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Diagnosis of Oscillatory Transients Generated by Switching of Capacitor Banks using MPA

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Diagnosis of Oscillatory Transients Generated by Switching o...

2019 IEEE PES Conference on Innovative Smart Grid Technologies, ISGT Latin America 2019

作者： Hoffmann, Alessandra B. G. Beuter, Carlos H. Pessoa, André L. S. Oleskovicz, Mario Alvarez Ferreira, Liz R. Department of Electrical and Computer Engineering EESC University of São Paulo São Carlos SP Brazil Itaipu Technological Park PTI Automation and Simulation of Electrical Systems Laboratory Lasse Foz do Iguaçu PR Brazil

ISBN: (纸本)9781538695678

An Oscillatory Transient (OT) can occur in any part of an Electric Power System (EPS), and its basic characteristics are short duration and considerable variances of the amplitude of the voltage and frequencies involved. Focusing on a medium voltage distribution system, one of the main causes of the OT is the capacitor bank switching, which should be differentiated from other situations that may occur. In this research, we present the diagnostic (identification and extraction of characteristics) of OTs generated by the switching of capacitor banks by applying the Matching Pursuit Algorithm (MPA), that is based on a structured data dictionary. The Golden Search (GS) was used to find the characteristic parameters of the OT. The adopted methodology provided a sensible improvement in the search of the parameters, where the number of iterations was reduced and the estimations were stable. Sensitivity tests of the obtained parameters indicated their relevance for the data dictionary that was used. Based on this approach, it was possible to identify the amplitude (instantaneous value) of the OT as well as its duration. The use of the MPA enables researches with diverse signals, where the concern may be linked to the need to identify the origin of the OT observed on a particular EPS. This analysis, for example, can support areas related to power quality and also protection of electrical power systems. © 2019 IEEE.

关键词： Electric power system protection

Non-linear state-space model identification from video data using deep encoders

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arXiv 2020年

作者： Beintema, Gerben I. Toth, Roland Schoukens, Maarten Department of Electrical Engineering Eindhoven University of Technology Eindhoven5600 MB Netherlands Systems and Control Laboratory Institute for Computer Science and Control Kende u. 13-17 BudapestH-1111 Hungary

Identifying systems with high-dimensional inputs and outputs, such as systems measured by video streams, is a challenging problem with numerous applications in robotics, autonomous vehicles and medical imaging. In this paper, we propose a novel non-linear state-space identification method starting from high-dimensional input and output data. Multiple computational and conceptual advances are combined to handle the high-dimensional nature of the data. An encoder function, represented by a neural network, is introduced to learn a reconstructability map to estimate the model states from past inputs and outputs. This encoder function is jointly learned with the dynamics. Furthermore, multiple computational improvements, such as an improved reformulation of multiple shooting and batch optimization, are proposed to keep the computational time under control when dealing with high-dimensional and large datasets. We apply the proposed method to a video stream of a simulated environment of a controllable ball in a unit box. The study shows low simulation error with excellent long term prediction capability of the model obtained using the proposed method. © 2020, CC BY.

关键词： Large dataset

Prognostic Condition Monitoring for Wind Turbine Drivetrains via Generator Current Analysis

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Chinese Journal of electrical engineering 2018年第3期4卷 80-89页

作者： Wei Qiao Liyan Qu Power and Energy Systems Laboratory Department of Electrical and Computer EngineeringUniversity of Nebraska-LincolnLincolnNE 68588-0511USA

Maintenance costs account for a significant portion of the total cost of electricity generated by wind *** in the wind power industry,maintenance is mainly performed on regular schedules or when significant damage occurs in a wind turbine making it inoperable,instead of being determined by the actual condition of the wind *** the total maintenance costs,approximately 25%~35%is related to regularly scheduled preventive maintenance and 65%~75%to unscheduled corrective *** reduce the failure rate and level and maintenance costs and improve the availability,reliability,safety,and lifespans of wind turbines,it is desirable to perform condition-based predictive maintenance for wind turbines,which will require a high-fidelity online prognostic condition monitoring system(CMS)for fault diagnosis and prognosis and remaining useful life(RUL)prediction of wind *** of the existing wind turbine CMSs are based on vibration monitoring and have no or limited capability in fault prognosis and RUL *** to vibration monitoring,the prognostic condition monitoring techniques based on generator current signal analysis proposed recently have significant advantages in terms of cost,hardware complexity,implementation,and *** paper discusses the principles and challenges of using generator current signals for prognostic condition monitoring of wind turbine drivetrains and presents an overview of recent advancements in this area.

