A Swing-Contract Market Design for Flexible Service Provision in Electric Power Systems

The need for flexible service provision in electric power systems has dramatically increased due to the growing penetration of variable energy resources, as has the need to ensure fair access and compensation for this provision. A swing contract (SC) facilitates flexible service provision because it permits multiple service attributes to be offered together in bundled form with each attribute expressed as a range of possible values rather than as a single point value. This paper discusses a new SC Market Design for electric power systems that permits SCs to be offered by any dispatchable resource. An analytical optimization formulation is developed for the clearing of an SC day-ahead market that can be implemented using any standard mixed integer linear programming (MILP) solver. The practical feasibility of the optimization formulation is demonstrated by means of a numerical example

Impact of Intermediate Hyperglycemia and Diabetes on Immune Dysfunction in Tuberculosis

Supplementary Data: Supplementary materials are available at Clinical Infectious Diseases online at https://academic.oup.com/cid/article/72/1/69/5857148#274319223 . Consisting of data provided by the authors to benefit the reader, the posted materials are not copyedited and are the sole responsibility of the authors, so questions or comments should be addressed to the corresponding author.Copyright © The Author(s) 2020. Background: People with diabetes have an increased risk of developing active tuberculosis (TB) and are more likely to have poor TB-treatment outcomes, which may impact on control of TB as the prevalence of diabetes is increasing worldwide. Blood transcriptomes are altered in patients with active TB relative to healthy individuals. The effects of diabetes and intermediate hyperglycemia (IH) on this transcriptomic signature were investigated to enhance understanding of immunological susceptibility in diabetes-TB comorbidity. Methods: Whole blood samples were collected from active TB patients with diabetes (glycated hemoglobin [HbA1c] ≥6.5%) or IH (HbA1c = 5.7% to <6.5%), TB-only patients, and healthy controls in 4 countries: South Africa, Romania, Indonesia, and Peru. Differential blood gene expression was determined by RNA-seq (n = 249). Results: Diabetes increased the magnitude of gene expression change in the host transcriptome in TB, notably showing an increase in genes associated with innate inflammatory and decrease in adaptive immune responses. Strikingly, patients with IH and TB exhibited blood transcriptomes much more similar to patients with diabetes-TB than to patients with only TB. Both diabetes-TB and IH-TB patients had a decreased type I interferon response relative to TB-only patients. Conclusions: Comorbidity in individuals with both TB and diabetes is associated with altered transcriptomes, with an expected enhanced inflammation in the presence of both conditions, but also reduced type I interferon responses in comorbid patients, suggesting an unexpected uncoupling of the TB transcriptome phenotype. These immunological dysfunctions are also present in individuals with IH, showing that altered immunity to TB may also be present in this group. The TB disease outcomes in individuals with IH diagnosed with TB should be investigated further.European Union’s Seventh Framework Programme (FP7 2007-2013 - Health) under grant agreement No 305279

State-of-the-art, challenges, and future trends in security constrained optimal power flow

This paper addresses the main challenges to the security constrained optimal power flow (SCOPF) computations. We first discuss the issues related to the SCOPF problem formulation such as the use of a limited number of corrective actions in the post-contingency states and the modeling of voltage and transient stability constraints. Then we deal with the challenges to the techniques for solving the SCOPF, focusing mainly on: approaches to reduce the size of the problem by either efficiently identifying the binding contingencies and including only these contingencies in the SCOPF or by using approximate models for the post-contingency states, and the handling of discrete variables. We finally address the current trend of extending the SCOPF formulation to take into account the increasing levels of uncertainty in the operation planning. For each such topic we provide a review of the state of the art, we identify the advances that are needed, and we indicate ways to bridge the gap between the current state of the art and these needs.FP7-EU PEGAS

Power system transient stability preventive and emergency control

A general approach to real-time transient stability control is described, yielding various complementary techniques: pure preventive, open loop emergency, and closed loop emergency controls. Recent progress in terms of a global transient stability constrained optimal power flow are presented, yielding in a scalable nonlinear programming formulation which allows to take near-optimal decisions for preventive control with a computing budget corresponding only to a few runs of standard optimal power flow and time domain simulations. These complementary techniques meet the stringent conditions imposed by the real-life applications

Cost versus life cycle assessment-based environmental impact optimization of drinking water production plants

Empowering decision makers with cost-effective solutions for reducing industrial processes environmental burden, at both design and operation stages, is nowadays a major worldwide concern. The paper addresses this issue for the sector of drinking water production plants (DWPPs), seeking for optimal solutions trading-off operation cost and life cycle assessment (LCA)-based environmental impact while satisfying outlet water quality criteria. This leads to a challenging bi-objective constrained optimization problem, which relies on a computationally expensive intricate process-modelling simulator of the DWPP and has to be solved with limited computational budget. Since mathematical programming methods are unusable in this case, the paper examines the performances in tackling these challenges of six off-the-shelf state-of-the-art global meta-heuristic optimization algorithms, suitable for such simulation-based optimization, namely Strength Pareto Evolutionary Algorithm (SPEA2), Non-dominated Sorting Genetic Algorithm (NSGA-II), Indicator-based Evolutionary Algorithm (IBEA), Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D), Differential Evolution (DE), and Particle Swarm Optimization (PSO). The results of optimization reveal that good reduction in both operating cost and environmental impact of the DWPP can be obtained. Furthermore, NSGA-II outperforms the other competing algorithms while MOEA/D and DE perform unexpectedly poorly

Agent-Based Security Constrained Optimal Power Flow with Primary Frequency Control

International audienceWe propose in this paper a distributed method to solve the security constrained optimal power flow problem (SCOPF) that considers not only contingencies on transmission lines but also on generators.With this aim, we extend the formulation of the SCOPF problem to consider the primary frequency response of generators as well as the short term constraints of generators and transmission lines. Then, we distribute the problem among different agents and we use a decentralized decision making algorithm, based on the Alternating Direction Method of Multipliers (ADMM), to optimize the grid power supply while being resilient to violations that would occur during contingencies. Finally, we prove the effectiveness of this formulation and implementation on a simple test system