Research On RAMS Evaluation For Power Supply System Of High-Speed Railways

As the quick, comfortable, super large traffic volume and environmental protection transportation mode, high-speed railway has been the important trend of world railway development, which is also an important method to solve the contradiction between supply and demand of passenger transport. During'11th five-year plan', Chinese high-speed railways had been developed greatly. In high-speed railway construction, we made the important outstanding achievements.8358 km high-speed railway has already been put into operation, which provides strong railway transport security for economic and social development. Traction power supply system (TPSS) is the critical components of high-speed railway as the high-speed train's driving force, lOkV dedicated power supply system supplies power to signals and communications. Both of them must meet high reliability, high availability, low maintenance cost and low risk requirements. At present, research on RAMS (Reliability, Availability, Maintainability and Safety) evaluation theory, which is for power supply systems of high-speed railways here, is just initiated overseas and still blank in China.This dissertation is supported by National Natural Science Foundation of CHINA (60674005):RAMS Evaluation Theory and Its Application for Traction Power Supply System of a High-Speed Railway. According to the high-speed railway power supply levels, it has been researched systematically on the evaluation theories of reliability (availability), maintainability and safety for its power supply system. Some innovation achievements have been obtained. The main research contents and conclusions are summed up as follows.In reliability evaluation research, it is researched on the reliability of a bulk power system to a TPSS, the main electrical connection of traction power substation (TPS), 10kV dedicated power supply system, catenary system and its components.(1) Combined with the characteristics of TPSS, the reliability analytical model of a bulk power system to a high-speed railway is established. Four reliability indicators for TPS and five indicators for the entire railway are proposed; their analytical expressions and the sensitivities are deduced. Two quick algorithms, heuristic load shedding strategy and sensitivity matrix load shedding strategy with DC load flow, are suggested. IEEE-RTS 79 example results prove that the analytical model can accurately locate power supply weak links. The reliability of the entire railway will be improved greatly through improving high sensitivity components'reliability parameters.(2) Minimum cut sets algorithm and its programme based on adjacency matrix method are developed to find each cut set order that may result in TPS power supply faults. Seven reliability indicators are established to evaluate reliability value of TPS main electrical connection. Its effectiveness is validated obviously by 220kV TPS example of Jing-Jin high-speed railway.Minimum cut sets algorithm is also used for finding each cut set order that may result in 10kV dedicated power supply system load faults. Power supply reliability of single and double transmission lines are compared by calculating 4 indicators. The same method is also used to choose the laying mode of transmission line. Above results and conclusions are illustrated by analyzing reliability of Yizhuang-Yongle 10kV dedicated power system of Jing-Jin high-speed railway.(3) Both catenary components and its critical components' defects (failures) with treatment measures in high-speed railway are summarized and classified. For fitting catenary components' reliability distribution parameters, an improved least square method and K-S,χ2 test methods for Goodness-of-Fit are introduced. Above methods are applied to count failure data of Jing-Jin high-speed railway, analyze and evaluate reliability of Jing-Jin catenary components and system. Its research conclusions also provide theoretical basis for establishing dynamic catenary reliability model on maintenance actions.In maintainability research, it is proposed that dynamic catenary reliability model and maintenance cost model including components and entire system on cycle preventive maintenance activities. In this dissertation, optimization problem of catenary preventive maintenance plan is transformed into a multi-objective optimization problem. An advanced Choas Self-adaptive Evolutionary Algorithm (CSEA) is proposed for keeping the diversity of population, avoiding individual precocity and enhancing the global convergence compared with NSGA-Ⅱ. It is proved that CSEA is effective and preferable by catenary maintenance optimization example for Jing-Jin high-speed railway. CSEA is also widely used in other muti-objective optimization problems.In safety evaluation research, risk theories are used to evaluate power supply risk synthetically caused by a bulk power system to a TPSS, catenary lines and entire TPSS on moving adverse weather.(1) By means of adverse weather modeling, transmission line's dynamic failure rate is obtained. Probability indicators of reliability evaluation are transformed into risk indicators considering real-time weather condition for bulk power system risk evaluation.(2) Two severity functions, windage yaw risk and ice accretion risk, are proposed for defining the power supply risk events on adverse weathers like strong wind and freezing rain/snow. Each catenary section's real-time power supply risk is obtained by estimating maximum windage yaw and combined load value.(3) TPSS's target hierarchy, criterion hierarchy and scheme hierarchy are proposed for risk evaluation. Analytic Hierarchy Process (AHP) and Fuzzy AHP are used to calculate weight matrix and consistency test result of each criterion hierarchy. Gray maximum correlation method is used to calculate the risk value of target hierarchy.(4) RBTS example proves that, real-time risk indicators and algorithm can calculate real-time risk value of each part and entire system of TPSS accurately in this dissertation, which is for determining the quantitative risk level of TPSS for safe operation. With digital weather forecast, above risk models and algorithms can realize real-time and quantitative risk evaluation for early warning; they also provide theoretical basis for railway dispatching departments'decision-making on adverse weather.