This paper proposes transmission line capacity enhancement with optimal location and sizing of UPFC on IEEE 14-bus network. This is necessary because of the increase in load growth with every passing day without an equivalent increase of line capacity which has brought many power systems closer to their stability limit. The dynamic and practical application of this proposed method is achieved by increasing linearly, the loading factor (λ) from 1.25 to 1.50 of the base case value of 1.0 and then, its effect is investigated. In each of the increment, the power flow result is obtained using Newton-Raphson method, while the optimal location and sizing of UPFC are done using Grey Wolf Optimization (GWO) technique. The voltage deviation before and after the installation of the FACTS device is also studied at each load variation. This approach will help the bulk dispatcher of power to plan ahead so as to meet and supply the ever-growing in the demand for adequate and reliable power system as a result of population growth, improved living standards and technological advancement. The efficacy of the proposed method is verified on a standard IEEE 14-bus system. The simulation results show the effectiveness and suitable performance of the proposed methodology at enhancing transmission capacity and deferring or eliminating for transmission line upgrading.

The application of grey wolf optimization technique for multiple FACTS placement is presented in this paper for the reduction of total system losses and minimization of voltage deviation via optimal placement of Flexible AC Transmission System (FACTS) device. Grey wolf optimization (GWO) technique is inspired by social hierarchy and hunting behaviour of wolves and offers a right balance between exploration and exploitation during the search for global optimal. Series-shunt FACTS device; unified power flow controller (UPFC) is considered as a formidable device that can provides an alternative option for the flexible controllability and improvement of power transfer capability of a transmission lines. The analyses were conducted by increasing the number of UPFC in the network in order to evaluate the optimal number of FACTS devices that would give the least loss under maximum loading and contingency conditions. The efficacy of this proposed technique is demonstrated on 31-bus, 330 kV Nigeria National Grid (NNG) using MATLAB environment. The results show that optimal placement of FACTS device along with optimization technique provides a promising solution to the high power loss and voltage deviation bedevilling Nigeria National Grid.