Trade-off methods for capacitor placement in unbalanced distribution systems

In this paper, the problem of the optimal allocation and sizing of capacitors in unbalanced distribution systems is formulated as a multi-objective optimization problem. Financial factors as well as technical issues are considered among the objectives. The costs include, in the most general case, at least initial investment cost and Joule losses costs; the other objective functions link the capacitor placement to power quality indices, such as fundamental voltage profile, harmonic distortion and unbalances. The multi-objective problem is solved by means of trade-off methods, that are valuable tools for distribution engineers that have to select the best-compromise solution. A case study referred to the IEEE 13-node test feeder is presented and discussed