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A shipboard power system (SPS) should be stable and reliable in order to ensure that the ship has better fight-through capability and increased fault invulnerability. The protection system is designed to minimize the effects of faults in the SPS, which presents challenges, such as increased fault vulnerability and lack of an electrical ground in the system. If protection devices are not updated after power system reconfiguration, they may not protect the power system appropriately. Therefore the development of elaborate digital protection devices for the SPS is required. This thesis focuses on the model-based methodology for designing a protection scheme for SPS based on instantaneous overcurrent digital relays. To achieve this, an instantaneous overcurrent relay model is first developed in MATLAB/Simulink. Then, the Simulink model is downloaded to the DSP-based platform dSPACE, which runs the Simulink model in real-time, to perform hardware-in-the-loop testing (HIL). Thus, through the dSPACE hardware, the proposed relay model is tested for various fault conditions in three HIL platforms. Different electromagnetic transient real-time digital simulators are used to simulate the SPS, to which protection is provided through the relay modeled in dSPACE. Simulation results from these three HIL platforms demonstrate that the proposed overcurrent relay model was successfully modeled, simulated and tested using various tools for model-based design. Testing results show that the developed model can work with different real-time platforms, and that in contrast to a commercial relay, the developed relay model has increased flexibility because settings such as reclose delay and pickup value can be changed online. This feature can be used to develop an advanced relay model with a dynamic pickup value. An advanced relay model will be useful for the SPS, because such system is subject to topological changes and reconfiguration that are not as prevalent in other types of power systems.

This document explores Hidden Failures in protection systems, which have been identified as key contributors in the degradation of Power System wide-area disturbances. The Hidden Failure Modes in which the protection systems may fail to operate correctly and their consequences are identified in a theoretical approach. This theoretical side has its practical counterpart since a number of Hidden Failure Modes are found in real wide-area disturbances. The original definition of Hidden Failure, which is a failure that remains undetected and is uncovered by another system event, is included as well as developments on Hidden Failure sequence of events and a methodology for Hidden Failure identification. This method is based on Protection Element Functionality Defects (PEFD), which are applicable to all the elements included in the protective chain. PEFD are classified in two main groups. Primary and Back-up protection schemes applied for Generators, Buses, Transformers and Transmission Lines are analyzed. The abnormal Power System conditions that each Power System element may have are enumerated. A catalogue of the relays or relay systems, in charge of detecting and stopping the continuous presence of the abnormal conditions is developed. Relay families organize this catalogue. The relaying schemes for five Special Protection Systems are described. Thirty-three Hidden Failures Modes are included based on the relaying implementation for Primary protection, Back-up protection and Special Protection Systems. These Hidden Failures Modes are based on PEFD-A. Hidden Failures related to PEFD-B are included in a general fashion. Wide-area disturbances based on NERC reports are analyzed and Hidden Failures are identified employing the developed methodology. The mechanisms in the disturbances are summarized and are applicable to Primary protection, Back-up protection and Special Protection Systems. Regions of Vulnerability and Areas of Consequence definitions are included and are identified for a Power System wide-area disturbance. For some protection schemes the term Condition of Vulnerability was developed. Regions of Vulnerability and Areas of Consequence will bring the initial steps towards the problem solution. Further research directions are oriented towards the development of a computer-based tool to track the regions of vulnerability in real time. / Master of Science

Recent major electrical disturbances highlight the extent to which modern societies depend on a reliable power infrastructure and the impact of these undesirable events on the economy and society. Numerous blackout models have been developed in the last decades that capture effectively the cascade mechanism leading to a partial or complete blackout. These models usually consider only the state of the electrical part of the system and investigate how failures or limitations in this system affect the probability and severity of a blackout.However, an analysis of the major disturbances that occurred during the last decade, such as the North America blackout of 2003 and the UCTE system disturbance of 2006, shows that failures or inadequacies in the Information and Communication Technology (ICT) infrastructure and also human errors had a significant impact on most of these blackouts.The aim of this thesis is to evaluate the contribution of these non-electrical events to the risk of power system blackouts. As the nature of these events is probabilistic and not deterministic, different probabilistic techniques have been developed to evaluate their impact on power systems reliability and operation.In particular, a method based on Monte Carlo simulation is proposed to assess the impact of an ICT failure on the operators’ situation awareness and consequently on their performance during an emergency. This thesis also describes a generic framework using Markov modeling for quantifying the impact of insufficient situation awareness on the probability of cascading electrical outages leading to a blackout. A procedure based on Markov modeling and fault tree analysis is also proposed for assessing the impact of ICT failures and human errors on the reliable operation of fast automatic protection actions, which are used to provide protection against fast-spreading electrical incidents. The impact of undesirable interactions and the uncoordinated operation of these protection schemes on power system reliability is also assessed in this thesis.The simulation results of these probabilistic methods show that a deterioration in the state of the ICT infrastructure and human errors affect significantly the probability and severity of power system blackouts. The conclusion of the work undertaken in this research is that failures in all the components of the power system, and not just the “heavy electrical” ones, must be considered when assessing the reliability of the electrical supply.

Aucun cap clair n’a été fixé par les pouvoirs publics européens s’agissant du droit de la protection sociale complémentaire. La contribution du droit européen en la matière est toutefois majeure. Les opérateurs spécialisés chargés de la gestion des régimes institués ont fait l’objet de nombreux textes, quoique non axés spécifiquement sur le droit de la protection sociale complémentaire et ne tenant pas toujours compte de l’originalité du modèle économique et social de certains d’entre eux. Les intérêts des bénéficiaires des dispositifs établis ont été pris en considération davantage en raison de l’extension du rôle du droit du travail au sein de l’Union européenne que des dispositions adoptées en droit de la protection sociale. Située au croisement de plusieurs domaines du droit, de l’économie et de la politique sociale, la protection sociale complémentaire cherche toujours, dans le concert du droit européen, à faire entendre une voix qui lui soit propre. Il est cependant permis d’espérer qu’un fil conducteur soit un jour plus clairement adopté, plaçant l’entreprise, qui constitue le socle du droit de protection sociale complémentaire, au coeur des réflexions et des réformes. C’est en effet au sein des entreprises, et en Europe, qu’est née la protection sociale complémentaire. Il serait cohérent que, deux siècles plus tard, les pouvoirs publics européens reviennent aux origines de celle-ci pour en déterminer l’avenir. / No clear direction has been set by the European authorities regarding complementary social protection law. However, European law still makes a major contribution on the subject. The specialized operators in charge of administrating complementary schemes have been the subject of numerous laws, but not specifically focused on complementary social protection law and not always taking into account the originality of the economic and social model of some of them. The interests of the beneficiaries were more taken into consideration because of the employment law growing position within the European Union than because of the measures adopted on social protection law. Complementary social protection happens to be right at the crossroads of several areas of law, economics and social policy. It is therefore still trying to have its own voice heard in the concert of European law. However, we can hope that a common connecting thread will be more clearly adopted, which will put the company, as the foundation of complementary social protection law, at the heart of debates and reforms. It isindeed within companies, and in Europe, that complementary social protection was born. It would make sense that, two centuries later, European authorities return to the roots of the latter to set a course for the future.