  Installation of capacitors in distribution networks is one of the most used
procedure to compensate reactive power generated by loads and, consequently, to
reduce technical losses. So, the problem consists in identifying the optimal
placement and sizing of capacitors. This problem is known in the literature as
optimal capacitor placement problem. Neverthless, depending on the location and
size of the capacitor, it may become a harmonic source, allowing capacitor to
enter into resonance with the distribution network, causing several undesired
side effects. In this work we propose a parsimonious method to deal with the
capacitor placement problem that incorporates resonance constraints, ensuring
that every allocated capacitor will not act as a harmonic source. This proposed
algorithm is based upon a physical inspired metaheuristic known as Extremal
Optimization. The results achieved showed that this proposal has reached
significant gains when compared with other proposals that attempt repair, in a
post-optimization stage, already obtained solutions which violate resonance
constraints.
