A critical switching flow index for transient stability assessment in smart grid topology control

Smart grid topology control makes power system more flexible and efficient. For example, it has been demonstrated that economic benefit and corrective action in contingency can be achieved by topology control. However, transient stability is a major concern in applying smart grid topology control since a potential large disturbance of line flows is involved. In this paper, a critical switching flow concept is proposed as a transient stability index to assess system transient stability associated with topology control. This new index is based on system worst scenario in offline study and thus can be used to evaluate switching plan and avoid transient instability in real time operation without online dynamic simulations. Monte Carlo based algorithm is developed to determine critical switching flow for planned system and validated in simplified WSCC 9 bus system and IEEE 24 bus reliability test system to demonstrate a potential use of the new concept.