Considering Integer Chance Constraints for Enforcing Flexible Line Flow Ratings

Abstract

Transmission line capacity ratings are often treated as a fixed nominal value; however, these ratings can be temporarily increased to a higher rating that can be leveraged when accounting for uncertainty in the system. In this paper, we introduce a chance constrained optimal power flow model to account for fluctuations in wind power generation with respect to line flow ratings. We propose a two-stage stochastic program where the optimal traditional generator dispatch is determined across wind power fluctuation scenarios. Flexible line flow ratings are incorporated into our model using integer chance constraints which limit the probability of non-nominal line capacity rating violations across all wind scenarios. We present simulation results on the RTS-GMLC test system to demonstrate the effectiveness of considering infrequent line violations on network congestion to reduce the total average wind power curtailment by 15%.