Probabilistic Insecurity Index Considering The Effect Of Fault Cleaning Time

Probabilistic security analysis considers more about the effects of some random factors on power system security than deterministic security analysis. Bring the method of Dynamic Security Region into probabilistic security analysis, we get a model of probabilistic insecurity index, which considers the randomicity of uncertain factors such as fault type, fault position, fault resistance and fault cleaning time. Research in these years has made a few achievements, the characteristic of Dynamic Security Region under different fault position and fault resistance has been identified, but it doesn't include the uncertainty of fault cleaning time, so the probabilistic insecurity index model is not perfect.By investigating the distribution of fault cleaning time and its effect on Dynamic Security Region, we can deduce the following property: 1) the boundary hyperplanes of Dynamic Security Region under different fault cleaning time are approximately parallel; 2) the distances between the hyperplanes under different fault cleaning time are nearly linable.By introducing the concept of extended Dynamic Security Region, which considers the distribution of fault cleaning time, this article gives a simplified arithmetic about probabilistic insecurity index. This arithmetic calculates only two critical power injections under different fault cleaning time and one corresponding Dynamic Security Region. Tests on the New England 4-generator 11-bus test system show that the result of simplified arithmetic is more precise than before, and computation is not notably increased.Based on the above method, we do more research about probabilistic insecurity index under different fault position and fault cleaning time, and we elicit an equivalent fault cleaning time correspond to different fault position. It proves that fault cleaning time under different fault position can be equal to one, and the result is practical.