based on tradespace exploration methods. Then, the mission objectives, requirements and figures of merit are defined. The mission analysis is performed considering a reference orbit from a launch survey. In the end, a preliminary design of the spacecraft is presented including the analyses performed for the subsystems, the concept of operations and the definition of system requirements. This M.Sc. thesis also focusses on the study of orbital lifetime predictions for a CubeSat. The impact of using different solar and geomagnetic activity models proposed by standard guidelines is investigated using STK and DRAMA software and compared against historical data from already decayed CubeSats. It is concluded that there are still large deviations between the results provided by different models and that the satellite parameters recommended by the guidelines are not suitable when predicting accurately the orbital lifetime of a CubeSat. The orbital lifetime of MECSE nanosatellite is predicted and the effects of variations in orbital and satellite parameters are evaluated.Desde o começo da aventura da humanidade no espaço que os problemas associados ao período de blackout de comunicações são uma questão por resolver. Durante este período, o veículo espacial perde toda a comunicação com o centro de controlo ou satélite, incluindo voz, dados de telemetria em tempo real e navegação GNSS. Uma vez que a comunicação contínua é um fator crítico para garantir a segurança e o sucesso de missões espaciais tripuladas e não tripuladas, torna-se essencial encontrar soluções para a mitigação do blackout de comunicações. De facto, estas soluções são de extrema importância e já consideradas um requisito no desenvolvimento de futuros veículos espaciais. Uma solução é a utilização de um campo eletromagnético para manipular a camada de plasma que se forma em volta do veículo. Nesta tese de mestrado, uma inovadora missão CubeSat para a manipulação do plasma ionosférico é proposta e projetada. MECSE (Experimento de Magneto/Electro hidrodinâmica em Cubesat) tem o objetivo de provar no espaço que a densidade eletrónica da camada de plasma pode ser reduzida através da geração de um campo eletromagnético. De uma perspetiva de engenharia de sistemas, as fases inicias da missão MECSE são projetadas (fases 0, A e B1 do ciclo de vida da ESA). Começando por uma caracterização da missão, o caso científico é apresentado e a viabilidade da missão é estudada com base em métodos de exploração científica e tecnológica. De seguida, os objetivos de missão, requisitos e figuras de mérito são definidos. A análise de missão é feita considerando uma órbita referência baseada em pesquisa de lançamentos. No fim, um design preliminar do satélite é apresentado incluindo as análises realizadas para os subsistemas, o conceito de operações e a definição dos requisitos de sistema. Esta tese de mestrado foca-se ainda em estudar a previsão do tempo de vida orbital de um CubeSat. O impacto de usar diferentes modelos recomendados pelas diretrizes standard para a atividade solar e geomagnética é investigado usando STK e DRAMA softwares e comparado com dados históricos de CubeSats que já reentraram. É concluído que ainda existem enormes variações nos resultados de diferentes modelos e que os parâmetros de satélite recomendados pelas directrizes não são adequados para prever o tempo de vida orbital com precisão. O tempo de vida do satélite MECSE é previsto e os efeitos de variações em parâmetros orbitais e de satélite são avaliados

