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Improving power flow robustness via circuit simulation methods

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Improving power flow robustness via circuit simulation metho...

IEEE General Meeting Power& Energy Society

作者： Amritanshu Pandey Marko Jereminov Gabriela Hug Larry Pileggi Dept. of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA Power Systems Laboratory ETH Zurich Switzerland

ISBN: (纸本)9781538622131;9781538622124

Recent advances in power system simulation have included the use of complex rectangular current and voltage (I-V) variables for solving the power flow and three-phase power flow problems. This formulation has demonstrated superior convergence properties over conventional polar coordinate based formulations for three-phase power flow, but has failed to replicate the same advantages for power flow in general due to convergence issues with systems containing PV buses. In this paper, we demonstrate how circuit simulation techniques can provide robust convergence for any complex I-V formulation that is derived from our split equivalent circuit representation. Application to power grid test systems with up to 10 4 buses demonstrates consistent global convergence to the correct physical solution from arbitrary initial conditions.

关键词： Load modeling Load flow Integrated circuit modeling Equivalent circuits Convergence Mathematical model Limiting

SWAP: Effective Fine-Grain Management of Shared Last-Level Caches with Minimum Hardware Support

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SWAP: Effective Fine-Grain Management of Shared Last-Level C...

IEEE Symposium on High-Performance computer architecture

作者： Xiaodong Wang Shuang Chen Jeff Setter José F. Martínez Computer Systems Laboratory Cornell University Ithaca NY USA Dept. of Electrical Engineering Stanford University Stanford CA USA

ISBN: (纸本)9781509049868

Performance isolation is an important goal in server-class environments. Partitioning the last-level cache of a chip multiprocessor (CMP) across co-running applications has proven useful in this regard. Two popular approaches are (a) hardware support for way partitioning, or (b) operating system support for set partitioning through page coloring. Unfortunately, neither approach by itself is scalable beyond a handful of cores without incurring in significant performance overheads. We propose SWAP, a scalable and fine-grained cache management technique that seamlessly combines set and way partitioning. By cooperatively managing cache ways and sets, SWAP (“Set and WAy Partitioning”) can successfully provide hundreds of fine-grained cache partitions for the manycore era. SWAP requires no additional hardware beyond way partitioning. In fact, SWAP can be readily implemented in existing commercial servers whose processors do support hardware way partitioning. In this paper, we prototype SWAP on a 48-core Cavium ThunderX platform running Linux, and we show average speedups over no cache partitioning that are twice as large as those attained with ThunderX's hardware way partitioning alone.

关键词： Color Hardware Program processors Probabilistic logic Servers Throughput Interference

Robust convergence of power flow using Tx stepping method with equivalent circuit formulation

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arXiv 2017年

作者： Pandey, Amritanshu Jereminov, Marko Wagner, Martin R. Hug, Gabriela Pileggi, Larry Dept. of Electrical and Computer Engineering Carnegie Mellon University PittsburghPA United States Power Systems Laboratory ETH Zurich Switzerland

Robust solving of critical large power flow cases (with 50k or greater buses) forms the backbone of planning and operation of any large connected power grid. At present, reliable convergence with applications of existing power flow tools to large power systems is contingent upon a good initial guess for the system state. To enable robust convergence for large scale systems starting with an arbitrary initial guess, we extend our equivalent circuit formulation for power flow analysis to include a novel continuation method based on transmission line (‘Tx’) stepping. While various continuation methods have been proposed for use with the traditional ‘PQV’ power flow formulation, these methods have either failed to completely solve the problem or have resulted in convergence to a low voltage solution. The proposed "Tx Stepping" method in this paper demonstrates robust convergence to the high voltage solution from an arbitrary initial guess. Example systems, including 75k+ bus test cases representing different loading and operating conditions for Eastern Interconnection of the U.S. power grid, are solved from arbitrary initial guesses. Copyright © 2017, The Authors. All rights reserved.

