On the Use of Evolutionary Algorithms for Reactive Power Compensation in Electrical Distribution Networks – Experiments on a Case Study

In the electrical distribution network, reactive power compensation aims at guarantying an efficient delivery of active power to loads, releasing system capacity, reducing system losses, and improving system power factor and bus voltage profile. The achievement of these aims depends on the sizing and location of shunt capacitors (sources of reactive power). Operational, economical and quality of service objectives must be weighed by decision-makers / planning engineers to select acceptable solutions having in mind their practical implementation. Multi-objective models enable to grasp the conflicting nature of the objectives and the tradeoffs to be made in order to identify satisfactory compromise solutions by providing a basis to rationalize the comparison between non-dominated solutions. The problem of optimal capacitor placement in radial electrical distribution systems is formulated considering two objective functions: minimizing capacitor installation cost and minimizing system losses. Constraints are related with requirements of acceptable node voltage profile (quality of service), power flow (physical laws in electrical networks), and impossibility