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A wavelet packet based method for adaptive single-pole auto-reclosing

Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第12期11卷 1016-1024页

作者： Sadegh JAMALI Navid GHAFFARZADEH Centre of Excellence in Power Systems Automation and Operation Iran University of Science and Technology Tehran Iran

We present a new algorithm for adaptive single-pole auto-reclosing of power transmission lines using wavelet packet transform. The db8 wavelet packet decomposes the faulted phase voltage waveform to obtain the coefficients of the nodes 257, 259 to 262. An index is then defined from the sum of the energy coefficients of these nodes. By evaluating the index, transient and permanent faults, as well as the secondary arc extinction instant, can be identified. The significant advantage of the proposed algorithm is that it does not need a threshold level and therefore its performance is independent of fault location, line parameters, and operating conditions. Moreover, it can be used in transmission lines with reactor compensation. The proposed method has been successfully tested under a variety of fault conditions on a 400 kV overhead line of the Iranian National Grid using the Electro-Magnetic Transient Program (EMTP). The test results validated the algorithm’s ability in distinguishing between transient arcing and permanent faults and determining the instant of secondary arc extinction.

关键词： Adaptive auto-reclosing Arcing faults Permanent faults Transmission lines Wavelet packet transform

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A comprehensive circuit model for partial discharge activities in cable insulation due to electrical treeing

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INTERNATIONAL JOURNAL OF ELECTRICAL power & ENERGY systems 2013年第1期44卷 646-655页

作者： Pour, A. Najafi Shahrtash, S. M. Center of Excellence for Power System Automation and Operation Iran University of Science and Technology (IUST) Iran

A new comprehensive circuit model is proposed for electrical trees in cable insulation to be used in partial discharge (PD) analyses. Simple relations are presented for each of circuit components. The effect of tree's constructional parameters (such as length, growth angle and type), cable and insulation dimension (such as conductor radius and insulation thickness), needle dimension, temperature and insulation aging are considered in the proposed model. The patterns (pulse sequences, phi-q-n and phi-n) extracted from the proposed model are in a good agreement with the published experimental patterns under different conditions. Moreover, the model is fully compatible with the software packages, such as EMTP, that can simulate pulse propagation along cable networks. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Cable insulation Partial discharge Electrical tree Circuit model EMTP

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Robust design of static synchronous series compensator-based stabilizer for damping inter-area oscillations using quadratic mathematical programming

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第4期11卷 296-306页

作者： Mahmoud Reza SHAKARAMI Ahad KAZEMI Center of Excellence for Power System Automation and Operation Department of Electrical EngineeringIran University of Science and Technology

This paper presents a procedure for designing a supplementary damping stabilizer for a static synchronous series compensator(SSSC) in multi-machine power *** objective is to shift the lightly damped inter-area modes toward the prescribed stability region.A lead-lag stabilizer is used to demonstrate this technique,in which a particular measure of stabilizer gain is considered as an objective *** of the problem for phase-lead and lag structures are *** objective function with the constraints is formed as a quadratic mathematical programming *** robust design,the parameters of the stabilizer are calculated under various operating *** types of SSSC-based stabilizer have been presented and *** results including eigenvalue analysis and the nonlinear simulations on the 4-and 50-machine power systems are pre-sented to show the effectiveness of the proposed method.

关键词： Inter-area oscillations Static synchronous series compensator(SSSC) Damping stabilizer Robust design Quadratic mathematical programming

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A new approach to DTC-ISVM for induction motor drive system fed by indirect matrix converter

A new approach to DTC-ISVM for induction motor drive system ...

