Joint Planning of Natural Gas and Electric Power Transmission with Spatially Correlated Failures

We develop and illustrate a method for the joint planning of natural gas and electric power systems that are subject to spatially correlated failures of the kind that would be expected to occur in the case of extreme weather events. Our approach utilizes a two-stage stochastic planning and operations framework for a jointly planned and operated gas and electric power transmission system. Computational tractability is achieved through convex relaxations of the natural gas flow equations and the use of a machine learning algorithm to reduce the set of possible contingencies. We illustrate the method using a small test system used previously in the literature to evaluate computational performance of joint gas-grid models. We find that planning for geographically correlated failures rather than just random failures reduces the level of unserved energy relative to planning for random (spatially uncorrelated failures). Planning for geographically correlated failures, however, does not eliminate the susceptability of the joint gas-grid system to spatially uncorrelated failures

Quantification and mitigation of the impacts of extreme weather on power system resilience and reliability

Modelling the impact of extreme weather on power systems is a computationally expensive, challenging area of study due to the diversity of threats, complicatedness of modelling, and data and simulation requirements to perform the relevant studies. The impacts of extreme weather – specifically wind – are considered. Factors such as the distribution of outage probability on lines and the potential correlation with wind power generation during storms are investigated; so too is sensitivity of security assessments involving extreme wind to the relationships used between failures and the natural hazard being studied, specifically wind speed. A large scale simulation ensemble is developed and demonstrated to investigate what are deemed the most significant features of power system simulation during extreme weather events. The challenges associated with modelling high impact low probability (HILP) events are studied and demonstrate that the results of security assessments are significantly affected by the granularity of incident weather data being used and the corrections or interpolation being applied to the source data. A generalizable simulation framework is formulated and deployed to investigate the significance of the relationship between incident natural hazards, in this case wind, and its corresponding impact on system resilience. Based on this, a large-scale simulation model is developed and demonstrated to take consideration of a wide variety of factors which can affect power systems during extreme weather events including, but not limited to, under frequency load shedding, line overloads, and high wind speed shutdown and its impact on wind generation. A methodology for quantifying and visualising distributed overhead line failure risk is also demonstrated in tandem with straightforward methods for making wind power projections over transmission systems for security studies. The potential correlation between overhead line risk and wind power generation risk is illustrated visually on representations of GB power networks based on real world data.Open Acces

Quantitative dependability and interdependency models for large-scale cyber-physical systems

Cyber-physical systems link cyber infrastructure with physical processes through an integrated network of physical components, sensors, actuators, and computers that are interconnected by communication links. Modern critical infrastructures such as smart grids, intelligent water distribution networks, and intelligent transportation systems are prominent examples of cyber-physical systems. Developed countries are entirely reliant on these critical infrastructures, hence the need for rigorous assessment of the trustworthiness of these systems. The objective of this research is quantitative modeling of dependability attributes -- including reliability and survivability -- of cyber-physical systems, with domain-specific case studies on smart grids and intelligent water distribution networks. To this end, we make the following research contributions: i) quantifying, in terms of loss of reliability and survivability, the effect of introducing computing and communication technologies; and ii) identifying and quantifying interdependencies in cyber-physical systems and investigating their effect on fault propagation paths and degradation of dependability attributes. Our proposed approach relies on observation of system behavior in response to disruptive events. We utilize a Markovian technique to formalize a unified reliability model. For survivability evaluation, we capture temporal changes to a service index chosen to represent the extent of functionality retained. In modeling of interdependency, we apply correlation and causation analyses to identify links and use graph-theoretical metrics for quantifying them. The metrics and models we propose can be instrumental in guiding investments in fortification of and failure mitigation for critical infrastructures. To verify the success of our proposed approach in meeting these goals, we introduce a failure prediction tool capable of identifying system components that are prone to failure as a result of a specific disruptive event. Our prediction tool can enable timely preventative actions and mitigate the consequences of accidental failures and malicious attacks --Abstract, page iii

Flexibility Ranking of Water Distribution System Designs Under Future Mechanical and Hydraulic Uncertainty

AbstractAnnually a large amount of money should be spent by water authorities to adapt and update water distribution systems (WDSs)to the latest client's needs and variations known as adaptation cost. To prevent or lessen WDSs’ adaptation cost it is essential to insert a level of flexibility into WDS layouts from the very beginning in planning or designing stages [1]. This study proposed a simple technique based on multi-criteria decision analysis to rank a set of WDS layouts based on their level of flexibility under future mechanical and hydraulic uncertainty

Learning the Evolution of Correlated Stochastic Power System Dynamics

A machine learning technique is proposed for quantifying uncertainty in power system dynamics with spatiotemporally correlated stochastic forcing. We learn one-dimensional linear partial differential equations for the probability density functions of real-valued quantities of interest. The method is suitable for high-dimensional systems and helps to alleviate the curse of dimensionality.Comment: 5 pages, 2 figures, Accepted to 2022 IEEE PES G