Application of Short Circuit Current Analysis as A Predictive Tool Against Grid Collapse in Nigeria Power System

The 330 kV power network in Nigeria experiences several major problems such as voltage instability, aged and dilapidated transmission facilities, and total power network collapse. In assessing voltage instability, the orthodox approach uses load flows and the continuous power flow technique. Though reliable, this approach is expensive and not very applicable in real time conditions. Short circuit current assessment is therefore proposed as an effective method of predicting and preventing voltage instability in the Nigerian power system. This is based on analyzing the relationship that exists among short circuit ratio (SCR), impedance level, and maximum power transfer capability. Through this process, short circuit boundaries which determine voltage vulnerable points are established. Short circuit current assessment was carried out using PSS/E software under normal and contingency states for Nigeria's power network. Findings reveal that buses with relatively lower short circuit current experience exponential reduction in statutory voltage levels. As a result, short circuit current monitoring becomes an instant indicator for corrective measures to be implemented.