Modern sensitivity index-based optimal UPFC location for power quality enhancement in the Southern Cameroon interconnected grid considering the feasibility of the load flow under N-k contingency scenarios

Actual networks operate under stressful circumstances due to the rapidly increasing demand and its imbalance with generation, pushing them close to their stability limits which can lead to voltage instability and poor power quality. To fix these problems, flexible solutions with FACTS are optimally implemented. In this paper, a novel index-based method for an optimal UPFC location is proposed using the index termed Modern Stability Assessment Index (MSAI) which is comprehensively accounts for all parameters and variables of transmission lines as compared previous indices. The approach consists of identifying through MSAI computation in normal and N-k contingency operating cases the most critical line which can be the best suitable UPFC location for improving the voltage profile and maximum load-ability, minimizing power losses and damping oscillations. Additionally, a Newton-based continuation power flow N-k contingency method is implemented in the study to refine and confirm the MSAI-based selection through a congestion analysis considering only feasible cases of branch outages since unfeasible cases are negligible. Furthermore, a dynamic stability assessment is performed in both time-domain analysis and eigenvalue analysis for validating the suitable UPFC location. The study is first of all validated with IEEE-14 bus test system and practically implemented in the Southern Interconnected Grid (SIG) for enhancing its power quality in a context of generation/demand imbalance. The study is performed considering base, intermediate and peak load scenarios, respectively using Matlab shows through a comparative analysis that the line 5–6 is the most suitable one for UPFC placement. The results obtained in normal operations show an improvement of the average voltage magnitude from 0.931 p.u to 0.974, 0.982 and 0.973 p.u, respectively. The active loss reduction rate gave 18.553 %, 14.361 % and 19.616 % respectively. The maximum loading point is improved from the set (1.383, 1.548, 1.803) p.u to the set (1.544, 1.587, 2.513) p.u.