Optimal Placement of Compensating Devices in Distribution System by Using PSO Algorithm

In a power system, power flows from generating centers to load centers. This process requires investigation, such as bus voltage profile, flow of active power (MW) and reactive power (MVar) in transmission lines, the effect of rearranging circuits and installation of regulating devices etc. , for different loading conditions. As modern power system has become more large and complex, due to great electric power demands imposed upon high voltage transmission networks, these investigations should be done with some sort of simulation of the system. FACTS have made the power systems operation more flexible and secure. They have the ability to control, in a fast and effective manner. Amongst the several FACTS controllers, the Unified Power Flow Controller (UPFC) is most effective to improve the voltage profile and reduce the power loss. In other words it can provide functional capabilities of controlling both the active and reactive power independently. Power flow studies and optimization techniques are essential tools for the safe and economic operation of large electrical systems. There are several techniques to find the location of FACTS devices. But in this thesis the optimal placement of UPFC is found using fuzzy approach as the fuzzy can be easily analyzed. The rating value of UPFC is obtained by PSO method which iteratively optimizes global best solution for different loading conditions. The proposed method is tested on the node having maximum loss reduction and poor voltage profile improvement for the various load conditions, like 85 %, normal and 110 % overloading cases. The overall improvement of the system performance using UPFC is demonstrated on IEEE 14-bus and IEEE 30-bus test systems and the results are discussed.