Revealing the Impact of Multiple Solutions in DCOPF on the Risk Assessment of Line Cascading Failure in OPA Model

Cascading failure is one of the most damaging events to power systems. To mitigate the risk, it is essential to first evaluate the risk and then take corresponding protective measures. However, the issue of multiple solutions in DCOPF, which is a tool used in the existing OPA risk assessment models and a linear programming (LP) problem, has not been considered. In this letter, we show that the risk may be seriously under-estimated if we do not consider the existence of multiple solutions. The risk is evaluated by generating two dispatch plans based on a bilevel mixed integer linear programming (MILP) model for DCOPF. The solution to the bilevel MILP model is obtained by solving one LP and one MILP. Simulation results based on the IEEE 118-bus and 300-bus systems demonstrate the impact of multiple solutions in DCOPF and effectiveness of the proposed approach.