关键词： Electric load flow

Improving power flow robustness via circuit simulation methods

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arXiv 2017年

作者： Pandey, Amritanshu Jereminov, Marko Hug, Gabriela Pileggi, Larry Dept. of Electrical and Computer Engineering Carnegie Mellon University PittsburghPA United States Power Systems Laboratory ETH Zurich Switzerland

Recent advances in power system simulation have included the use of complex rectangular current and voltage (I-V) variables for solving the power flow and three-phase power flow problems. This formulation has demonstrated superior convergence properties over conventional polar coordinate based formulations for three-phase power flow, but has failed to replicate the same advantages for power flow in general due to convergence issues with systems containing PV buses. In this paper, we demonstrate how circuit simulation techniques can provide robust convergence for any complex I-V formulation that is derived from our split equivalent circuit representation. Application to power grid test systems with up to 104 buses demonstrates consistent global convergence to the correct physical solution from arbitrary initial conditions. Copyright © 2017, The Authors. All rights reserved.

关键词： Electric load flow

Aggregated load and generation equivalent circuit models with semi-empirical data fitting

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arXiv 2017年

作者： Pandey, Amritanshu Jereminov, Marko Li, Xin Hug, Gabriela Pileggi, Larry Dept. of Electrical and Computer Engineering Carnegie Mellon University PittsburghPA United States Power Systems Laboratory ETH Zurich Switzerland

In this paper we propose a semi-empirical modeling framework for aggregated electrical load and generation using an equivalent circuit formulation. The proposed models are based on complex rectangular voltage and current state variables that provide a generalized form for accurately representing any transmission and distribution components. The model is based on the split equivalent circuit formulation that was previously shown to unify power flow, three phase power flow, harmonic power flow, and transient analyses. Importantly, this formulation establishes variables that are analytical and are compatible with model fitting and machine learning approaches. The parameters for the proposed semi-empirical load and generation models are synthesized from measurement data and can enable real-time simulations for time varying aggregated loads and generation. Copyright © 2017, The Authors. All rights reserved.

关键词： Equivalent circuits

Folded orthogonal frequency division multiplexing for super-channel sub-banding 42

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Folded orthogonal frequency division multiplexing for super-...

42nd European Conference on Optical Communication, ECOC 2016

作者： Corcoran, Bill Zhu, Chen Song, Binhuang Lowery, Arthur Electro-Photonics Laboratory Dept. Electrical and Computer Systems Engineering Monash University VIC3800 Australia Australia

ISBN: (纸本)9783800742745

Orthogonal, periodic-sinc-shaped sub-carrier spectra allow multi-carrier bands with the precise, rectangular frequency definition of Nyquist-WDM. Experimental demonstration of these 'folded' OFDM bands shows a 0.5-1.7-dB implementation penalty, allowing 520-Gb/s super-channel transmission over 4160 km. © VDE VERLAG GMBH. Berlin. Offenbach.

关键词： Orthogonal frequency division multiplexing

Electronic Excitations in Complex Molecular Environments: Many-Body Green’s Functions Theory in VOTCA-XTP

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arXiv 2018年

作者： Wehner, Jens Brombacher, Lothar Brown, Joshua Junghans, Christoph Çaylak, Onur Khalak, Yuriy Madhikar, Pranav Tirimbò, Gianluca Baumeier, Björn Max Planck Institute for Polymer Research Ackermannweg 10 MainzD-55128 Germany Eindhoven University of Technology Department of Mathematics and Computer Science & Institute for Complex Molecular Systems P.O. Box 513 Eindhoven5600MB Netherlands Dept. of Electrical Computer and Energy Engineering University of Colorado Boulder 425 UCB BoulderCO80309 United States Renewable and Sustainable Energy Institute University of Colorado Boulder 4001 Discovery Dr BoulderCO80303 United States Computer Computational and Statistical Sciences Division Los Alamos National Laboratory Los AlamosNM87545 United States Eindhoven University of Technology Department of Mathematics and Computer Science & Institute for Complex Molecular Systems P.O. Box 513 Eindhoven5600MB Netherlands

