Optimal shunt capacitor sizing for reduced line loading, voltage improvement and loss reduction of distribution feeders

A simple algorithm is proposed for the optimal capacitor sizing problem of distribution systems having randomly distributed concentrated loads, nonuniform wire size, and laterals. The model presented is nonlinear and includes the power flow limit of overloaded lines. The proposed method determines the near-optimum solution for the capacitor sizing problem. The method uses a quadratic programming approach. A quadratic objective function and linear constraint inequalities are used in conjunction with linear line loading inequalities. The objective function and the voltage inequalities are derived by using the bus impedance frame of reference. The derivation of the line loading inequalities is based on the distribution factors. Test results are given