ELECTRIC FIELD MODELING AND ANALYSIS OF EHV POWER LINE USING IMPROVED CALCULATION METHOD

This paper aims is devoted to modeling and simulation of electric field created by EHV power transmission line of 275 kV using an efficient hybrid methodology, the charge simulation method (CSM) with the Simplex Simulated Annealing (SIMPSA) algorithm in order to find the optimal position and number of fictitious charges used in CSM for an accurate calculation. Various factors that affect the electric field intensity were analyzed; it is found that the influence of the conductor sagging is clearly remarked, the maximum electric field strength at 1 m above the ground level recorded at mid-span point of the power line is 3.09 kV/m, in the proximity of the pylon, the maximum value is significantly reduced to 1.28 kV/m. The configuration type of the transmission line (single or double circuit) and the arrangements of phase conductors on double circuit pylons have a significant effect on the levels of electric field around the transmission line. For a single circuit, the triangular configuration provides the lowest maximum value of electric field. For a double circuit, the inverse phase arrangement (abc-cba) or low-reactance phasing produces the lowest maximum value of electric field. The resulting maximum electric field levels were found below the exposure values set by the ICNIRP and IRPA standards for both occupational and general public. The simulation results of electric field are compared with those obtained from the COMSOL 4.3b Multiphysics software, a fairly good agreement is found

An ellipsoidal distance-based search strategy of ants for nonlinear single and multiple response optimization problems

Various continuous ant colony optimization (CACO) strategies are proposed by researchers to resolve continuous single response optimization problems. However, no such work is reported which also verifies suitability of CACO in case of both single and multiple response situations. In addition, as per literature survey, no variant of CACO can balance simultaneously all the three important aspects of an efficient search strategy, viz, escaping local optima, balancing between intensification and diversification scheme, and handling correlated variable search space structure. In this paper, a variant of CACO, so-called 'CACO-MDS' is proposed, which attempts to address all these three aspects. CACO-MDS strategy is based on a Mahalanobis distance-based diversification, and Nelder-Mead simplex-based intensification search scheme. Mahalanobis distance-based diversification search ensures exact measure of multivariate distance for correlated structured search space. The proposed CACO-MDS strategy is verified using fourteen single and multiple response multimodal function optimization test problems. A comparative analysis of CACO-MDS, with three different metaheuristic strategies, viz, ant colony optimization in real space (ACO(R)), a variant of local-best particle swarm optimization (SPSO) and simplex-simulated annealing (SIMPSA), also indicates its superiority in most of the test situations. (C) 2012 Elsevier B.V. All rights reserved