Nuclear Magnetohydrodynamic EMP, Solar Storms, and Substorms

In addition to a fast electromagnetic pulse (EMP), a high altitude nuclear burst produces a relatively slow magnetohydrodynarnic EMP (MHD EMP), whose effects are like those from solar storm geomagnetically induced currents (SS GIC). The MHD EMP electric field E < 10^-1 V/m and lasts < 10^2 sec, whereas for solar storms E > 10^-2 V/m and lasts >10^3 sec. Although the solar storm electric field is lower than MHD EMP, the solar storm effects are generally greater due to their much longer duration. Substorms produce much smaller effects than SS GIC, but occur much more frequently. This paper describes the physics of such geomagnetic disturbances and analyzes their effects.Comment: 29 pages, 14 figures, 5 table

A general approach to the planning of a transmission network

Ph.D.Atif S. Deb

Optimal Reactive Power Dispatch Formulated as Quadratic OPF and Solved via CS-SLP

Increased penetration of inverter interfaced renewable energy resources creates challenges and opportunities for reactive power management in the modern electricity grid. Because of the multiplicity of new resources, new computational tools and optimization models are needed in formulating and solving the Optimal Reactive Power Dispatch Problem (ORPD). In this paper, we propose (1) an object-oriented ORPD formulation based on high-fidelity modeling of each device in the network, especially those with VAR/V control capability and (2) a two-step Convex Solution-Sequential Linear Programming algorithm. The proposed method introduces two innovations: (a) high fidelity quadratized models of each component of the power system with emphasis on those components that have VAR/V control capability; and (b) an object oriented convexification of the resulting quadratic OPF problem; the solution is obtained by first solving the convex problem using public solvers for convex problems and them removing the relaxation and solving the original OPF using SLP, starting from the solution of the relaxed (convex) problem

Integrated Centralized Substation Protection

Substation cyber assets are mission critical for protection and control of substations. Managing and ensuring their secure operation is of paramount importance. A known vulnerability is hidden failures which are responsible for about 10% of mis-operations and their detrimental effects on system reliability. The paper presents an integrated centralized substation protection approach that is based on the recently developed setting-less relays which are integrated into a centralized substation protection scheme with the following features: (a) fast, dependable and secure protection of each substation protection zone by a settingless relay, (b) supervision of each settingless relay by validating relay input data by a substation wide state estimator, (c) self-healing against hidden failures by detecting and identifying compromised data and replacing them with estimated values, thus ensuring that the settingless relays will always operate on validated data. The paper provides a summary review of the settingless protective relay and introduces the Integrated Centralized Substation Protection Scheme (ICSP) which uses the data from all settingless relays in the substation to perform a substation wide state estimation. The state estimator uses a hypothesis testing algorithm to determine whether (a) data are valid with no faults or hidden failures, (b) data are valid and a fault exists in the system, or (c) some data are invalid due to hidden failures. In the last case, the state estimator uses the substation state and model to replace the compromised data with estimated values and thus enabling self-immunization against hidden failures. A byproduct of the method is the substation state estimate which is transmitted to the control center where it is used with the state from all substations to synthesize the system wide state estimate and model. Architectural issues are addressed as well as migration issues of existing systems into the proposed ICSP

Breaker to Control Center Integrated Protection, Control and Operations Model

Technological advances in electric energy system data acquisition systems, time synchronization, and cyber assets used in power system substations, distribution systems, and control centers offer new opportunities to dramatically improve the practice of monitoring, protection, control, and operation of the system. We can make the computer based new technologies smarter and more intelligent to fully automate the basic protection and control functions. The challenges posed to the system from the continuous deployment of renewable resources that are typically inverter interface resources require monitoring of the system at much higher rates and development of protection and control systems that can respond in much faster rates than for conventional systems and they are immune to the characteristics of the new system, namely reduced fault currents and suppressed negative and zero sequence components of the fault currents. We propose a new system that provides validated data at fast rates (once per cycle), protective relays that are immune to the effects of inverter interfaced generation, detect anomalies, and enable the continuous operation of relays and other functions even in the presence of hidden failures in instrumentation. This system will be able to enable the operators to meet the challenges posed by the evolving power system and provides robust solutions to the new requirements