Many-body Green’s functions theory within the GW approximation and the Bethe-Salpeter Equation (BSE) is implemented in the open-source VOTCA-XTP software, aiming at the calculation of electronically excited states in complex molecular environments. Based on Gaussian-type atomic orbitals and making use of resolution of identify techniques, the code is designed specifically for non-periodic systems. Application to the small molecule reference set successfully validates the methodology and its implementation for a variety of excitation types covering an energy range from 2-8 eV in single molecules. Further, embedding each GW -BSE calculation into an atomistically resolved surrounding, typically obtained from Molecular Dynamics, accounts for effects originating from local fields and polarization. Using aqueous DNA as a prototypical system, different levels of electrostatic coupling between the regions in this GW -BSE/MM setup are demonstrated. Particular attention is paid to charge-transfer (CT) excitations in adenine base pairs. It is found that their energy is extremely sensitive to the specific environment and to polarization effects. The calculated redshift of the CT excitation energy compared to a nucelobase dimer treated in vacuum is of the order of 1 eV, which matches expectations from experimental data. Predicted lowest CT energies are below that of a single nucleobase excitation, indicating the possibility of an inital (fast) decay of such an UV excited state into a bi-nucleobase CT exciton. The results show that VOTCA-XTP’s GW -BSE/MM is a powerful tool to study a wide range of types of electronic excitations in complex molecular environments. Copyright © 2018, The Authors. All rights reserved.

关键词： Quantum chemistry

Steady-state analysis of power system harmonics using equivalent split-circuit models

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Steady-state analysis of power system harmonics using equiva...

2016 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT Europe 2016

作者： Jereminov, Marko Pandey, Amritanshu Bromberg, David M. Li, Xin Hug, Gabriela Pileggi, Larry Dept. of Electrical and Computer Engineering Carnegie Mellon University PittsburghPA United States Power Systems Laboratory ETH Zurich Switzerland

ISBN: (纸本)9781509033584

In this paper we introduce a novel algorithm for harmonic steady-state analysis of power systems that is based on the equivalent split-circuit models recently introduced for power flow analysis. By using an equivalent circuit with current and voltage as the state variables, we extend the harmonic balance method that is used for nonlinear circuit simulation in the frequency domain to capture the frequency harmonics and inter-harmonics induced into a power grid due to nonlinear components. This enables the direct incorporation of physics-based steady-state models of power electronics and smart grid devices directly within the power-system simulation framework. For demonstration, steady-state models of a diode and a nonlinear core saturation inductor are derived and incorporated into the steady-state models of a three-phase full bridge rectifier and a magnetic core saturation transformer. These components are simulated within the proposed power flow analysis framework for a multi-bus power system. © 2016 IEEE.

关键词： Power electronics

Statistical QoS-driven power allocation over underwater cognitive acoustic networks 11

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Statistical QoS-driven power allocation over underwater cogn...

11th ACM International Conference on Underwater Networks and systems, WUWNet 2016

作者： Wang, Jingqing Zhang, Xi Networking and Information Systems Laboratory Dept. of Electrical and Computer Engineering Texas A and M University College StationTX77843 United States

ISBN: (纸本)9781450346375

As a critical technique to support the multimedia services, the statistical quality-of-service (QoS) technique has been proved to be effective in statistically guaranteeing delay-bounded video transmissions over the time-varying wireless channels. On the other hand, since both the natural acoustic systems and artificial acoustic systems use the acoustic channels, the spectrum resource is severely limited in underwater wireless networks. Researchers have proposed the underwater cognitive acoustic network (UCAN) to achieve the environment-friendly and spectrum-efficient transmissions over acoustic channels. However, how to efficiently integrate the UCAN under the statistical QoS constraints is still an open problem. To overcome this difficulty, we propose the QoS-driven power allocation scheme over UCAN. In particular, we propose and analyze the underwater cognitive system models and develop the optimal power allocation scheme in cognitive acoustic scenario udder statistical QoS requirements. Also conducted is a set of simulations which evaluate the system performance over UCAN. © 2016 ACM.

关键词： Cognitive systems