IMPROVED TECHNIQUES FOR HYBRID METHOD IN FAST-TRANSIENT STABILITY ASSESSMENT

Theoretical background and the development of new techniques for the i mplementation of hybrid methods in online fast-transient stability ass essment are presented. For evaluation of transient energy margin (TEM) along a trajectory, a transformed transient energy function (TEF) is defined. It is proved that along a postfault trajectory the transforme d TEF is conserved. Based on the conservation principle and using tech niques such as integration stopping criteria and location of the main potential energy peak, an improved pseudofault method for TEM evaluati on is reported. These techniques have been tested on several test powe r systems with different system models. Results show that the proposed techniques are useful. An example shows the improvement of the techni ques over the recently published hybrid method.