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Busbar Protection Scheme Based on Alienation Coefficients for Current Signals
Issue:
Volume 3, Issue 3, June 2014
Pages:
103-115
Received:
20 April 2014
Accepted:
8 May 2014
Published:
20 May 2014
Abstract: In modern digital power system protection systems, statistical coefficients technique is recently used for fault analysis. An alienation technique is developed for busbar protection against all ten types of shunt faults, which may locate in busbar protection zone, under different loading levels, fault resistances and fault inception angle. It does not need any extra equipment as it depends only on the three-line currents measurements, of all feeders connected to the protected busbar, which are mostly available at the relay location. It is able to perform fault detection, fault confirmation, faulty phase selection and determine the fault location in about a half-cycle period. Thus, the alienation technique is well suited for implementation in digital protection schemes. The technique is efficient to detect current transformer saturation conditions without needing any additional algorithm. The effects of DC components and harmonics are eliminated with estimation of alienation coefficients. The proposed methodology is applied for a part of 500 KV Egyptian network. Alternative transient program (ATP) and MATLAB package are used to implement the proposed technique.
Abstract: In modern digital power system protection systems, statistical coefficients technique is recently used for fault analysis. An alienation technique is developed for busbar protection against all ten types of shunt faults, which may locate in busbar protection zone, under different loading levels, fault resistances and fault inception angle. It does ...
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A New Scheme Based on Correlation Technique for Generator Stator Fault Detection-Part І
R. Abd Allah,
S. M. Mohamed,
E. H. Shehab-Eldin,
M. E. MASOUD
Issue:
Volume 3, Issue 3, June 2014
Pages:
116-124
Received:
20 April 2014
Accepted:
13 May 2014
Published:
30 May 2014
Abstract: In modern digital protection systems, a correlation technique is recently used for study and analysis. In this paper, a correlation technique is developed for fault detection, classification and direction discrimination. The proposed technique is able accurately to identify the different types of faults that may occur in synchronous generator stator winding. Three line-current measurements are required for both generator sides. The suggested technique performs the fault classification task within half-cycle. Thus, the algorithm is well suited for implementation in a digital generator protection scheme. The used technique is applied for El-kuriemat power station unit that produces 320 MVA. Alternative transient program (ATP) and MATLAB programs are used to implement the proposed technique in this paper.
Abstract: In modern digital protection systems, a correlation technique is recently used for study and analysis. In this paper, a correlation technique is developed for fault detection, classification and direction discrimination. The proposed technique is able accurately to identify the different types of faults that may occur in synchronous generator stato...
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Reduced Losses in PV Converters by Modulation of the DC Link Voltage
Alex Van den Bossche,
Jean Marie Vianney Bikorimana,
Firgan Feradov
Issue:
Volume 3, Issue 3, June 2014
Pages:
125-131
Received:
17 April 2014
Accepted:
27 May 2014
Published:
30 May 2014
Abstract: The efficiency of PV systems has improved by the fact that the researchers have used different techniques to increase their technical capabilities. This paper aims to present how the PV converter losses can be reduced by employing a polypropylene capacitor in the DC link and to modulate that DC voltage. This modification leads to problems with controllability and stability. In order to solve them two current control methods are presented - constant off time and a PWM type with second order high pass filter DC-link feedback. PV converters that utilize polypropylene capacitors do have lower losses and have lower cost. The PV converter simulation in Matlab SimulinkTM and lab experiment, presented in this paper, are based on a three-phase bridge APTGF50X60T3G, used to combine a step-up/step down and H-bridge in one package.
Abstract: The efficiency of PV systems has improved by the fact that the researchers have used different techniques to increase their technical capabilities. This paper aims to present how the PV converter losses can be reduced by employing a polypropylene capacitor in the DC link and to modulate that DC voltage. This modification leads to problems with cont...
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Seasonal Peak Characteristic Comparison Analysis by Hourly Electricity Demand Model
Yusri Syam Akil,
Hajime Miyauchi
Issue:
Volume 3, Issue 3, June 2014
Pages:
132-138
Received:
9 May 2014
Accepted:
29 May 2014
Published:
10 June 2014
Abstract: As driver variables may influence more than one area of electricity demand, knowing typical effect of the variables on certain demand areas is important. Utilities can use the information of managing power systems to meet electricity demand for different areas more effective. Based on the regression analysis approach, this study presents a peak demand characteristics comparison between Japanese residential and commercial areas in seasonal level by composing hourly electricity demand model for each area. Besides, a representative hour for off-peak demands is also analyzed. Similar variables (temperature, humidity, wind speed, and holidays) are applied to explain peak and off-peak of summer, autumn, winter, and spring in both areas. Results indicate key drivers for peak and off-peak demands are not same in the certain seasons for both areas. Obtained key variables tend to affect stronger peaks and off-peaks for residential than for commercial area in four observed seasons.
