Reliability Study Of The Transmission Line Based On The Theory Of Markov

The reliability of transmission lines is closely related to the reliable operation ofpower grids． With the gradual expansion of the scale of power grid, power networkstructure of transmission line is more and more complex, the importance of reliabilityevaluation of operation state of transmission line has been perceived. However, inactual transmission line has a wide geographical distribution, detection of multipleparameters, complex operation environment characteristics, leading to complex dataanalysis problems as a direct result. Therefore, there is an urgent need to establish asimple and effective means for the reliability assessment of transmission lines.This study propose a mathematical model based on the reliability of thetransmission line theory of Markov, transmission lines under the premise that thefailure rate complies with exponential distribution characteristics, transmission linesrunning reliability analysis based on Markov chain model. The proposed transmissionline state transition diagram, based on the line running historical data or simulationdata of sample transmission line, a Markov state transition probability matrixequivalent to transmission line is attained. On this basis, the use of state transitionprobability matrix and transmission line current operating status, resolve to gettransmission lines running state changes the probability of future time and itsavailability, and reliability assessment of transmission lines.Further, several blackouts and large-area outages around the globe have beencaused by cascading failures in the past several years, and hence forecastingcascading failures has become one of the most important research topics in powersystems. The existing methods of forecasting cascading failures do not systematicallyand comprehensively address some important influencing factors such as the networktopology, and the relevance between two consecutive failures. Given this background,based on the initial failure probabilities of lines and the transition probability betweentwo consecutive failures, a Markov chain based model for forecasting cascadingfailures is presented and the transferring power flow, as well as the failure rates ofcomponents is taken into account. At first, the next failure is forecasted by theMarkov chain based method, and the set of possible failures identified, followed bythe paths of cascading failures with the time sequence determined. Then, three criteria used to evaluate the vulnerability of follow-up failures arc presented, and employed tomonitor and quickly control possible cascading failures. Finally, the RBTS-6bussystem is served for discussing the theory of the line based on Markov chain failedpath.