Structural Vulnerability Analysis of Electric Power Distribution Grids

Power grid outages cause huge economical and societal costs. Disruptions in the power distribution grid are responsible for a significant fraction of electric power unavailability to customers. The impact of extreme weather conditions, continuously increasing demand, and the over-ageing of assets in the grid, deteriorates the safety of electric power delivery in the near future. It is this dependence on electric power that necessitates further research in the power distribution grid security assessment. Thus measures to analyze the robustness characteristics and to identify vulnerabilities as they exist in the grid are of utmost importance. This research investigates exactly those concepts- the vulnerability and robustness of power distribution grids from a topological point of view, and proposes a metric to quantify them with respect to assets in a distribution grid. Real-world data is used to demonstrate the applicability of the proposed metric as a tool to assess the criticality of assets in a distribution grid

TRADEOFF ANALYSIS OF BACKUP POWER GENERATION SOLUTIONS FOR MILITARY BASES

Energy security is becoming increasingly important as the DOD relies on energy to build and project combat power from military installations. Installation energy managers currently ensure uninterrupted power to mission-critical facilities through emergency stand-alone diesel generators. Research has recently indicated that networks of smaller diesel generators offer greater energy security benefits than a network of a few large diesel generators. However, existing research has not compared or analyzed the cost and resilience between the two strategies. This capstone examines the cost and resilience of centralized and decentralized power architectures by developing a general methodology to capture comprehensive life-cycle costs and metrics. It examines resilience for various configurations of networked diesel generators. Installation power managers can apply this method to quantitatively compare life-cycle cost and resilience of emergency diesel generator solutions to improve energy security within the unique constraints of an installation. The capstone then applied this methodology to the aging diesel generator power plant at Naval Station, Rota, Spain, which demonstrated that decentralized architecture was the most cost-effective strategy for resilience. Finally, the capstone presents these findings and general methodology for future application.Navy Shore Energy Technology Transition and Integration (NSETTI), Naval Facilities (NAVFAC) Engineering and Expeditionary Warfare Center (EXWC), Port Hueneme, CA, 93043Captain, United States ArmyMajor, United States ArmyMajor, United States ArmyCaptain, United States ArmyCaptain, United States ArmyApproved for public release. Distribution is unlimited

Review of Systems Engineering (SE) Methods and Their Application to Wave Energy Technology Development

The design of effective and economically viable wave energy devices involves complex decision-making about the product based on conceptual design information, including stakeholder requirements, functions, components and technical parameters. The great diversity of concepts makes it extremely difficult to create fair comparisons of the relative merits of the many different designs. Conventional design approaches have proved insufficient to guarantee wave energy technologies meet their technical and economic goals. Systems engineering can provide a suitable framework to overcome the obstacles towards a successful wave energy technology. The main objective of this work is to review the well-established systems engineering approaches that have been successfully implemented in complex engineering problems and to what extent they have been applied to wave energy technology development. The paper first reviews how system information can be organised in different design domains to guide the synthesis and analysis activities and the definition of requirements and metrics, as well as the search for solutions and decision-making. Then, an exhaustive literature review on the application of systems engineering approaches to wave energy development is presented per design domain. Finally, a set of conclusions is drawn, along with some suggestions for improving the effectiveness of wave energy technology development.Authors would like to thank the Basque Government through the research groups IT1314‐19 and GIU19/276 and the Scottish Government for the support of Wave Energy Scotland

Assessing Resilience in Power Grids as a Particular Case of Supply Chain Management

