Analysis of Transient Voltage Stability via Quadratic Approximation Method

Based on the quadratic approximation of the stability region boundary, this paper proposes a transient voltage stability margin index, and analyzes the transient voltage stability of a one-generator-one-load system including an induction motor with electro-mechanical transient model. Simulations show that the proposed index has the advantages of high accuracy, high engineering practicability and facility of computer-implementing. And it can be applied to obtain the margin of the transient voltage stability, estimate the critical clearing time in transient voltage emergency and rank the severity of the contingencies. Simulations also show that, for the system in this paper, heavier load and larger portion of constant mechanical torque in the load are more inclined to transient voltage instability.