Primary Exploration On The OCS System Reliability And Study On Contact Line Reliability

The Overhead Contact Systems (OCS) is one major component of railway electrification. Because of its long length and large number of sites, the OCS is changing dynamically all the time by interaction with pantograph and affection of the wind, frost, snow and ice. Since there is no emergency power supply, power-cut by fault will halt the train. Power-cut has a wide effect and it already became one of the restriction factors for railway electrification presently. To reduce the fault time, the number of power-cut and bring up the railway electrification to a new level, it is imperative to improve the OCS reliability.In this paper, we introduced the current situation on the reliability of both domestic and international study. We then analyzed the importance of study on the OCS reliability and suggested that the innate OCS reliability is determined at the designing stage. As a result, the study on OCS reliability should be started from designing stage as well. So, it is first important to guide and testify the OCS design by performing reliability study. We also compared the traditional design method with the reliability design method.As the property of OCS, we define the OCS reliability as a certain time in which the OCS components (or whole system) can work smoothly. We proposed several factors to evaluate the reliability of OCS, which include reliability and unreliability, failure ratio, life expectation, repair frequency and mean time to repair (MTTR). We further discussed the reliability models of part strength-the interference model of strength distribution. We demonstrated that every design has a possibility of interruption or failure. What the designed can do is to make the possibility of interruption or failure under a certain level or acceptable.We discussed the Neural Network used in study the OCS reliability. By comparing the BP neural network and vertical dimension neural network, we choose the one type of neural network suitable for this project.In study the OCS reliability, we define OCS as the comprehensive system which comprises of contact suspension, Structure and Assembly, Rgistration Assembly, mast and base, Termination Equipment. After comparing the common methods used in analyzing reliability, we suggested that the fault tree model should be used, we set up the fault tree model of OCS. Based on Markov model of reliability analysis, we gave some practical methods to improve the reliability and usability of the OCS;In analyzing the contacting-line reliability, we practiced and calculated the contacting-line fatigue strength by certain vertical dimension neural network. We calculated the contacting-line strength by related rules with limited time model, and further analyzed contacting-line reliability. By computing fatigue reliability, we found that increasing train running speed can reduce the fatigue reliability of contacting-line. The fatigue reliability can also be decreased by lowering the raising force of pantograph and increasing the working tense of contacting-line at certain degree.