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 Volume 6, 2011
Print ISSN: 1790-5060
E-ISSN: 2224-350X








Issue 1, Volume 6, January 2011

Title of the Paper:  IDCGA Based Evaluation of Network Losses Role in TNEP under Uncertainty in Demand


Authors: H. Hosseini, S. Jalilzadeh, A. Kimiyaghalam, A. Bagheri

Abstract: Transmission network expansion planning (TNEP) is an important component of power system planning. It determines the characteristic and performance of the future electric power network and influences the power system operation directly. Up till now, various methods have been presented for the solution of static TNEP (STNEP) problem. However, in all of them, STNEP problem has been solved regardless of the network losses role in TNEP under uncertainty in demand. Thus, in this paper, the role of network losses in STNEP problem is being studied under uncertainty in demand using an improved decimal codification genetic algorithm (IDCGA). The effectiveness of the proposed idea is tested on an actual transmission network of the Azerbaijan regional electric company, Iran. The results reveal that, considering the losses even for transmission expansion planning of a multi voltage level network with low load growth is caused that operational costs decreases considerably and the network satisfies the requirement of delivering electric power more safely and reliable to load centers.

Keywords: Transmission expansion planning, Uncertainty in demand, Network losses, IDCGA

Title of the Paper:  Identifying Factors of Energy Usage in Taiwan


Authors: Jui-Chen Yu, Hung-Jen Yang, Lung-Hsing Kuo, Hsieh-Hua Yang

Abstract: The purpose of this study was to identify the energy use in Taiwan. Logit regression analyses on a large micro-dataset reveal how energy use characteristics can help explain the energy. Using CR5.0 regression models, this paper explored the factors affecting energy demand conditional on energy forms, sectors and sources. Results suggest that explained models could be used as a well foundation for energy policy decision making.

Keywords: Factor, Energy Use, Energy Indicators, Model

Title of the Paper:  Robust Controller for Interleaved DC-DC Converters and Buck Inverter in Grid-Connected Photovoltaic Systems


Authors: Hassan Abouobaida, Mohamed Cherkaoui

Abstract: The present work describes the analysis, modeling and control of an interleaved Boost converters and Buck power inverter used as a DC-DC and DC-AC power conditioning stage for grid-connected photovoltaic (PV) systems. To maximize the steady-state input-output energy transfer ratio a backstepping controller is designed to assure output unity power factor and a Maximum Power Point Tracking (MPPT) algorithm to optimize the PV energy extraction. The achievement of the DC-AC conversion at unity power factor and the efficient PV’s energy extraction are validated with simulation results.

Keywords: MPPT, unity power factor, backstepping controller, Lyapunov

Issue 2, Volume 6, April 2011

Title of the Paper:  Modeling and Stability Analysis of AC-DC Power System with Controlled Rectifier and Constant Power Loads


Authors: K. Chaijarurnudomrung, K.-N. Areerak, K.-L. Areerak

Abstract: Power converters with their controls normally behave as a constant power load. This load can significantly degrade the system stability. Therefore, the system dynamic model is very importance because it can be used for stability analysis. It is well known that power converter models are time-varying because of their switching behaviours. This paper presents the DQ modeling method to eliminate the switching action to achieve time-invariant model for the stability analysis. The power system studied is the AC distribution system. The small-signal model of the power system is obtained by using a linearization technique. The small-signal simulations are used to validate the DQ linearized model. The reported model is then used for the stability analysis via the classical control theory. The results show that an excellent agreement between the mathematical model and the three-phase benchmark model is achieved.

Keywords: Constant power loads, DQ method, simulation, modeling, controlled rectifier, stability analysis

Title of the Paper:  Wavelet Entropy Based Algorithm for Fault Detection and Classification in FACTS Compensated Transmission Line


Authors: Amany M. El-Zonkoly, Hussein Desouki

Abstract: Distance protection of transmission lines including advanced flexible AC transmission system (FACTS) devices has been a very challenging task. FACTS devices of interest in this paper are static synchronous series compensators (SSSC) and unified power flow controller (UPFC). In this paper, a new and simple algorithm is proposed to detect and classify the fault and identify the fault position in a transmission line with respect to a FACTS device placed in the midpoint of the transmission line. The algorithm is suitable for the analysis of different types of faults. Discrete wavelet transformation and wavelet entropy calculations are used to analyze during fault current and voltage signals of the compensated transmission line. The proposed algorithm is very simple and accurate in fault detection and classification. A variety of fault cases and simulation results are introduced to show the effectiveness of such algorithm.

Keywords: Fault detection; Power systems; Wavelet transform; Entropy calculation; FACTS; SSSC; UPFC

Title of the Paper:  The Influence of Static Contactor on the THD Generated by Currents on a High Frequency Electro Thermal Installation with Electromagnetic Induction


Authors: Raluca Rob, Ioan Sora, Caius Panoiu, Manuela Panoiu

Abstract: This paper presents an analysis of the electrical parameters resulted during the functioning simulation of a high frequency electro thermal installation with electromagnetic induction. Modeling and simulation the electrical scheme were made using PSCAD-EMTDC tool. The authors followed the influence of the static contactor regarding the THD generated by phase currents in secondary winding of power transformer.