Modeling, Simulation, and Analysis of Cascading Outages in Power Systems

Interconnected power systems are prone to cascading outages leading to large-area blackouts. Modeling, simulation, analysis, and mitigation of cascading outages are still challenges for power system operators and planners.Firstly, the interaction model and interaction graph proposed by [27] are demonstrated on a realistic Northeastern Power Coordinating Council (NPCC) power system, identifying key links and components that contribute most to the propagation of cascading outages. Then a multi-layer interaction graph for analysis and mitigation of cascading outages is proposed. It provides a practical, comprehensive framework for prediction of outage propagation and decision making on mitigation strategies. It has multiple layers to respectively identify key links and components, which contribute the most to outage propagation. Based on the multi-layer interaction graph, effective mitigation strategies can be further developed. A three-layer interaction graph is constructed and demonstrated on the NPCC power system.Secondly, this thesis proposes a novel steady-state approach for simulating cascading outages. The approach employs a power flow-based model that considers static power-frequency characteristics of both generators and loads. Thus, the system frequency deviation can be calculated under cascading outages and control actions such as under-frequency load shedding can be simulated. Further, a new AC optimal power flow model considering frequency deviation (AC-OPFf) is proposed to simulate remedial control against system collapse. Case studies on the two-area, IEEE 39-bus, and NPCC power systems show that the proposed approach can more accurately capture the propagation of cascading outages when compared with a conventional approach using the conventional power flow and AC optimal power flow models.Thirdly, in order to reduce the potential risk caused by cascading outages, an online strategy of critical component-based active islanding is proposed. It is performed when any component belonging to a predefined set of critical components is involved in the propagation path. The set of critical components whose fail can cause large risk are identified based on the interaction graph. Test results on the NPCC power system show that the cascading outage risk can be reduced significantly by performing the proposed active islanding when compared with the risk of other scenarios without active islanding

The Internalization of Externalities in The Production of Electricity: Willingness to Pay for the Attributes of a Policy for Renewable Energy

This paper investigates the willingness to pay of a sample of residents of Bath, England, for a hypothetical program that promotes the production of renewable energy. Using choice experiments, we assess the preferences of respondents for a policy for the promotion of renewable energy that (i) contributes to the internalization of the external costs caused by fossil fuel technologies; (ii) affects the security of energy supply; (iii) has an impact on the employment in the energy sector; (iv) and leads to an increase in the electricity bill. Responses to the choice questions show that our respondents are in favour of a policy for renewable energy and that they attach a high value to a policy that brings private and public benefits in terms of climate change and energy security benefits. Our results therefore suggest that consumers are willing to pay a higher price for electricity in order to internalize the external costs in terms of energy security, climate change and air pollution caused by the production of electricity.Non Market Valuation, Choice Experiments, Willingness to Pay, Renewable Energy, Energy Security, Greenhouse Gases Emissions

Exploring cascading outages and weather via processing historic data

We describe some bulk statistics of historical initial line outages and the implications for forming contingency lists and understanding which initial outages are likely to lead to further cascading. We use historical outage data to estimate the effect of weather on cascading via cause codes and via NOAA storm data. Bad weather significantly increases outage rates and interacts with cascading effects, and should be accounted for in cascading models and simulations. We suggest how weather effects can be incorporated into the OPA cascading simulation and validated. There are very good prospects for improving data processing and models for the bulk statistics of historical outage data so that cascading can be better understood and quantified

A Critical Review of Robustness in Power Grids using Complex Networks Concepts

Complex network theory for analyzing robustness in energy gridsThis paper reviews the most relevant works that have investigated robustness in power grids using Complex Networks (CN) concepts. In this broad field there are two different approaches. The first one is based solely on topological concepts, and uses metrics such as mean path length, clustering coefficient, efficiency and betweenness centrality, among many others. The second, hybrid approach consists of introducing (into the CN framework) some concepts from Electrical Engineering (EE) in the effort of enhancing the topological approach, and uses novel, more efficient electrical metrics such as electrical betweenness, net-ability, and others. There is however a controversy about whether these approaches are able to provide insights into all aspects of real power grids. The CN community argues that the topological approach does not aim to focus on the detailed operation, but to discover the unexpected emergence of collective behavior, while part of the EE community asserts that this leads to an excessive simplification. Beyond this open debate it seems to be no predominant structure (scale-free, small-world) in high-voltage transmission power grids, the vast majority of power grids studied so far. Most of them have in common that they are vulnerable to targeted attacks on the most connected nodes and robust to random failure. In this respect there are only a few works that propose strategies to improve robustness such as intentional islanding, restricted link addition, microgrids and smart grids, for which novel studies suggest that small-world networks seem to be the best topology.This work has been partially supported by the project TIN2014-54583-C2-2-R from the Spanish Ministerial Commission of Science and Technology (MICYT), by the project S2013/ICE-2933 from Comunidad de Madrid and by the project FUTURE GRIDS-2020 from the Basque Government