This work shows the use of the operating region of a D-STATCOM based on multilevel current-source inverters to define its operating point and its LC filter. A multilevel current-source D-STATCOM model is defined to compute its operating region and obtain a relation between reactive power compensation and the device power losses. Using this relationship the losses costs of the reactive power compensation is computed and used to define a methodology to get an operating point and design the LC as a function of the desired cost for nominal power compensation. The methodology is tested in the design of a 125kVA/380V distribution grid, where simulation results corroborate the analysis, including changes from one operating point to another, in open loop, to show the compensation capabilities, the power topology effort and the grid mains variables with compensation.