关键词： Current signal drivetrain fault diagnosis fault prognosis prediction prognostic condition monitoring remaining useful life(RUL) wind turbine

Analysis of Harmonic and Interharmonic Components by Using an Improved Recursive Algorithm

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Analysis of Harmonic and Interharmonic Components by Using a...

2019 IEEE PES Conference on Innovative Smart Grid Technologies, ISGT Latin America 2019

作者： Alvarez Ferreira, Liz R. Beuter, Carlos H. Hoffmann, Alessandra B. G. Pessoa, André L. S. Oleskovicz, Mário Itaipu Technological Park PTI Automation and Simulation of Electrical Systems Laboratory Lasse Foz do Iguaçu PR Brazil Department of Electrical and Computer Engineering EESC University of São Paulo São Carlos SP Brazil

ISBN: (纸本)9781538695678

Spectral leakage is a phenomenon that is considered a problem and occurs when Discrete Fourier Transform (DFT) is used as a tool to identify harmonic components in a frequency spectrum of electric signals, which contains asynchronous sampling or interharmonic components. It may cause errors in presented results that may affect signal analysis. Therefore, application of a technique or combination of techniques is necessary, in order to better characterize harmonic and interharmonic components and enable extraction of their representative factors. In this context, this research aims at estimating frequencies and amplitudes interharmonic present in a signal. This paper proposes a new approach method, based on Group-harmonic Power Minimizing (GPM) and Recursive Group-harmonic Power Minimizing (RGPM) algorithms. The new proposal establishes an identification threshold and is more accurate when compared to the IEC 61000-4-7 standard, recommended for this kind of problem as it detects not only the 5 Hz minimal spectral resolution, but also frequency components of intermediate location with noise. Results indicate a satisfactory characterization of predominant interharmonic components, with low deviation level, both in range and in associated frequency. © 2019 IEEE.

关键词： Discrete Fourier transforms

Spatial Multiplexing with Limited RF Chains: Generalized Beamspace Modulation (GBM) for mmWave Massive MIMO

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Spatial Multiplexing with Limited RF Chains: Generalized Bea...

作者： Gao, Shijian Cheng, Xiang Yang, Liuqing Department of Electrical and Computer Engineering Colorado State University Fort CollinsCO United States Department of Electronics State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computing Sciences Peking University Beijing China

Millimeter wave (mmWave) massive multiple-input multiple-output (mMIMO) has been recognized as a promising candidate for 5G communications for its capability of supporting Gb/s transmission. However, it is a common exercise to deploy a limited number of radio-frequency (RF) chains at mmWave mMIMO transceivers due to hardware complexity and cost. As a result, the potential multiplexing gain (MG), which is restricted by the smaller number of RF chains at the transmitter and receiver, is markedly compromised. In order to boost the MG and spectral efficiency (SE), we innovatively develop a novel index modulation termed as the generalized beamspace modulation (GBM). The acquisition of (sub-)beamspace is owing to a natural exploitation of the unique features of mmWave mMIMO. Based on the (sub-)beamspace, a complete GBM transceiver is designed and optimized. Unlike existing alternatives that are largely digital based, our GBM is tailored for the hybrid structure of mmWave mMIMO and can, thereby, realize efficient spatial multiplexing despite the limited RF chains. Extensive analyses and simulations have demonstrated remarkable superiority of GBM over existing counterparts in terms of the error performance and SE. © 1983-2012 IEEE.

关键词： Modulation

Post-quantum cryptographic hardware primitives

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arXiv 2019年

作者： Bu, Lake Agrawal, Rashmi Cheng, Hai Kinsy, Michel A. Adaptive and Secure Computing Systems Laboratory Department of Electrical and Computer Engineering Boston University

The development and implementation of post-quantum cryptosystems have become a pressing issue in the design of secure computing systems, as general quantum computers have become more feasible in the last two years. In this work, we introduce a set of hardware post-quantum cryptographic primitives (PCPs) consisting of four frequently used security components, i.e., public-key cryptosystem (PKC), key exchange (KEX), oblivious transfer (OT), and zero-knowledge proof (ZKP). In addition, we design a high speed polynomial multiplier to accelerate these primitives. These primitives will aid researchers and designers in constructing quantum-proof secure computing systems in the post-quantum era. Copyright © 2019, The Authors. All rights reserved.