Abstract: As driver variables may influence more than one area of electricity demand, knowing typical effect of the variables on certain demand areas is important. Utilities can use the information of managing power systems to meet electricity demand for different areas more effective. Based on the regression analysis approach, this study presents a peak dem...
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Analytical Investigations of Thermo-Geometrical Parameters Effects on Heat Transfer and Performance of Longitudinal Radiating Fin
Bayo Yemisi Ogunmola,
Gbeminiyi Sobamowo
Issue:
Volume 3, Issue 3, June 2014
Pages:
139-146
Received:
7 May 2014
Accepted:
15 May 2014
Published:
20 June 2014
Abstract: In this work, analytical models are developed for determining temperature distribution, heat transfer and the efficiency of radiating fin. The developed models are used to investigate the effects of various thermo-geometric properties on the temperature distribution and consequently on the performance of the radiating fin. The effects of fin tip conditions on the thermal performance of the fin are also examined. From the results, it is shown that the variation in the thermo-geometric parameters (fin tip Biot number, modified Biot number and efficiency) of the fin has pronounced effects on the temperature distribution and consequently on the performance of the fin especially when a large temperature difference exists between the prime surface and the environment. The results obtained in this study serve as basis for determining the level of accuracy of any other approximation method use in the analysis of the problem and also, it could be used to improve the design of radiating fin in heat transfer equipment.
Abstract: In this work, analytical models are developed for determining temperature distribution, heat transfer and the efficiency of radiating fin. The developed models are used to investigate the effects of various thermo-geometric properties on the temperature distribution and consequently on the performance of the radiating fin. The effects of fin tip co...
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A New Scheme Based on Correlation Technique for Generator Stator Fault Detection-Part π
R. Abd Allah,
S. M. Mohamed,
E. H. Shehab-Eldin,
M. E. Masoud
Issue:
Volume 3, Issue 3, June 2014
Pages:
147-153
Received:
20 April 2014
Accepted:
8 May 2014
Published:
10 July 2014
Abstract: An experimental model for the synchronous generator was implemented and windings tapped at different positions to obtain faults at different locations on the stator windings. LABVIEW was used to obtain an interface between the experimental model and the suggested digital relay; whereas the proposed algorithm is executed using MATLAB. The obtained experimental results showed a great similarity with those obtained from ATP-EMTP simulation and that indicated the capability of safe application of the new auto/cross correlation protection technique.
Abstract: An experimental model for the synchronous generator was implemented and windings tapped at different positions to obtain faults at different locations on the stator windings. LABVIEW was used to obtain an interface between the experimental model and the suggested digital relay; whereas the proposed algorithm is executed using MATLAB. The obtained e...
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The Analysis of Diesel Engine Intake System Simulation Based on Multivariate Joint Optimization
REN Hongjuan,
Wang Huilong,
LUO Yiping
Issue:
Volume 3, Issue 3, June 2014
Pages:
154-157
Received:
7 May 2014
Accepted:
20 May 2014
Published:
10 July 2014
Abstract: The paper was based on multivariable joint optimization. It established an optimization process of diesel engine intake system. The simulation model was built in AVL-BOOST and tested by experiments. As the design variables of intake system parameters (diameter and length of intake duct and intake manifold) were used to orthogonal test. Through the calculation of the engine performance optimization, the sum of paper was the impact of key parameters of the intake system on the performance of engine, and the influence of variable parameters on the volumetric efficiency of engine. These works provided a theoretical reference of intake system optimization design.
Abstract: The paper was based on multivariable joint optimization. It established an optimization process of diesel engine intake system. The simulation model was built in AVL-BOOST and tested by experiments. As the design variables of intake system parameters (diameter and length of intake duct and intake manifold) were used to orthogonal test. Through the ...
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The Application Status and Prospects of Vibro Ripper
Wang Kaile,
Yang Guoping,
Hu Kaijun,
Wang Kai,
Cao Guojun
Issue:
Volume 3, Issue 3, June 2014
Pages:
158-161
Received:
19 June 2014
Accepted:
3 July 2014
Published:
10 July 2014
Abstract: Vibro ripper is a new pattern of breaker hammer, The hydraulic pump is the power source, Hydraulic oil as the working medium. By the hydraulic energy into mechanical energy of actuator mechanism, It works by the impact force, Vibro ripper combined with the use of excavators. The crushing effect is amazing. This paper introduced the domestic of research and development status of the vibro ripper home and abroad. The key technology of the vibro ripper were summarized and analyzed. Put forward the development trend base on these aspect.
Abstract: Vibro ripper is a new pattern of breaker hammer, The hydraulic pump is the power source, Hydraulic oil as the working medium. By the hydraulic energy into mechanical energy of actuator mechanism, It works by the impact force, Vibro ripper combined with the use of excavators. The crushing effect is amazing. This paper introduced the domestic of rese...
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