Operational Risk Assessment Of Overhead Transmission Lines Considering Typhoon Influence

In recent years,with global warming,the sea level has gradually increased,and the frequency and intensity of typhoons have gradually increased,which has seriously affected the safe and stable operation of the power system.Typhoon disasters have a wide range of impacts and strong suddenness,and the results of their accidents on the power system are more serious,especially overhead transmission lines,which are most vulnerable to the impact of typhoon disasters.Once the transmission line fails,it will seriously affect the regional power supply,at the same time cause power grid oscillation and disconnection,resulting in large-scale blackouts.This not only seriously threatens the safe operation of the power grid,but also has a serious impact on the national economy,aggravating the tense situation of power supply.Although typhoon disasters do not last long,their impact is extremely bad,which will increase the outage rate dramatically.If the influence of typhoon disasters on the outage rate of overhead lines is not taken into account,the assessment results will deviate from reality and mislead power system planners and dispatchers.Therefore,it is necessary to establish a fault outage model of overhead lines under climate disasters,to get the failure outage rate,which is conducive to the line risk assessment under climate disasters,and then effectively improve the ability of the power grid to withstand typhoon disasters.Based on the above problems,the transmission line faults caused by typhoon are deeply studied in this paper.Firstly,considering the influence of topography on the spatial distribution of typhoon wind field,a wind field distribution prediction model based on maximum wind speed and radius of wind circle is established.At the same time,the influence of micro-topography on wind speed is quantitatively revised to realize wind speed calculation at different spatial positions.Based on the historical typhoon data,the correlation of wind speed and direction is analyzed,and a continuous joint probability density model of wind speed and direction is established.Combining with the static force balance characteristics of each power equipment,the maximum withstandable wind speed of conductor,tower and suspension insulator string is analyzed.Based on the joint distribution probability density of historical wind speed and wind direction,the fault probability prediction model of transmission line windage deviation and broken tower inversion is established.At the same time,according to the factors affecting foreign body hanging line,the foreign body hanging line fault based on the fuzzy tomography analysis method is deduced.Probability prediction model.Then,the impact of different types of faults on line failure rate is integrated to realize transmission line risk early warning online.Finally,this paper uses the MATLAB program to realize the prediction model algorithm,and uses the line operation case to verify the validity and accuracy of the model.In summary,based on transmission line parameters and historical typhoon data,this paper will establish typhoon prediction model and transmission line fault prediction model to obtain accurate original reliability parameters,and also lay the foundation for reliability evaluation of the whole power system.