Contingency Ranking of Nigerian 330KV Grid Network

Contingency study technique is being widely used to forecast the effect of outages such as transmission lines, failure of associated equipment in power systems etc. The prediction of the effect of contingency using off-line analysis of individual element is a boredom task as a result of the presence of large number of components within the power system. Feasibly, severe contingency conditions in power system give rise to undue abnormalities such as voltage violations and limit of active power within the system. The process of identifying where these severe contingency are present within a network is termed contingency ranking. In this study, the contingency ranking was carried out on the Nigerian 330KV grid network by sequentially computing the Overall Performance Index (OPI) which comprises the active Power Index Performance (PIP) and the Performance Index Voltage (PIV) for a single transmission line outage using Newton-Raphson Load Flow (NRLF) technique in Power World Simulator environment. The most severe contingency ranking has being carried out based on the summation of the values of these two performance indices that formed the OPI. The value of active power flow and bus voltages in both the existing and fortified Nigerian 330KV grid network were carried out with the most severe transmission line contingency analyzed simultaneously. The efficacy of this method was tested on a 40-bus model of the Nigerian 330KV network. Based on the knowledge of PIP and PIV, it can be inferred from the results that the most severe contingency in a transmission line can be identified and the resultant effect of this contingency on the remaining part of system can be studied.