Assuring transient stability in the smart grid

With unprecedented capabilities for monitoring system operating conditions based on synchronized sub-second measurements and providing quasi-continuous control signals throughout the grid, the smart grid offers the potential to increase all voltage, transient and dynamic (small signal) stability limits to a level above the relevant thermal limits. With stability thus assured, the smart grid can ultimately become as flexible as the internet. This paper presents a strategy for assuring transient stability in the smart grid. The proposed closed-loop control scheme creates a stable operating point in locations where the open loop system (i.e., the system without the controller) would be unstable. Simulation results for a simple system are presented to illustrate the capabilities of the scheme. The stable operating region of the system can be expanded until the onset of “managed chaos” where a sequence of ephemeral equilibria can be created until a stable equilibrium is reached.