Equivalent Machine Transient Energy Function Method for Transient Stability Assessment

摘要

Two problems shall be solved when hybrid method is applied for on-line Transient Stability Assessment for large-scale power grid: one is how to determine whether system is stable or not from large amounts of trajectory information output by time domain simulation; the other is how to figure out transient energy margin along fault trajectory. Enlightened by experiences formed in long-time running, it is proposed in this paper that we can assess system stability by transient energy reflected by relative moving of machines. Concepts of Equivalent Machine and Equivalent Machine Transient Energy Function Method are proposed based on single machine transient energy function method. Simulation results illustrate the validity of the method. It suggests that we can determine whether system is stable or not and obtain system transient energy margin from relative moving trajectory between critical machine and reference machine.