In this paper, a reliable and effective algorithm based on hybrid modified imperialist competitive algorithm (MICA) and invasive weed optimization (IWO) is proposed for solving the optimal reactive power dispatch (ORPD) problem. Without doubt, one of the simple but powerful optimization algorithms in the field of evolutionary optimization is imperialist competitive algorithm (ICA) outperforming many of the already existing stochastic and direct search global optimization techniques. The original ICA method often converges to local optima. In order to avoid this shortcoming, a new method is propose that profits from IWO method to improve local search near the global best and a series of modifications is purposed to the assimilation policy rule of ICA in order to further enhance algorithm's rate of convergence for achieving a better solution quality. The hybrid MICA-IWO method is then offered for handling ORPD problem. The introduced method is applied to ORPD problem on IEEE 30-bus, IEEE 57-bus and IEEE 118-bus power systems for testing and validation purposes. The hybrid MICA-IWO provides better results compared to the original ICA, IWO, and other methods reported in the literature as demonstrated by simulation results. 
A new hybrid algorithm for optimal reactive power dispatch problem with discrete and continuous control variables