Keywords: Electro thermal installation, electromagnetic induction, harmonic distortion

Issue 3, Volume 6, July 2011

Title of the Paper:  Active Power Influence on the Electrical Parameters of an Electro Thermal Installation with Electromagnetic Induction


Authors: Caius Panoiu, Raluca Rob, Manuela Panoiu, Gabriel Popa

Abstract: In this paper followed the variation of the electrical parameters that characterize the functioning of an electro thermal installation with electromagnetic induction. The measurements were made using a three phase power quality analyzer, CA 8334B. There were presented two different situations: the HF transformer with 5:1 and 3:1 transformation ratio. In order to recover the recordings, the transients, the alarms and the screen copies, there was used the QualiStar View software.

Keywords: Electro thermal installation, electrical parameters

Title of the Paper:  The V-CURVE Analysis and Study of Synchronous Motors Using MATLAB Program


Authors: Aree A. Muhammad

Abstract: Today Synchronous motors are widely used in modern societies: industrial, commercial, agricultural, and domestic applications as constant-speed motors or as compensators for reactive power control in large power systems. Also understanding the machine’s behaviour and determining its equivalent network and performance characteristics are of prime importance to a power engineer. This paper explains the constructional features and operating principles of the synchronous motor performance, the effects of load and field excitation on the synchronous motor are investigated. The V-curve of a synchronous machine is analysed, studied, and a review of various excitation systems provided. MATLAB program is used to verify this study.

Keywords: Synchronous motor, over excitation, vector diagrams, V-curves

Title of the Paper:  Line Configuration Analysis of an Overhead Ground Wire the Effect of Electric Fields Distribution around the HV Power Transmission Line Using Finite Element Method


Authors: P. Pao-La-Or, W. Ongsanthea

Abstract: This paper has proposed a mathematical model of electric fields caused by high voltage (HV) conductors of electric power transmission systems by using a set of second-order partial differential equations (PDE). This study has considered line configuration of an overhead ground wire (OHGW) the effect on electric fields emitted around a 500-kV power transmission line. Comparison among seven test cases configuration, varying height of OHGW, varying distance between two-line of OHGW and varying size of OHGW, has been illustrated. Computer-based simulation utilizing the two-dimensional finite element method (FEM) in the time harmonic mode, instructed in MATLAB programming environment with graphical representation for electric field strength has been investigated. From all test cases, the calculation line of 1.0 m above the ground level is set to investigate the electric fields acting on a human.

Keywords: Overhead Ground Wire (OHGW), Line Configuration, Electric Field, Finite Element Method (FEM), Transmission Line

Issue 4, Volume 6, October 2011

Title of the Paper:  Design and Simulation of Stand Alone Photovoltaic Systems


Authors: Salima Kebaili, Achour Betka

Abstract: This paper presents the design and simulation of a stand alone photovoltaic system. The main activities of this work purpose to establish library mathematical models for each individual component of stand alone photovoltaic system. Control strategy has been considered to achieve permanent power supply to the load via photovoltaic/battery based on the power available from the sun. The complete model was simulated under two testing including sunny and cloudy conditions.

Keywords: Renewable energy, Photovoltaic system, Lead-acid battery, Modeling, Control, Simulation

Title of the Paper:  PI, PID and Fuzzy Logic Controlled Cascaded Voltage Source Inverter based Active Filter for Power Line Conditioners


Authors: Karuppanan P., Kamalakanta Mahapatra

Abstract: This paper presents a PI, PID and Fuzzy Logic Controller (FLC) based shunt active filter for power line conditioners (PLC) to improve the power quality in the distribution network. This active power filter is implemented with current controlled cascaded multilevel voltage source inverter (VSI). It is connected at the point of common coupling for compensating harmonic and reactive power by injecting equal but opposite harmonic compensating currents. The reference current extraction is based on sensing main currents only, which require current harmonics and reactive volt-ampere compensation. The PI or PID or fuzzy logic controller is used to estimates the peak reference current by controlling the dc-bus capacitor voltage of the cascaded inverter. The cascaded multilevel inverter switching signals are derivates from triangular-sampling current controller; it gives a good dynamic performance under steady state and transient operations. The cascaded active filter system is validated through extensive simulation under steady state and transient conditions with different non-linear loads. These simulation results have been revealed that the cascaded active power filter performs perfectly in conjunction with PI or PID or FLC. A comparative assessment of these three different controllers is disclosed.

Keywords: Active Power Line Conditioners (APLC), PI and PID Controller, Fuzzy Logic Controller (FLC), Triangular-Sampling current controller, Harmonics, Power quality

Title of the Paper:  Energy Based Control Strategy for the Reduction in the Response Time of DSTACOM


Authors: Sakshi Bangia, P. R. Sharma, Maneesha Garg

Abstract: This paper studies the timely issue of response of Distribution Static Compensator when there is reduction in AC and DC loads. DSTACOM is an important device in correcting power quality problems like harmonics reduction, load balancing, reactive power compensation etc. The energy stored in its dc capacitor releases during transients to provide ride through to facilitate load shedding. .The presented algorithm evaluates the reduction in response time of dstatcom based on energy of capacitor rather than voltage. And it is compared with conventional algorithm which regulate the voltage of the capacitor, mainly depends on the values of PI parameters. It is observed that ratio of gains of proportional to integral controller is many times larger in case of new scheme introduced here .Thus the effect of sudden power loss is investigated with and without the DSTATCOM connection and concluded that response time reduces from 0.04 sec to 0.01 sec The present approach is validated through simulations using MATLAB software with its Simulink and Power System Block set (PSB) toolboxes and then graphical programming of LabVIEW software has been utilized to develop analyzer and also to monitor the results . Use of virtual instrumentation for the measurement and monitoring power system improves the performance and reliability of the system.

Keywords: DSTATCOM, transient time, voltage source converter, THD reduction, LABVIEW

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