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power Electronic and Drive systems and Technologies Conference

作者： Faraji, Vahid Arab Khaburi, Davood Center of Excellence for Power Systems Automation and Operation IUST Tehran Iran

ISBN: (纸本)9781612844213

In this paper a high performance Direct Torque Control (DTC) theme for the induction motor fed by indirect matrix converter is proposed and investigated. Since the indirect matrix converter has an intermediate dc link, the control process can be separated into rectifier stage modulation and inverter stage modulation. Indirect space vector modulation (ISVM) for input current is applied on the rectifier bridge, while the inverter and motor can be seen as constant current load in DC link and ISVM for output voltage is applied on the inverter bridge. The modulation processes of rectifier stage and inverter stage are considered simultaneously. This paper investigates the use of four-step commutation strategy in rectifier bridge of indirect matrix converters to reduce problem of snubber circuit in the rectifier stage. By suitably selecting switching pattern, the electromagnetic torque ripple of the motor is effectively reduced. The simulation results of DTC system based on IMC and the comparison of motor performance under the proposed control system with respect to those obtained under conventional DTC confirm its effectiveness and accuracy. © 2011 IEEE.

关键词： Matrix converters

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Optimum allocation of FACTS devices in Fars Regional Electric Network using genetic algorithm based goal attainment

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 478-487页

作者： Mohsen GITIZADEH Mohsen KALANTAR Center of Excellence for Power System Automation and Operation Department of Electrical Engineering Iran University of Science and TechnologyTehran 16844 Iran

This paper presents a novel approach to find optimum locations and capacity of flexible alternating current transmission system (FACTS) devices in a power system using a multi-objective optimization function. Thyristor controlled series compensators (TCSCs) and static var compensators (SVCs) are the utilized FACTS devices. Our objectives are active power loss reduction, newly introduced FACTS devices cost reduction, voltage deviation reduction, and increase on the robustness of the security margin against voltage collapse. The operational and controlling constraints, as well as load constraints, were considered in the optimum allocation. A goal attainment method based on the genetic algorithm (GA) was used to approach the global optimum. The estimated annual load profile was utilized in a sequential quadratic programming (SQP) optimization sub-problem to the optimum siting and sizing of FACTS devices. Fars Regional Electric Network was selected as a practical system to validate the performance and effectiveness of the proposed method. The entire investment of the FACTS devices was paid off and an additional 2.4% savings was made. The cost reduction of peak point power generation implies that power plant expansion can be postponed.

关键词： Flexible alternating current transmission system (FACTS) devices allocation Multi-objective optimization Geneticalgorithm (GA) Goal attainment

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Optimal Day-ahead Dynamic Pricing of Grid-connected Residential Renewable Energy Resources Under Different Metering Mechanisms

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Journal of Modern power systems and Clean Energy 2023年第1期11卷 168-178页

作者： Kimia Parandeh Abed Bagheri Shahram Jadid Center of Excellence for Power System Automation and Operation School of Electrical EngineeringIran University of Science and Technology(IUST)TehranIran

Nowadays,grid-connected renewable energy resources have widespread applications in the electricity ***,providing household consumers with photovoltaic(PV)systems requires bilateral interfaces to exchange energy and *** addition,residential consumers’contribution requires guaranteed privacy and secured data *** dynamic pricing is one of the incentive-based demand response methods that has substantial effects on the integration of renewable energy resources with smart grids and social *** metering mechanisms of renewable energy resources such as feed-in tariffs,net metering,and net purchase and sale are important issues in power grid operation *** this paper,optimal condition decomposition method is used for dayahead dynamic pricing of grid-connected residential renewable energy resources under different metering mechanisms:feed-intariffs,net metering,and net purchase and sale in conjunction with carbon emission *** to the stochastic nature of consumers’load and PV system products,uncertainties are considered in a two-stage decision-making *** results demonstrate that the net metering with the satisfaction average of 68%for consumers and 32%for the investigated electric company leads to 28%total load *** the case of net purchase and sale mechanism,a satisfaction average of 15%for consumers and 85%for the electric company results in 11%total load *** feed-in-tariff mechanism,in spite of increased social welfare,load reduction does not take place.

关键词： Dynamic pricing renewable energy resources feed-in-tariffs net metering net purchase and sale stochastic decision-making

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A Wavelet based Pilot Protection Scheme for Series Compensated Line in Parallel with Another Line

A Wavelet based Pilot Protection Scheme for Series Compensat...

