A penalty approach for NIPM based optimal reactive power flow including discrete variables

This paper deals with the application of a nonlinear interior point method (NIPM) to optimal reactive power flow (ORPF) using rounding penalty functions. The applied penalty is in the form of a cosine function and is included to harmonize with the barrier functions for discrete control variables in power system optimization problems. The procedure and formulation for the discrete ORPF problem to handle the discrete control variables using the penalty functions are presented. Test results with 14-bus test systems show the applicability of the proposed algorithm.