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In deregulation, growth in electrical loads necessitates improving power delivery, while nondiscriminatory access to transmission grid is a requirement. Deregulation causes a significant rise in transactions, which requires adequate transfer capability to secure economic transactions. In sustainable power delivery, FACTS devices are deployed to enhance available transfer capability (ATC). However, the high investment cost of FACTS makes the problem formulation a multiobjective optimization: power transfer maximization and minimization of FACTS sizes. Furthermore, due to the complexity in optimizing the control variables of voltage source converter types of FACTS, often the solution results in local optima and high computational time. This paper proposes a hybrid of real power flow performance index sensitivity (∂P I) and particle swarm optimization (PI-PSO) to solve the multiobjective optimization of ATC maximization with minimum FACTS sizes using continuation power flow. ∂P I identifies some high-potential locations with enhanced ATC at minimum FACTS size to constitute the PSO's reduced search space. As ∂P I may exhibit masking effects, iterative nexponent and Newton's divided difference approaches are proposed to reduce masking. The proposed PI-PSO is implemented with a thyristor control series compensator and static synchronous series compensator for both bilateral and multilateral transactions. Results show the effectiveness of the proposed PI-PSO over PSO regarding convergence characteristics, avoidance of local optima, and superior ATC values.

SUMMARY This paper presents detail assessment of the impact of renewable energy type distributed generation operation modes on the voltage stability indices. Most of renewable distributed energy sources are capable of operating in two modes, which are constant voltage and constant power modes. Different simulation results were obtained for voltage stability index (VSI), which serves as indicator of stability. Furthermore, this study has also considered charging station (CS) as a load, that is, gradually increased at the selected bus until the system attains instability state. The persistence of the instability can lead to voltage collapse, and VSI value can give an indication of the collapse as well. In this paper, the concept of active power voltage stability index (P‐VSI) is introduced with the aim of predicting the voltage collapse as a result of incremental CS loading in the network. Based on the analysis conducted in radial networks with multiple distributed generation units, the P‐VSI gave better indication for the voltage collapse much more than reactive power voltage stability index. The analysis was conducted on 33 bus distribution system. Copyright © 2013 John Wiley & Sons, Ltd.

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This paper considered the formulation of continuous third derivative trigonometrically fitted method for the solution of oscillatory first order initial value problems using the technique of interpolation and collocation of the approximate solution by combining polynomial and trigonometric functions. Solving for the unknown parameters and substituting the results into the approximate solution yielded a continuous linear multistep method, which was evaluated at some selected grid points where two cases were considered at equal intervals to give the discrete schemes which are implemented in block form. The blocks are convergent and stable. Numerical experiments show that the methods compete favorably with existing method.This paper considered the formulation of continuous third derivative trigonometrically fitted block method for the solution of stiff and oscillatory problems. The development of the technique involved the interpolation and collocation of the approximate solution which is the combination of polynomial and trigonometric functions. Solving for the unknown parameters and substituting the results into the approximate solution yielded a continuous linear multistep method, which is evaluated at some selected grid points where two cases were considered at equal intervals to give the discrete schemes which are implemented in block form. The blocks are convergent and stable. Numerical experiments show that the methods compete favorably with existing method and efficient for the solution of stiff and oscillatory problems.