Risk Assessment For High Speed Railway Traction Power Supply System Considering Train Timetable

The safety and reliability of traction power supply sytem,the only power sourse for electrified railways,are of great significance to the reliable operation of the entire high-speed railway.Once fault occurs to the traction power supply sytem,the high-speed train loses power,the railway transporation plans will be affected,and great damage may be caused.Thus,it is essential to analyze the possible risk factors in the system and carry out quantative assessment.Therefore,based on the train timetable,this paper carry out risk assessment for the traction power supply sytem under the influence of the train timetable.In this paper,firstly the risk assesement for the traction power supply sytem is carried out from the perspective of the key equipment.For traction transformer,the load characteristics are analyzed after load flow calculation considering the train timetable.Then the winding temperature is obtained though heat circuit model.Considing the risk of life loss and insulation failure,a short-time risk assessement method for traction transformer based on load characteristics is presented.The risk assessment results are presented by means of economic loss.For the power quality risk,risk factors which may influence the safe operation of the system are analyzed,and three risk indices are defined including harmonic risk,negative sequence risk,and voltage violation risk.The power quality data are acquired through load flow calculation with considering the train timetable,and the probability distribution of each risk index are calculated by fitting the power quality data at different time intervals.According to the requirements of power quality in power system and traction power supply system,the severity function of each risk index is defined to measure the risk consequence of the risk.Therefore each risk can be calculated by combing the probability distribution and severity function of each risk index.After obtaining the risk of each electrical equipment and the power quality,this paper applies a comprehensive risk assessment method combing analytic hierarchy process with entropy weight method to calculated the weight of each risk index,and then the comprehensive risk of the traction power supply system is acquired.Based on train timetable,considering both the key equipment and the power quality problems in traction power supply system,the comprehensive risk assessment is achieved.The proposed method enables field personnel to have prompt access to the system risk condition,and can provide strong foundation for railway opereation and maintenance decision-making.