Electrical power grids represent a critical infrastructure for a nation as well as strategically important. Literature review identified that power grids share basic characteristics with Supply Chain Management. This thesis presents a linear programming model to assess power grid resilience as a particular case of Supply Chain Management. Since resilient behavior is not an individual or specific system\u27s attribute but a holistic phenomenon based on the synergic interaction within complex systems, resilience drivers in power grids were identified. Resilience is a function of Reliability, Recovery Capability, Vulnerability and Pipeline Capacity. In order to embed heterogeneous variables into the model, parameterization of resilience drivers were developed. A principle of improving resilience through redundancy was applied in the model by using a virtual redundancy in each link which allows reliability improvement throughout the entire network. Vulnerability was addressed through the standard MIL-STD 882D, and mitigated through security allocation. A unique index (R) integrates the resilience complexity to facilitate alternate scenarios analysis toward strategic decision making. Decision makers are enabled to improve overall power grid performance through reliability development as well as security allocation at the more strategic links identified by the optimal solutions. Moreover, this tool lets decision makers fix grid variables such as reliability, reduced pipeline capacity, or vulnerabilities within the model in order to find optimal solutions that withstand disruptions. The model constitutes an effective tool not only for efficient reliability improvement but also for rational security allocation in the most critical links within the network. Finally, this work contributes to the federal government mandates accomplishment, intended to address electrical power-related risks and vulnerabilities

Providing Optimal Value to Energy Consumers Through Microgrids

Microgrids are an increasingly popular means of making a smaller, smarter, cleaner, and more resilient energy grid. When Superstorm Sandy hit the northeast states, a few microgrids continued to provide their constituents with energy for weeks while the rest of the grid was down. Microgrids typically involve small-scale energy generation coupled with nearby storage and distribution, and are connected to, but capable of disconnecting from, the macrogrid during a power outage.This Comment will analyze the economics of microgrids, focusing on the necessity of effective cost-benefit analyses. In order to allow for the development of microgrids, regulators should create appropriate mechanisms for microgrid developers to recover the costs of development and operation. However, when incentivizing microgrid development, regulators must remain focused onmaintaining an optimal market for consumers, by accounting for the net utility provided by the microgrid. The benefits and costs of microgrids must be quantified both when planning specific microgrid projects and when creating regulatory frameworks. The efficacy of energy policy relative to microgrids will turn on the accuracy of the cost-benefit analysis used by regulators and developers. This Comment will begin by introducing what microgrids are, their costs, benefits, barriers, the driving forces behind their development, and some notable microgrid success stories. Part I will describe the present uncertainty around microgrid regulation and discuss the need to introduce specific microgrid legislation/regulation to increase certainty. Part II will discuss modern attempts to evaluate the costs and benefits of microgrids and the importance of further developing cost-benefit analyses. Part III will address how microgrids fit into typical laws governing public utilities. Part IV will discuss how states should regulate and incentivize microgrid development, with greater or lesser emphasis on market efficiency. This portion will also analyze creative uses of rate-making to intelligently encourage microgrid development. Lastly, Part V will address a means of fitting energy storage, and through it, microgrids, into wholesale markets, thereby adding an important source of cost recovery to microgrid developers

Resilience-driven planning and operation of networked microgrids featuring decentralisation and flexibility

