Optimal conversion of transmission lines using HPO method considering power quality indices

Nowadays, given the ever-increasing growth of the industry, the optimal use of electrical energy is of particular importance. On the other hand, due to the fact that the increase in the voltage of electric energy transmission lines is almost saturated to increase the power transmission capacity, the need to find new solutions for this purpose is very necessary. One of the solutions that is considered today for optimal utilization of electrical power sources is multi-phase transmission networks. Multiphase transmission networks are networks of 6, 9 and 12 phases, which are among the preferred 6-phase networks and are known as a useful way to increase transmission power against increasing energy demand. The most important factors affecting the choice of optimal conversion (suitable alternative) of transmission lines can be the system losses and the acceptable range for the voltage of all the bus. But since there are a lot of nonlinear loads in the power systems, and this generates harmonics across the network, it is necessary to consider network harmonics and power quality indices. In this paper, a method is proposed to find the best arrangement of lines with the aim of optimizing power quality indices, which is carried out using multi-objective optimization based on non-post ranking (NSGA_II). The results have been performed on a 400 kV network in south of Iran.