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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Hamidreza Nazaripouya Hossein Mokhtari The Center of Excellence in Power System Management & Control Sharif University of Technology Iran

In this paper, optimal control strategy is applied to parallel three-phase inverters using SVPWM technique. The three-phase system is transformed to a synchronous-stationary frame, suitable cost functions are defined, and the switching schemes are determined for the inverters. The control strategy minimizes the circulating current between the inverters, therefore, proper load sharing scheme is achieved. Simulations are performed for steady state and load change operation, and the results which show the suitability of the controller are provided.

关键词： Optimal control Inverters Space vector pulse width modulation Uninterruptible power systems power system reliability Voltage control systems Costs State-space methods Equations

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Optimal DG placement in distribution systems using cost/worth analysis

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World Academy of Science, Engineering and technology 2009年 37卷 746-753页

作者： Ahmadigorji, M. Abbaspour, A. Rajabi-Ghahnavieh, A. Fotuhi-Firuzabad, M. Centre of Excellence in Power System Control and Management Department of Electrical Engineering Sharif University of technology Tehran Iran

DG application has received increasing attention during recent years. The impact of DG on various aspects of distribution system operation, such as reliability and energy loss, depend highly on DG location in distribution feeder. Optimal DG placement is an important subject which has not been fully discussed yet. This paper presents an optimization method to determine optimal DG placement, based on a cost/worth analysis approach. This method considers technical and economical factors such as energy loss, load point reliability indices and DG costs, and particularly, portability of DG. The proposed method is applied to a test system and the impacts of different parameters such as load growth rate and load forecast uncertainty (LFU) on optimum DG location are studied.

关键词： Dynamic programming

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Reliability-based selection of wind turbines for large-scale wind farms

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World Academy of Science, Engineering and technology 2009年 37卷 734-740页

作者： Fotuhi-Firuzabad, M. Dobakhshari, A. Salehi Centre of Excellence in Power System Control and Management Department of Electrical Engineering Sharif University of Technology Tehran Iran Department of Electrical Engineering Sharif University of Technology Tehran Iran

This paper presents a reliability-based approach to select appropriate wind turbine types for a wind farm considering site-specific wind speed patterns. An actual wind farm in the northern region of Iran with the wind speed registration of one year is studied in this paper. An analytic approach based on total probability theorem is utilized in this paper to model the probabilistic behavior of both turbines' availability and wind speed. Well-known probabilistic reliability indices such as loss of load expectation (LOLE), expected energy not supplied (EENS) and incremental peak load carrying capability (IPLCC) for wind power integration in the Roy Billinton Test system (RBTS) are examined. The most appropriate turbine type achieving the highest reliability level is chosen for the studied wind farm.

关键词： Wind Turbine Generators

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Robust controller design for governing steam turbine power generators

Robust controller design for governing steam turbine power g...

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International Conference on Electrical Machines and systems (ICEMS)

作者： H. Nademi F. Tahami Damavand Combined Cycle Power Plant Damavand Power Generation Management Company Tehran Iran Center of excellence in Power System Management & Control Sharif University of Technology Tehran Iran

The turbine control system is one of the key control loops in the dynamic performance of steam power generation units. In this paper a multivariable PID controller is designed for the governing system of steam turbine power generators. The necessary and sufficient conditions for existence of a strong robust H ¿ dynamic compensator are established in terms of linear matrix inequality (LMI) approach. This controller is designed in succeeding to the existing proportional controller in a power plant. To reach to this goal, the complete dynamic model of an actual turbine-generator including the governor, turbine and generator, are derived. Simulation results show that proposed controller has good tracking and disturbance rejection properties despite the variations in the system parameters.

关键词： Robust control Turbines power generation control systems Proportional control Three-term control Sufficient conditions Robustness Linear matrix inequalities power system modeling

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Application of Random PWM Techniques for Reducing the Electromagnetic Interference of Vienna Rectifiers in Distribution power system

Application of Random PWM Techniques for Reducing the Electr...

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2009 IEEE 6th International power Electronics and Motion control Conference-ECCE Asia

作者： Shahriyar Kaboli Amir Hossein Rajaei Aras Sheikhi Center of Excellence in Power System Management and Control Department of Electrical Engineering Sharif University of Technology Department of Electrical and Computer Engineering Tarbiat Modares University

Random pulse width modulation (RPWM) technique has been employed to generate the control signals of Vienna-type rectifier. This technique is compared to two conventional techniques (Hysteresis-band and ramp comparison with fix frequency carrier signal). Simulation results are illustrated for three approaches. The results verify significantly reduction of high frequency harmonics magnitude;and consequently overcome electromagnetic interference (EMI) problem in this active type of rectifier.

关键词： PWM Application of Random PWM Techniques for Reducing the Electromagnetic Interference of Vienna Rectifiers in Distribution power system

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Reliability evaluation of HV substations in the presence of Fault Current Limiter

Reliability evaluation of HV substations in the presence of ...

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power Tech Conference

作者： I. Rahmati M. Fotuhi-Firuzabad Privatization Bureau of Ministry of Energy of Iran Tehran Iran Center of Excellence in Power System Control and Management Department of Electrical Engineering Sharif University of Technology Tehran Iran

Short circuit current is one of the major threats for power system stability. power system should have the ability to detect and clear these faults within a specified time. The protection system can clear the faults only if the interruption capability of the circuit breakers is higher than the fault level. Expansion of the grid and installation of new power on the scale that is envisaged will require practical solutions to a number of technical challenges. One of the technical challenges is fault level management as system expansion often results in increased fault levels beyond the design limits of the existing switchgears. Replacing the old equipments particularly circuit breakers with the new ones having higher interruption capability is one way to overcome this problem. This, however, is not a cost-effective management of fault levels. Using Fault Current Limiters can be an alternative to avoid this high investment cost. In this paper, application of fault current limiter in substation reliability enhancement is presented. The result of the investigations carried out to assess the impacts of FCL application on substation reliability.

