Sparse estimation based external system line outage detection

In power systems, accurate detection of line outages is important for the reliable and secure operation. Under normal system conditions, with all measurements available, state estimation provides system wide awareness to the operators. However, when a subset of measurements is lost, the system can split into two subsystems: observable (internal) and unobservable (external). The state estimation cannot be carried out for the unobservable portion of the system until the measurements can be recovered. In this paper, we present a computationally efficient external line outage detection algorithm that uses only the internal bus phase angles and the pre-contingency system topology of the system. The main contribution of the proposed method is that it introduces a post-detection verification step to eliminate false positives. Both DC and AC simulations are performed using an IEEE 14-bus system to confirm the effectiveness of the proposed outage detection algorithm.