Prasanthi P. S ,Hazeena K .A
This paper describes optimal power flow based on swarm intelligence in which the power transmission loss function is used as the problem objective . Although most optimal power flow problems involve the total production cost of the entire power system, in some cases some different objective may be chosen. In this paper ,to minimize the overall power transmission losses ,four decision variables are participated . They are a)power generated from generating plants b) specified voltage magnitude at control substations c)tap positions of tap changing transformers d)reactive power injection from reactive power compensators . Swarm intelligence are well known and widely accepted as potential intelligent search methods for solving such a problem .In this paper particle swarm optimization[PSO] and improved particle swarm optimization [IPSO] are employed to solve optimal power flow problems .A 30-bus IEEE power systems are used for test .As a result , IPSO –based optimal power flow gives the best solution.