41 research outputs found

    A general approach to the planning of a transmission network

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    Ph.D.Atif S. Deb

    Nuclear Magnetohydrodynamic EMP, Solar Storms, and Substorms

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    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

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

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    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

    Breaker to Control Center Integrated Protection, Control and Operations Model

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    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

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    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

    Assessment of transmission system harmonics

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    Issued as final repor

    A MultiPhase Power Flow Model for µGrid Analysis

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    This paper presents a new advanced model of an electric power system with distributed energy sources forming a microgrid (µGrid). The µGrid is a radial or networked low voltage distribution system with distributed sources. Each source is interfaced to the system via converters. The DC bus of the converter may have energy storage capability via large capacitors or batteries. The µGrid load consists of both single and three phase loads resulting in unbalanced operating conditions. The µGrid circuits may be three-wire, four-wire or five-wire. The grounding of the system may be single point or multipoint. The analysis of this system requires a new approach. This paper presents a new method for modeling and analysis of this system. The approach consists of two steps: (a) modeling each component of the system via a set of quadratic equations no matter how complex the nonlinearities of the model are and (b) a Newton’s method for the solution of the overall network equations. The method is extremely efficient and robust. The proposed method can accommodate various control modes of micro-sources. Examples of these controls are given in the paper
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