Performance of AC and DC based transmission switching heuristics on a large-scale polish system

Optimal transmission switching (OTS) has demonstrated benefits both in terms of reliability and cost savings for bulk power systems. OTS is a mixed-integer program (MIP) with binary variables representing the status of the transmission elements. Due to the computational complexity of this MIP, implementation of OTS is limited. Therefore, different heuristics have been proposed to find good, suboptimal solutions fast. The heuristics are often tested on small test cases with restricted analysis on actual systems. This work tests two of the recently developed fast heuristics on the Polish system to show their performance. The results suggest that the best solutions are among the top twenty candidates identified by the heuristics if they are based on the ACOPF solution. If the heuristics are calculated based on the DCOPF solution, the performance may be poor. The correlation between estimated benefits and actual benefits is not very promising in either of the cases.