Practical considerations for optimal conductor reinforcement and hosting capacity enhancement in radial distribution systems

Abstract

The high penetration level of distributed generation (DG) units may lead to various problems and operational limit violations in electric power distribution systems if it exceeds a particular limit known as the system’s hosting capacity (HC). In this paper, the problem of selecting the optimal conductor for a real radial distribution system in Egypt is investigated using a recent meta-heuristic algorithm, known as salp swarm optimization. First, a constrained optimization problem is introduced to minimize the combined annual cost of energy losses and the investment cost of the conductors while complying with the system voltage limits and conductor thermal capacities. The results obtained show the effectiveness of the algorithm in satisfying the objective function and constraints. However, the optimization results also show that a reduction in the size of some existing conductors should take place, although this is not allowed by the utilities because of practical reasons such as load growth, variations in loading scenarios, and the possibility of connecting DG units with uncertain penetration levels and locations. Hence, a practical feeder reinforcement approach is proposed to maintain the constraints while considering these uncertainties. Further, a novel feeder reinforcement index is proposed to assist the distribution system operators and planners to determine the feeders that first need to be reinforced. The results obtained show that the proposed reinforcement approach attains a better level of HC than can be obtained with the conventional conductor selection approach under the same testing conditions.