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This paper presents a refinement in the residual resistance formulation used in pollution flashover model. The proposed study focused on the residual resistance calculation of the AR or open model which used the expression of the insulator factor form. The proposed modification takes into account the non-uniformity of the current density distribution inducted by the open model which is increased by the presence of the arc root at the pollution surface. A correction factor was determined based on experimental and numerical investigations. The numerical simulations confirm that the constriction and the distribution of the current lines along the open model have a significant influence on the residual resistance calculation. The proposed corrected residual resistance formulation was then implemented in a dynamic mathematical model in order to determine the critical flashover voltage (FOV) of different cap-and-pin insulators for different pollution layer levels. The results obtained with the proposed flashover model and its corrected resistance formulation show a very good agreement with the theoretical and experimental results obtained from the literature. This validates the propose refinement of the residual resistance dedicated to polluted flashover model and provide a powerful tool for insulator dimensioning.

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.

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This study proposes a three‐dimensional (3D) quasi‐static modelling of the electric field produced by high voltage (HV) overhead power lines using charge simulation method combined with intelligent optimisation algorithms, such as particle swarm optimisation, genetic algorithm and grey Wolf optimiser (GWO), to find the optimal values of parameters for an accurate calculation. Results show that the GWO works better than other algorithms. Several parameters affecting the electric field have been studied; it is observed that taking into account the effect of the exact catenary curve of the power line conductors is much more interesting particularly at the mid‐span level where the electric field becomes very significant. According to these values, the limits set by the International Commission on Non‐Ionising Radiation Protection guidelines for electric field strength are met for occupational and public exposure. The simulation results are compared with those obtained by the 3D Integration method, a fairly good agreement is found. To confirm the performance and effectiveness of the proposed method, the results obtained are also verified with measurement values available in the literature, a good similarity is achieved.