关键词： Field programmable gate arrays (FPGA)

Efficient robust dispatch of combined heat and power systems

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arXiv 2020年

作者： Jiang, Yibao Wan, Can Botterud, Audun Song, Yonghua Dong, Zhao Yang College of Electrical Engineering Zhejiang University Hangzhou310027 China Laboratory for Information and Decision Systems Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical and Computer Engineering University of Macau China School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW2052 Australia

Combined heat and power systems facilitate efficient interactions between individual energy sectors for higher renewable energy accommodation. However, the feasibility of operational strategies is difficult to guarantee due to the presence of substantial uncertainties pertinent to renewable energy and multi-energy loads. This paper proposes a novel efficient robust dispatch model of combined heat and power systems based on extensions of disturbance invariant sets. The approach has high computational efficiency and provides flexible and robust strategies with an adjustable level of conservativeness. In particular, the proposed robust dispatch method obtains operational strategies by solving a nominal uncertainty-free dispatch problem, whose complexity is identical to a deterministic problem. The robustness against uncertainties is enhanced by endowing the nominal dispatch model with properly tightened constraints considering time-variant uncertainty sets. Towards this end, a novel direct constraint tightening algorithm is developed based on the dual norm to calculate multi-period tightened constraints efficiently without linear programming iterations. Furthermore, the budget uncertainty set is newly combined with constraint tightening to flexibly adjust the conservativeness level of robust solutions. The effectiveness of the proposed robust method is demonstrated in simulation studies of a test system in terms of computational efficiency, decision robustness and cost optimality. Copyright © 2020, The Authors. All rights reserved.

关键词： Renewable energy resources

A lightweight mceliece cryptosystem co-processor design

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arXiv 2019年

作者： Bu, Lake Agrawal, Rashmi Cheng, Hai Kinsy, Michel A. Adaptive and Secure Computing Systems Laboratory Department of Electrical and Computer Engineering Boston University

Due to the rapid advances in the development of quantum computers and their susceptibility to errors, there is a renewed interest in error correction algorithms. In particular, error correcting code-based cryptosystems have reemerged as a highly desirable coding technique. This is due to the fact that most classical asymmetric cryptosystems will fail in the quantum computing era. Quantum computers can solve many of the integer factorization and discrete logarithm problems efficiently. However, code-based cryptosystems are still secure against quantum computers, since the decoding of linear codes remains as NP-hard even on these computing systems. One such cryptosystem is the McEliece code-based cryptosystem. The original McEliece code-based cryptosystem uses binary Goppa code, which is known for its good code rate and error correction capability. However, its key generation and decoding procedures have a high computation complexity. In this work we propose a design and hardware implementation of an public-key encryption and decryption co-processor based on a new variant of McEliece system. This co-processor takes the advantage of the non-binary Orthogonal Latin Square Codes to achieve much smaller computation complexity, hardware cost, and the key size. Copyright © 2019, The Authors. All rights reserved.

关键词： Integrated circuit design

Low density majority codes and the problem of graceful degradation

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arXiv 2019年

作者： Roozbehani, Hajir Polyanskiy, Yury Laboratory of Information and Decision Systems MIT Department of Electrical Engineering and Computer Science MIT

We study a problem of constructing codes that transform a channel with high bit error rate (BER) into one with low BER (at the expense of rate). Our focus is on obtaining codes with smooth ("graceful") input-output BER curves (as opposed to threshold-like curves typical for long error-correcting codes). This paper restricts attention to binary erasure channels (BEC) and contains three contributions. First, we introduce the notion of Low Density Majority Codes (LDMCs). These codes are non-linear sparse-graph codes, which output majority function evaluated on randomly chosen small subsets of the data bits. This is similar to Low Density Generator Matrix codes (LDGMs), except that the XOR function is replaced with the majority. We show that even with a few iterations of belief propagation (BP) the attained input-output curves provably improve upon performance of any linear systematic code. The effect of non-linearity bootstraping the initial iterations of BP, suggests that LDMCs should improve performance in various applications, where LDGMs have been used traditionally. Second, we establish several two-point converse bounds that lower bound the BER achievable at one erasure probability as a function of BER achieved at another one. The novel nature of our bounds is that they are specific to subclasses of codes (linear systematic and non-linear systematic) and outperform similar bounds implied by the area theorem for the EXIT function. Third, we propose a novel technique for rigorously bounding performance of BP-decoded sparse-graph codes (over arbitrary binary input-symmetric channels). This is based on an extension of ***’s lemma to the χ2-information and a new characterization of the extremality under the less noisy order. Copyright © 2019, The Authors. All rights reserved.

关键词： Belief propagation