Improving the Resilience of Power Grids in the Face of Focused Attacks Using the Contingency Analysis

In today's societies, the power systems despite their vast developments as critical infrastructures (CI), are exposed to numerous natural and unnatural threats. In the past, power grids were designed only to withstand typical events which would have predictable probabilities. However, nowadays events with low probabilities and high effects are considered a major challenge. Power grids are expected to have the necessary flexibility in the face of such events and should not be disrupted quickly. This demonstrates the concept of resilience. In this article the resilience enhancement strategies, and in particular, the undergrounding as the best solution, are examined considering focused physical attacks. Taking budget constraints into account, the proposed algorithm determines the priorities of lines and buses to be undergrounded. This algorithm considers two approaches of the contingency analysis, namely the experts views and the index of load loss, in order to get the best choices for undergrounding. It should be noted that in this paper the static status of the grid is considered. Finally, the proposed method is implemented on the IEEE 39-bus test grid using Digsilent software, and the results are presented and discussed to evaluate the capabilities of the proposed method.