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  • Author: Z.Y. Yang, x
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A new tree structure called the two-level computation tree model is proposed for real time dynamic simulation of large-scale power systems. The features of the computation tree method are that the root node of the tree corresponds to a disconnected linear network, which is easy to be dealt with, and the tree leaf-nodes represent the partitioned subsystems. In the process of trajectory simulation, the correction factors of Newton type iteration are computed through a tree traversal procedure. One advantage of the new method is that the computation tasks for all subsystems can be carried out simultaneously using any parallel computation facilities. Case studies on the 10-generator New England test power system and on a representation of Northeast China power system verify the accuracy and validate the potential application of the proposed method in the real time contingency simulation for realistic large-scale power system.

Molar volume and conductivity measurements have been carried out at 298.15 K for cetylpydinium chloride (CPC) + H2O and CPC + β-cyclodextrin (β-CD) + H2O systems. The apparent critical micelle concentrations, the dissociation degree of the micelle, the hydrophobic contribution of the transfer free energy for the hydrocarbon chain of CPC, the standard partial molar volumes of CPC in aqueous β-CD solutions and the stoichiometry for the inclusion complex of CPC with β-CD have been determined. The influence of β-CD and its complex on the micellization processes of CPC is analyzed. It is shown that β-CD partly screened the hydrophobic hydrocarbon chain of CPC molecules from contact with the surrounding medium, and retarded the formation of CPC micelles in a certain extent. The thermodynamic activity of CPC is decreased due to the formation of complex. The β-CD and its complexes do not participate the formation of micelles of CPC, and the complex has no effect on the micelle properties once the micelles are formed. The number of CH2 groups entered the cavity of β-CD was calculated based on a simple model proposed by Gonzalez-Gaitano et al. The result suggests that β-CD forms strong complex with CPC, and the stoichiometry is found to be 1 : 1 at very low concentration of β-CD and 1 : 1 and 2 : 1 complexes coexist at higher concentrations of β-CD. This supports our conductivity results.