This paper presents a novel hybrid algorithm combining Firefly Algorithm (FA) and Nelder Mead (NM)
simplex method for solving power system Optimal Reactive Power Dispatch (ORPD) problems. The ORPD
is a very important aspect of power system operation and is a highly nonlinear, non-convex optimization
problem, consisting of both continuous and discrete control variables. Like many other general purpose
optimization methods, the original FA often traps into local optima and in order to overcome the shortcoming,
in this paper, an efficient local search method called NM simplex subroutine is introduced in the
internal architecture of the original FA algorithm. The proposed Hybrid Firefly Algorithm (HFA) avoids
premature convergence of original FA by exploration with FA and exploitation with NM simplex. The proposed
method is applied to determine optimal settings of generator voltages, tap positions of tap changing
transformers and VAR output of shunt capacitors to optimize two different objective functions; such
as minimization of real power loss and voltage deviations. The program is developed in Matlab and the
proposed hybrid algorithm is examined on two standard IEEE test systems for solving the ORPD problems.
For validation purpose, the results obtained with the proposed approach are compared with those
obtained by other methods. It is observed that the proposed method has better convergence characteristics
and robustness compared to the original version of FA and other existing methods. It is revealed
that the proposed hybrid method is able to provide better solutions