Automated Two-stage Conversion of Hourly Optimal DC Flow Solution to AC Power Flow

Conversion of hourly dispatch cases derived using DC optimal power flow (DCOPF) to AC power flow (ACPF) case is often challenging and requires arduous human analysis and intervention. This paper proposes an automated two-stage approach to solve ACPF formulated from DCOPF dispatch cases. The first stage involved the use of the conventional Newton Raphson method to solve the ACPF from flat start, then ACPF cases that are unsolvable in the first stage are subjected to a hot-starting incremental method, based on homotopy continuation, in the second stage. Critical tasks such as the addition of reactive power compensation and tuning of voltage setpoints that typically require human intervention were automated using a criteria-based selection method and optimal power flow respectively. Two datasets with hourly dispatches for the 243-bus reduced WECC system were used to test the proposed method. The algorithm was able to convert 100% of the first set of dispatch cases to solved ACPF cases. In the second dataset with suspect dispatch cases to represent an extreme conversion scenario, the algorithm created solved ACPF cases that satisfied a defined success criterion for 77.8% of the dispatch cases. The average run time for the hot-starting algorithm to create a solved ACPF case for a dispatch was less than 1 minute for the reduced WECC system.