High-impact and low-probability extreme events including both man-made events and natural weather events can cause severe damage to power systems. These events are typically rare but featured in long duration and large scale. Many research efforts have been conducted on the resilience enhancement of modern power systems. In recent years, microgrids (MGs) with distributed energy resources (DERs) including both conventional generation resources and renewable energy sources provide a viable solution for the resilience enhancement of such multi-energy systems during extreme events. More specifically, several islanded MGs after extreme events can be connected with each other as a cluster, which has the advantage of significantly reducing load shedding through energy sharing among them. On the other hand, mobile power sources (MPSs) such as mobile energy storage systems (MESSs), electric vehicles (EVs), and mobile emergency generators (MEGs) have been gradually deployed in current energy systems for resilience enhancement due to their significant advantages on mobility and flexibility. Given such a context, a literature review on resilience-driven planning and operation problems featuring MGs is presented in detail, while research limitations are summarised briefly. Then, this thesis investigates how to develop appropriate planning and operation models for the resilience enhancement of networked MGs via different types of DERs (e.g., MGs, ESSs, EVs, MESSs, etc.). This research is conducted in the following application scenarios: 1. This thesis proposes novel operation strategies for hybrid AC/DC MGs and networked MGs towards resilience enhancement. Three modelling approaches including centralised control, hierarchical control, and distributed control have been applied to formulate the proposed operation problems. A detailed non-linear AC OPF algorithm is employed to model each MG capturing all the network and technical constraints relating to stability properties (e.g., voltage limits, active and reactive power flow limits, and power losses), while uncertainties associated with renewable energy sources and load profiles are incorporated into the proposed models via stochastic programming. Impacts of limited generation resources, load distinction intro critical and non-critical, and severe contingencies (e.g., multiple line outages) are appropriately captured to mimic a realistic scenario. 2. This thesis introduces MPSs (e.g., EVs and MESSs) into the suggested networked MGs against the severe contingencies caused by extreme events. Specifically, time-coupled routing and scheduling characteristics of MPSs inside each MG are modelled to reduce load shedding when large damage is caused to each MG during extreme events. Both transportation networks and power networks are considered in the proposed models, while transporting time of MPSs between different transportation nodes is also appropriately captured. 3. This thesis focuses on developing realistic planning models for the optimal sizing problem of networked MGs capturing a trade-off between resilience and cost, while both internal uncertainties and external contingencies are considered in the suggested three-level planning model. Additionally, a resilience-driven planning model is developed to solve the coupled optimal sizing and pre-positioning problem of MESSs in the context of decentralised networked MGs. Internal uncertainties are captured in the model via stochastic programming, while external contingencies are included through the three-level structure. 4. This thesis investigates the application of artificial intelligence techniques to power system operations. Specifically, a model-free multi-agent reinforcement learning (MARL) approach is proposed for the coordinated routing and scheduling problem of multiple MESSs towards resilience enhancement. The parameterized double deep Q-network method (P-DDQN) is employed to capture a hybrid policy including both discrete and continuous actions. A coupled power-transportation network featuring a linearised AC OPF algorithm is realised as the environment, while uncertainties associated with renewable energy sources, load profiles, line outages, and traffic volumes are incorporated into the proposed data-driven approach through the learning procedure.Open Acces

JRC Ocean Energy Status Report: 2016 Edition

Assessment of the Ocean Energy status in 2016 This report presents the current status of major ocean energy technologies, focusing primarily on tidal stream and wave energy. Europe is the global leader in the development of ocean energy technologies, hosting most of global developers. Overall, sector is progressing towards the deployment of demonstration farms, and the policy scenario in the EU is helping shaping the industryJRC.C.7-Knowledge for the Energy Unio

Optimal placement of fuses and switches in active distribution networks using value-based MINLP

Contingency conditions in distribution networks create financial losses for different parts of the system including electricity customers, electricity retailers, distributed generation (DG) units, etc. Therefore, protective device allocation methods have been introduced in recent years to enhance the reliability of the power system. In this study, a new formulation is proposed to find the optimal places of sectionalizing switches and fuses while taking the financial loss of both electricity customers and DG units into account. The current method has the flexibility to consider DG effect on any location of the network and its islanded operation in case of contingencies. Moreover, the uncertainty in load and renewable generation is taken into account using stochastic programming. The results demonstrate that the DG units and their financial loss can change the results of switch and fuse placement dramatically when there are no tie switches in the network. Furthermore, it is found that this method can decrease the total reliability costs by 3.86% when high penetration of DG units is introduced into a modified Roy Billinton test system (RBTS). The problem is modeled as a mixed-integer nonlinear (MINLP) formulation and is handled using BARON solver in GAMS environment

Risk Management Decision Making for Security and Trust in Hardware Supply Chains

Modern cyber-physical systems are enabled by electronic hardware and embedded systems. The security of these sub-components is a concern during the design and operational phases of cyber-physical system life cycles. Compromised electronics can result in mission-critical failures, unauthorized access, and other severe consequences. As systems become more complex and feature greater connectivity, system owners must make decisions regarding how to mitigate risks and ensure resilience and trust. This paper provides an overview of research efforts related to assessing and managing risks, resilience, and trust with an emphasis on electronic hardware and embedded systems. The research takes a decision-oriented perspective, drawing from the perspectives of scenario planning and portfolio analysis, and describes examples related to the risk-based prioritization of cyber assets in large-scale systems