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Transfer Capability (transfer + capability)
Selected AbstractsApplication of dynamic rating to increase the available transfer capabilityELECTRICAL ENGINEERING IN JAPAN, Issue 4 2009Masaki Miura Abstract As the deregulated environment of power systems has spread worldwide, it is essential to operate power systems efficiently and economically. With the advance of communication technologies and sensors, so-called dynamic rating is now to be realized. Dynamic rating is a method which determines accurate ratings by utilizing real-time information such as conductor temperatures, ambient temperatures, and wind speeds. The dynamic rating is considered to increase the thermal capacities of overhead transmission lines and therefore take on importance in the deregulated electric power industry. The importance of the dynamic rating lies mainly in the area of Available Transfer Capability (ATC) improvement. In this paper, the validity of the proposed dynamic rating application is shown from the viewpoint of ATC, especially ATC with thermal constraints. In addition, the possibilities of ATC estimations using sensitivities are verified for the purpose of reducing calculation time, considering the importance of real-time simulation of ATC. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 40,47, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20537 [source] Enhanced heat transfer analysis of latent functionally thermal fluidHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 6 2004Fengwu Bai Abstract A physical model has been developed to analyze the enhanced heat transfer process of the latent functionally thermal fluid with microencapsulated phase-change material. The problem is solved by the combination of the finite difference method and the moving heat source method. The calculated results reveal that putting the phase-change microcapsules into the fluids can enhance the heat transfer capabilities of the mixture. The effects of capsule radius and concentration of particles are numerically predicted. The numerical results provide the theoretical basis for the application and design of the latent functionally thermal fluid. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(6): 383,392, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20025 [source] Application of dynamic rating to increase the available transfer capabilityELECTRICAL ENGINEERING IN JAPAN, Issue 4 2009Masaki Miura Abstract As the deregulated environment of power systems has spread worldwide, it is essential to operate power systems efficiently and economically. With the advance of communication technologies and sensors, so-called dynamic rating is now to be realized. Dynamic rating is a method which determines accurate ratings by utilizing real-time information such as conductor temperatures, ambient temperatures, and wind speeds. The dynamic rating is considered to increase the thermal capacities of overhead transmission lines and therefore take on importance in the deregulated electric power industry. The importance of the dynamic rating lies mainly in the area of Available Transfer Capability (ATC) improvement. In this paper, the validity of the proposed dynamic rating application is shown from the viewpoint of ATC, especially ATC with thermal constraints. In addition, the possibilities of ATC estimations using sensitivities are verified for the purpose of reducing calculation time, considering the importance of real-time simulation of ATC. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 40,47, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20537 [source] An efficient methodology for security assessment of power systems based on distributed optimal power flowEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2003D. Hur This paper presents an algorithm for the parallel solution of the security constrained optimal power flow (SCOPF) problem in a decentralized framework, consisting of regions, using a price-based mechanism that models each region as an economic unit. We first solve the distributed optimal power flow (OPF) problem to determine the maximum secure simultaneous transfer capability of each tie-line between adjacent regions by taking only the security constraints imposed on the tie-lines into account. In this paper, the line outage distribution factors (LODF) calculated at the current state are used to formulate the appended constraints. Once the secure transfer capability of each tie-line is determined, the intra-regional SCOPF is performed using the conventional linear programming (LP) approach. A description on the inclusion of security constraints with distributed OPF algorithm will be given, followed by the case study for Korea Electric Power System. [source] A study on the multiswing instability region using Hopf bifurcation theory considering energy thresholdIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2006Takao Tsuji Member Abstract Transient stability is treated as one of the important constraints for calculating available transfer capability (ATC), especially in Japan. Therefore, to improve the time required for ATC calculation, development of high-speed transient stability analysis is required. For this analysis, a screening method that can recognize the serious case of fault will be greatly effective to solve the problem. Many screening methods on the first swing instability are proposed these days. However, a method based on multiswing instability has not been developed and its characteristic is not understood clearly. In this paper, the relationship between the nonlinear limit cycle and the energy function of a power system is examined using the Hopf bifurcation theory. A calculation method, which gives the critical transfer capability considering multiswing instability, is proposed. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] The impact of fouling on performance evaluation of evaporative coolers and condensersINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 14 2005Bilal A. Qureshi Abstract Fouling of evaporative cooler and condenser tubes is one of the most important factors affecting their thermal performance, which reduces effectiveness and heat transfer capability with time. In this paper, the experimental data on fouling reported in the literature are used to develop a fouling model for this class of heat exchangers. The model predicts the decrease in heat transfer rate with the growth of fouling. A detailed model of evaporative coolers and condensers, in conjunction with the fouling model, is used to study the effect of fouling on the thermal performance of these heat exchangers at different air inlet wet bulb temperatures. The results demonstrate that fouling of tubes reduces gains in performance resulting from decreasing values of air inlet wet bulb temperature. It is found that the maximum decrease in effectiveness due to fouling is about 55 and 78% for the evaporative coolers and condensers, respectively, investigated in this study. For the evaporative cooler, the value of process fluid outlet temperature Tp,out varies by 0.66% only at the clean condition for the ambient wet bulb temperatures considered. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||