关键词： Substations Fault current limiters Circuit faults power system reliability power system stability power system protection Circuit breakers Short circuit currents power system faults Electrical fault detection

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Impacts of Loop Restoration Strategy on distribution system reliability

Impacts of Loop Restoration Strategy on distribution system ...

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power Tech Conference

作者： Shahram Kazemi Mahmud Fotuhi-Firuzabad Majid Sanaye-Pasand Matti Lehtonen Department of Electrical Engineering Helsinki University of Technology Espoo Finland Department of Electrical Engineering Sharif University of Technology Tehran Iran Center of Excellence in Power System Control and Management Department of Electrical Engineering Sharif University of Technology Tehran Iran School of Electrical and Computer Engineering University of Tehran Tehran Iran

Implementation of distribution automation (DA) in electric power distribution systems can result in customer satisfaction with improved reliability, consistent quality and high-tech services. Loop restoration strategy (LRS) is a special DA method in the feeder level which is used by electric utilities to improve distribution system reliability. The effects of the implemented LRS on the reliability indices of a given distribution system mainly depend on its automatic control system (ACS). Selecting the type of ACS of LRS by electric utilities relies on the level of improvement required at load points and system oriented reliability indices. A step by step evaluation procedure is proposed in this paper to quantitatively assess the impacts of two common types of ACS of LRS on reliability indices of a distribution reliability test system.

关键词： Circuit faults Frequency power system reliability power system restoration Automation Customer satisfaction power industry Automatic control Fuses Protection

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Optimal placement of Unified power Flow controllers (UPFCs) using Mixed-Integer Non-Linear Programming (MINLP) method

Optimal placement of Unified Power Flow Controllers (UPFCs) ...

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IEEE General Meeting power& Energy Society

作者： F. Aminifar M. Fotuhi-Firuzabad A. Khodaei S. O. Faried Centre of Excellence in Power System Control and Management Electrical Engineering Department Sharif University of Technology Tehran Iran Electrical and Computer Engineering Department Illinois Institute of Technology Chicago IL USA Department of Electrical Engineering University of Saskatchewan Saskatoon Canada

Utilization of unified power flow controllers (UPFCs) can be more beneficial in the restructured power systems due to their capabilities in increasing the transmission line capacities as well as shunt reactive compensation. So, these devices should be installed such that the most benefit can be gained. In this paper, the problem of optimal placement of UPFCs is solved using Mixed-Integer Non-Linear Programming (MINLP) method. Hence, the problem is completely formulated based on this method and is solved using available commercial solvers. The salient feature of this method is having potential to simultaneously determine the optimal location of multi UPFCs. Also, since a full AC Optimal power Flow (AC-OPF) is fulfilled during this process, functional parameters of UPFCs and results of OPF are obtained finally. Some case studies are examined to illustrate the effectiveness of the proposed formulation.

关键词： Load flow Optimal control Reactive power Voltage Nonlinear control systems control systems Admittance power systems power transmission lines power system control

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Optimal allocation of spinning reserve in a restructured power system using particle swarm optimization

Optimal allocation of spinning reserve in a restructured pow...

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IEEE Canadian Conference on Electrical and Computer Engineering, CCECE 2008

作者： Hajian-Hoseinabadi, H. Fotubi-Firuzabad, M. Hajian, M. IEEE Department of Electrical Engineering Sharif University of Technology Tehran Iran Center of Excellence in Power System Control and Management Electrical Engineering Department Sharif University of Technology

ISBN: (纸本)9781424416431

A reasonable amount of spinning reserve is essential to satisfy system security constraints when the power system encounters a contingency. Most ofthe methods previously developed for spinning reserve assessment ignore the probabilistic aspects of system components. This paper presents the design of a market for energy and spinning reserve services. This dispatching method has been developed to minimize the cost associated with theses services while maintaining the system security. Particle swarm optimization (PSO) is used for determining the global optimal solution for this dispatch problem. The effectiveness of the proposed approach is examined by application to the IEEE Reliability Test system (RTS). The results obtained with the proposed approach are presented and compared with those of Genetic Algorithms (GA). © 2008 IEEE.

关键词： Genetic algorithms

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Reliability assessment of distribution system with distributed generation

Reliability assessment of distribution system with distribut...

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National Proceedings power and Energy Conference (PECon)

作者： Pedram Jahangiri Mahmud Fotuhi-Firuzabad Department of Electrical Engineering Center of Excellence in Power System Control and Management Sharif University of Technology Tehran Iran

Reliability assessment is of primary importance in designing and planning distribution systems that operate in an economical manner with minimal interruption of customer loads. Distributed generation (DG) is expected to play an increasing role in emerging power systems because they use different type of resources and technologies to serve energy to power systems. DG is expected to improve the system reliability as its backup generation. Since DG units are subject to failures as all other generation units, the random behavior of these units must be taken into account in the analysis. Existence of DG units in a distribution system will effect on restoration time of load points. In this paper, an algorithm for assessing restoration time of load points for a radial distribution system with back up DG units is presented. The Impacts of DG units, their location, number of DG units in each location and their availability, on distribution system reliability are investigated using a real distribution network in Tehran utility/Iran.

关键词： Distributed control power system reliability power system economics power generation economics power system planning Standby generators Fuel economy Wind energy generation Circuit faults power system analysis computing

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