A MIQP FORMULATION FOR OPTIMAL OPERATION OF SWITCHABLE CAPACITORS IN POWER DISTRIBUTION GRIDS WITH DISTRIBUTED GENERATION

Abstract

The growing penetration of on-site generating units and the rapid growth of electricity demand could result in increased power loss. This research describes a mixed-integer quadratic programming (MIQP) based formulation to determine the optimal operation of switchable capacitors with the aim of minimizing the total power losses in power distribution systems. The proposed formulation encompasses constraints such as power flow equations, thermal limits of branches, and nodal voltage magnitude bounds. The developed MIQP formulation is converted from a mixed-integer nonlinear programming (MINLP) model by a piecewise linearization approach. The globally optimal outcome of the proposed MIQP model is calculated by utilizing the CPLEX commercial solver within the GAMS programming language. The evaluation of this MIQP formulation is implemented using an IEEE 33-node distribution network with different scenarios of load consumption power. The calculation results reveal that optimal control of switchable capacitors makes a significant contribution to the reduction of the overall power losses and enhancement of voltage profile in distribution systems. Moreover, the calculation time of the proposed MIQP model is significantly lower than that of the MINLP formulation.