In this paper, a methodology is presented for the optimal allocation of capacitor banks in distribution systems with the objective of minimizing the total cost of investment and operation. The operation cost refers to the system energy loss in a six-month horizon. In addition, scenarios were considered with and without the presence of soft open points, devices that can control the reactive power in the electrical grid, in order to evaluate the impact of these equipment in the operation. The methodology is based on a meta-heuristic called the integer whale optimization algorithm, which consists of an adaptation of the whale optimization algorithm, combined with a non-linear power flow used exclusively to calculate the power loss, considering daily load curves. The tests were performed on a widely known system in literature of 33 buses. The results demonstrate the effectiveness of the use of soft open points for the system operation and the applicability of the proposed methodology in the distribution system planning.