Power System Probability Insecurity Index In Complex Power Injection Space

The probabilistic method for power system securityassessment, which considersthe influence of some random factors on power system security, is an importantsupplement to conventional methods. In complex power injection space, an insecurityindex model reflecting the probability security of power system after a transmissionlinefault is proposedinthearticle. In additiontoconsideringtheuncertainties ofloadforecasting at each node,the fault occurrence location, the fault resistance and thereactive power injection, the uncertainty of the proportion of induction-motor is alsotakenintoaccount.Based on the displacement characteristics of the dynamic security region incomplex power injection space, through reasonable assumption, the article presents asimplifiedcalculationmethodoftheindex.Through much simulation of transmission system dynamic security regions incomplexpowerinjectionspace,experiencedphenomenonarefoundasfollows:1)toacertain fault position, the corresponding hyperplanes of Dynamic Security Region(DSR) of different fault resistances have an approximately parallel property.2) to thesame transmission line, when the fault resistance is given, the correspondinghyperplanes of DSR of different fault positions have an approximately parallelproperty.Based on the phenomenon, a quick calculation method of the correspondinghyperplanes of DSR of different random fault is presented,which improve the speedof the calculation of probability security index. The illustrated examples indicate thattheindexisreasonable.Power system static voltage stabilityregion introduces the concept of region intothe voltage stability research, which make the voltage stability research more direct.The article introduces voltage static stability region into the voltage probabilitystability research, calculate the static voltage instability probability. Static voltageinstability probability takes the uncertainty of load forecasting at each node intoaccount,presents the abundant instructiveinformationforsecurityoperationofpowersystems.