Optimization of electric field screening effect under EHV overhead transmission lines using hybrid computing CSM-GOA paradigm

In this paper, a quasi-static modelling for assessment and screening of electric field generated by an EHV overhead alternating current (AC) transmission line installed adjacent to a sensitive area is treated, based on an improved computing paradigm that is a hybrid charge simulation method (CSM) and grasshopper optimization algorithm (GOA). The intelligent algorithm is applied to adjust the optimal number and position of simulating changes to improve the accuracy of the electric field calculation method, as well as to determine the geometric coordinates of the passive and active shielding conductors and to evaluate the voltage to be injected in the case of active shielding; to significantly reduce the electric field in the area to be protected. The results showed that when the sag effect is considered, the electric field value at mid-span is higher than in the vicinity of the suspension pylons, the average value can be considered approximately equal to the electric field value, when the sag effect is neglected. The performance of screening effect shows that active shielding is more reliable than passive shielding for electric field attenuation. An undesirable side effect for transmission line energy efficiency arises from the shielding wires which consist of the increase in the maximum gradient of the electric field and the energy losses by Corona phenomena on the surface of the conductors. The methodology adopted performance is in perfect agreement with the results reported in the CIGRE (International Council on Large Electric Systems) standard.