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Volume 6 ~ Issue 10

 

 


Volume 6~ Issue 10

Research Article  open access
The effect of reduced pressure ac etylene plasma treatment on physical characteristics of carbon electrodes
Zydrunas Kavaliauskas || Vitas Valincius || Mindaugas Milieska|| Liutauras Marcinauskas
Lithuania
Research Inventy: International Journal of Engineering & Science , Volume 6 ~ Issue 10 (November 2016)

Abstract

The capacitors are increasingly being used as energy storage devicesin various power systems. The scientists of the world are tryingto maximize the electrical capacity of the supercapacitors. To achieve this purpose, numerous method sare used: the surface activation of electrodes, the surface etching using the electronbeam, the electrode etching with variousgasplasma, etc. The purpose of this work is toresearch how the properties of carbon electrodes depend on the plasma parameters at whichtheywere formed. The largest surface area ofcarbonelectrodeof47.25m2/gis obtainedat 15 ofAr/C2H2gasratio. Meanwhile, theSEMimages show that the disruption of structures with low bond energies and the formation of new onesare taking place when the carbon electrodes are etched at acetylene plasma and placed on carbon electrode. The measurements of capacitance showthat capacitors with affectedelectrodes have about10-15% highercapacity than those not treated with acetyleneplasma.

KEY WORD: plasma; voltage; temperature.


Research Article  open access
Reliability Evaluation of Riyadh System Incorporating Renewable Generation
Omar I. Asiri|| Yasir A. Alturki|| Mamdooh S. Al-Saud|| Mohamed A. El-kady
Saudi Arabia
Research Inventy: International Journal of Engineering & Science , Volume 6 ~ Issue 10 (November 2016)

Abstract

In this paper, the experience of Saudi Electricity Company (SEC) in analyzing the generation adequacy for Year 2013 is presented. This analysis is conducted by calculating several reliability indices for Riyadh system hourly load during all four seasonal periods. The reliability indices are gauged against the international utility practice. SEC also plans to introduce renewable energy into the network in order to secure the environmental standards and reduce fuel costs of conventional generation. Thus, the reliability improvement due to different integration levels of Solar and Wind generating sources has also been investigated. The capacity value provided by these variable renewable energy sources (VERs) to reliably meet the system load has been calculated using effective load carrying capability (ELCC) technique with a loss of load expectancy metric.

KEY WORD: Reliability indices, generation adequacy, Solar and Wind systems,capacity outage table.


Research Article  open access
Impacts of Demand Side Management on System Reliability Evaluation
Majed I. Asiri|| Mamdooh S. Al-Saud|| Yasir A. Alturki|| Mohamed A. Elkady
Saudi Arabia
Research Inventy: International Journal of Engineering & Science , Volume 6 ~ Issue 10 (November 2016)

Abstract

Electricity demand in Saudi Arabia is steadily increasing as electrical loads grows at a rate of about 7% per year, this represents a high rate by all standards, and largely due to population growth, as well as due to government subsidies which may lead to prices much lower than actual production cost. This growth represents a challenge that requires Saudi Electricity Company (SEC) to invest huge amounts of money every year, for the construction of additional generation capacity along with the reinforcement of transmission network to meet the consumption growth.Also the demand varies frequently throughout the day, causing a waste of a large part of the energy. SEC believes the optimum solution lies in altering the load shape in order to have a better balance between customer's consumption and SEC's generation, This paper describes the method for improving the power system reliability by shifting the portion of peak load to off-peak periods This load management scheme can be achieved by lifting the generation during off peak periods and utilizing the stored energy during peak periods. A hybrid set up involving solar and wind energy along with batteries can also be used to store energy and utilize it during peak periods.

KEY WORD: Index Terms- Load management, renewable energy, and system reliability indices


Research Article  open access
Choice of Numerical Integration Method for Wind Time History Analysis of Tall Buildings
Mohammad Bhuiyan|| Roberto Leon
USA
Research Inventy: International Journal of Engineering & Science , Volume 6 ~ Issue 10 (November 2016)

Abstract

Wind tunnel tests are being performed routinely around the world for designing tall buildings but the advent of powerful computational tools will make time-history analysis for wind more common in near future. As the duration of wind storms ranges from tens of minutes to hours while earthquake durations are typically less than a three to four minutes, the choice of a time step size (Δt) for wind studies needs to be much larger both to reduce the computational time and to save disk space. As the error in any numerical solution of the equation of motion is dependent on step size (Δt), careful investigations on the choice of numerical integration methods for wind analyses are necessary. From a wide variety of integration methods available, it was decided to investigate three methods that seem appropriate for 3D-time history analysis of tall buildings for wind. These are modal time history analysis, the Hilber-Hughes-Taylor (HHT) method or α-method with α=-
0.1, and the Newmark method with β=0.25 and γ=0.5 ( i.e., trapezoidal rule). SAP2000, a common structural analysis software tool, and a 64-story structure are used to conduct all the analyses in this paper. A boundary layer wind tunnel (BLWT) pressure time history measured at 120 locations around the building envelope of a similar structure is used for the analyses. Analyses performed with both the HHT and Newmark-method considering P-delta effects show that second order effects have a considerable impact on both displacement and acceleration response. This result shows that it is necessary to account P-delta effect for wind analysis of tall buildings. As the direct integration time history analysis required very large computation times and very large computer physical memory for a wind duration of hours, a modal analysis with reduced stiffness is considered as a good alternative. For that purpose, a non-linear static analysis of the structure with a load combination of 1.0D + 1.0L is performed in SAP2000 and the reduced stiffness of the structure after the analysis is used to conduct an eigenvalue analysis to extract the mode shapes and frequencies of this structure. Then the first 20-
modes are used to perform a modal time history analysis for wind load. The result shows that the responses from modal analysis with "20-mode (reduced stiffness)" are comparable with that from the P-Δ analyses of Newmark-method.

KEY WORD: Tall Building, Time-history analysis, Wind tunnel.


Research Article  open access
Transient flow analysis for horizontal axial upper-wind turbine
Gwo-Chung Tsai || Wei-Shiue Li
Taiwan
Research Inventy: International Journal of Engineering & Science , Volume 6 ~ Issue 10 (November 2016)

Abstract

This study is to carry out a transient flow field analysis on the condition that the wind turbine is working to generate turbine, the wind turbine operating conditions change over time, Purpose of this study is try to find out the rule from the wind turbine changing over time . In transient analysis, the wind velocity on inlet boundary and rotation speed in the rotor field will change over time, and an analytical process is provided that can be used for future reference. At present, the wind turbine model is designed on the concept of upwind horizontal axis type. The computer engineering software GH Bladed is used to obtain the relationship between the rotor velocity and the wind turbine. Then the ANSYS engineering software is used to calculate the stress and strain distribution in the blades over time. From the analytical result, the relationship between the stress distribution in the blades and the rotor velocity is got to be used as a reference for future wind turbine structural optimization.

KEY WORD: transient flow field analysis, upwind wind turbine, horizontal axis, ANSYS.