Advanced extended-term simulation approach with flexible quasisteady-state and dynamic semi-analytical simulation engines

Power system simulations that extend over a time period of minutes, hours, or even longer are called extended-term simulations. As power systems evolve into complex systems with increasing interdependencies and richer dynamic behaviors across a wide range of timescales, extended-term simulation is needed for many power system analysis tasks (e.g., resilience analysis, renewable energy integration, cascading failures), and there is an urgent need for efficient and robust extended-term simulation approaches. The conventional approaches are insufficient for dealing with the extended-term simulation of multi-timescale processes. This paper proposes an extended-term simulation approach based on the semi-analytical simulation (SAS) methodology. Its accuracy and computational efficiency are backed by SAS's high accuracy in event-driven simulation, larger and adaptive time steps, and flexible switching between full-dynamic and quasi-steady-state (QSS) models. We used this proposed extended-term simulation approach to evaluate bulk power system restoration plans, and it demonstrates satisfactory accuracy and efficiency in this complex simulation task

Detection of Antibodies against Turkey Astrovirus in Humans

Astroviruses are a leading cause of gastroenteritis in mammals and birds worldwide. Although historically thought to be species-specific, increasing evidence suggests that astroviruses may cross species barriers. In this report, we used enzyme-linked immunosorbent assays to screen sera from three distinct human cohorts involved in influenza studies in Memphis, TN or Chapel Hill, NC, and Midwestern poultry abattoir workers for antibodies to turkey astrovirus type 2 (TAstV-2). Surprisingly, 26% of one cohort’s population was TAstV-2 positive as compared to 0 and 8.9% in the other cohorts. This cohort was composed of people with exposure to turkeys in the Midwestern United States including abattoir workers, turkey growers, and non-occupationally exposed participants. The odds of testing positive for antibodies against turkey astrovirus among abattoir workers were approximately 3 times higher than the other groups. These studies suggest that people with contact to turkeys can develop serological responses to turkey astrovirus. Further work is needed to determine if these exposures result in virus replication and/or clinical disease

Power system dynamic state estimation: motivations, definitions, methodologies, and future work

This paper summarizes the technical activities of the Task Force on Power System Dynamic State and Parameter Estimation. This Task Force was established by the IEEE Working Group on State Estimation Algorithms to investigate the added benefits of dynamic state and parameter estimation for the enhancement of the reliability, security, and resilience of electric power systems. The motivations and engineering values of dynamic state estimation (DSE) are discussed in detail. Then, a set of potential applications that will rely on DSE is presented and discussed. Furthermore, a unified framework is proposed to clarify the important concepts related to DSE, forecasting-aided state estimation, tracking state estimation, and static state estimation. An overview of the current progress in DSE and dynamic parameter estimation is provided. The paper also provides future research needs and directions for the power engineering community

MicroRNA Regulation of Human Protease Genes Essential for Influenza Virus Replication

Influenza A virus causes seasonal epidemics and periodic pandemics threatening the health of millions of people each year. Vaccination is an effective strategy for reducing morbidity and mortality, and in the absence of drug resistance, the efficacy of chemoprophylaxis is comparable to that of vaccines. However, the rapid emergence of drug resistance has emphasized the need for new drug targets. Knowledge of the host cell components required for influenza replication has been an area targeted for disease intervention. In this study, the human protease genes required for influenza virus replication were determined and validated using RNA interference approaches. The genes validated as critical for influenza virus replication were ADAMTS7, CPE, DPP3, MST1, and PRSS12, and pathway analysis showed these genes were in global host cell pathways governing inflammation (NF-κB), cAMP/calcium signaling (CRE/CREB), and apoptosis. Analyses of host microRNAs predicted to govern expression of these genes showed that eight miRNAs regulated gene expression during virus replication. These findings identify unique host genes and microRNAs important for influenza replication providing potential new targets for disease intervention strategies