Repair strategies for minimising the risk of cascading failures in electricity networks

In this work, we develop repair strategies for simplified models of electric power grids. The goal is to gain insight into the combinatorial properties of repair problems in order to improve maintenance and restoration planning. Firstly, we consider a seriously damaged grid and try to find the set of lines that should be repaired first in order to resupply the customers as fast as possible. We analyse two abstract repair problems that are also of theoretical interest and show how to solve them approximately. Secondly, we consider a power grid during normal operation where only a few lines are not operating due to random failures. We try to find repair strategies that minimise the risk of cascading failures in such situations. We develop a blackout model in order to understand the dynamics of blackouts and propose a repair strategy. The first computational results indicate that the proposed strategy provides a good starting point for the development of further repair strategies.