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43rd International-Universities-power-Engineering Conference

作者： Beris, Sadegh Shahamati Shahrtash, Seyed Mohammad Center of Excellence for Power Systems Automation and Operation (CEPSAO) Iran University of Science and Technology (IUST) Iran

ISBN: (纸本)9781424432943

In this paper a new algorithm to be implemented for protection of a series compensated transmission line which is in parallel with another line has been developed. The proposed algorithm is based on traveling wave theory and wavelet analysis, that structured on seeking for the time conformity of modulus maximas (TCMM) extracted at the both ends of the protected line. The performance of the algorithm has been investigated under different types of faults, fault resistances, fault inception angles (FIA) and compensation configurations. The results have been shown high dependability and security for the protection algorithm except for zero FIAs, which is the main problem in the transient based protection schemes.

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Assessment of restructured power systems security using Contingency Sensitivity Index

Assessment of restructured power systems security using Cont...

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40th North American power Symposium, NAPS2008

作者： Farahani, Vahraz Zamani Jadid, Shahram Center of Excellence for Power Systems Operation and Automation EE Dept. IUST Teharan Iran

ISBN: (纸本)9781424442836

Restructuring of power systems has introduced new alphabet to power industry. Combining the technical and economical parameters in restructured power system has opened the new horizon in power systems study. Traditionally, one of the most important aspects of power systems study is security. In this paper, the new index named Contingency Sensitivity Index (CSI) has been developed to show the severity of the restructured power system conditions with different energy prices in different locations according to the contingencies which happens in power systems. The basic of CSI calculation is totally related to Locational Marginal Price (LMP) changes. This index has been compared by different Vulnerability Indexes and has shown its efficiency. CSI can be used in generation/transmission expansion planning, coordination between market manager and system operator, and improving the operation of the power system. ©2008 IEEE.

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Resistor type superconducting fault current limiter: Optimum shunt resistance determination to enhance power system transient stability

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IEEJ Transactions on power and Energy 2009年第2期129卷 299-308+6页

作者： Hooshyar, Hossein Heydari, Hossein Savaghebi, Mehdi Sharifi, Reza Center of Excellence for Power System Automation and Operation Electrical Engineering Department Iran University of Science and Technology Tehran Iran

In power systems, Resistor type Superconducting Fault Current Limiters (RSFCL) can limit the prospective short-circuit currents to lower levels, so that the underrated switchgears can operate safely. Besides, RSFCLs can enhance the power system transient stability if they are accompanied by appropriate shunt resistances. This paper presents a method of optimum shunt resistance determination for transient stability improvement. The method is based on minimization of rotor kinetic energy oscillations. Meanwhile to make it more comprehensible, the method is utilized to determine the shunt resistances of three RSFCLs installed in a 9-bus 3-generator sample network. All of the simulations have been carried out by EMTP/ATP. The paper begins by modeling an RSFCL. Then RSFCL critical current determination is discussed in a model system. Finally, a method of optimum shunt resistance determination for transient stability improvement is presented. © 2009 The Institute of Electrical Engineers of Japan.

关键词： High temperature superconductors

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Calculating the transient behavior of grounding systems using inverse Laplace transform

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第3期12卷 250-262页

作者： Nabiollah RAMEZANI Seyed Mohammad SHAHRTASH Behshahr Branch Iran University of Science and TechnologyBehshahr 47137Iran Center of Excellence for Power Systems Automation and Operation Department of Electrical EngineeringIran University of Science and TechnologyTehran 16844Iran

This paper deals with a unified and novel approach for analyzing the frequency and time domain performance of grounding *** proposed procedure is based on solving the full set of Maxwell's equations in the frequency domain,and enables the exact computation of very near fields at the surface of the grounding grid,as well as far fields,by simple and accurate closed-form expressions for solving Sommerfeld *** addition,the soil ionization is easily considered in the proposed *** frequency domain responses are converted to the time domain by fast inverse Laplace *** results are validated and have shown acceptable accuracy.

关键词： Electromagnetic field Near-field computation High frequency performance Soil ionization Grounding system Fast inverse Laplace transform

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