Skip to main navigation menu Skip to main content Skip to site footer


CJET: VOL. 4 NO. 2, DEC. 2020

Load-ability Analysis during Contingency with Unified Power Flow Controller Using Grey Wolf Optimization Technique

  • Yusuf Samuel Sunday
  • Okorie Patrick Ubeh
  • Abubakar Adamu Saidu
  • Momoh Illiasu Onimisi
  • Jimoh Boyi
January 18, 2021


Voltage stability enhancement with optimal placement of a unified power flow controller considering load-ability analysis is investigated in this paper. It is essential, because when voltage instability is left unattended, it leads to voltage collapse and, consequently, in a partial or total blackout of the whole network resulting from cascading effect. The optimization process is achieved by increasing the percentage load demand index to the maximum load-ability and under single contingency. This method will be of great benefits to bulk dispatcher of power to plan ahead of how to wheel and deliver power to the end-users during both normal and contingency conditions at the least cost and time. A grey wolf optimization technique is utilised to find the optimal location and sizing of UPFC on the network. The line’s voltage stability and load margin are then evaluated with and without UPFC under different loading conditions using optimal power flow technique. The approach’s effectiveness is carried out on 31-bus, 330kV Nigeria National Grid (NNG) based on two scenarios: load-ability analysis under maximum loading of the network and load-ability analysis under single contingency. The results show that power can be transmitted to meet the growing energy demand over an existing network during normal and contingency conditions without violating voltage stability by making use of the proposed method in this paper