A Case Study of Voltage Stability Challenges (on a Unique Utility-Scale System in a Developing African Country)

Incidents of voltage instability and voltage collapse have become increasingly common in power systems worldwide. An example of such a system could exist within the network of a developing country which although proactively managed, has historically been suspected to be at risk of voltage instability. The utility has considered both AC and DC based solutions to address the long term needs of the province and settled on an extra high voltage AC solution for the immediate future. Previous research has not meaningfully studied utility-scale networks and has largely investigated other forms of instability. This unique case study presents the synthesis of models preceding an analysis that evaluates the position of the network from a voltage stability standpoint and introduces the various proposed strengthening options that are useful for application in the case study network to improve transfer capacity and voltage stability. The solution options, costing billions of dollars (American) include extra high voltage AC reinforcements (above 400kV) and DC bipole links with various converter types.