Study Of Reliability And Optimal Test Interval Of Subway Protective Relays

With the increasing demand for urban rail transit, the requirements of subway reliability and security are getting higher and higher. So far, according to the domestic and international numerous examples, which prove that the subway protection system is the assurance of safe operation for traction power supply system. In the past, people always put the focus of reliability analysis on first system, which leads to weak theoretical studies of the secondary system reliability. This research is from the perspective of reliability modeling to identify the various factors affecting the protection reliability, introducing of the reliability of assessment methods, establishing the reliability of relay protection devices and their system models, and solving the limitation problem in the past we only concerned about the reliability of protecting the device itself. We will focus on other devices in the secondary circuit, the protection action logic and the effect of protection configuration scheme for the protection reliability.Using GO methodology to the MTR pressure ring protection reliability analysis, it analyze the advantages of the GO methodology in terms of system modeling and the quantitative algorithms, it established the reliability model based on the double-end principle of protection of GO methodology, the model takes into account the impact of the current transformer, fiber channel and circuit breakers and other related equipment protection system, according to the model can calculate the average failure rate and the average time of repair, and other related reliability characteristics.With the equipment operating status of the Metro DC protection system, and considering the protection trip and malfunction state, the establishment of a Markov model, taking into account the different protection configuration scheme to calculate the reliability index of the protection system, and comparing the electrical protection system reliability under the different protection following configuration schemes.Using the Markov model to analyze the reliability of the protection equipment. Improve the transfer of protective equipment in a variety of state law, so that to protect the equipment may be in a variety of state and state transition variable more explicit, and reasonable. Drawn equipment non-use rate with the average repair cycle curve, get the non-use rate of the minimum and corresponding to the average repair cycle, to determine the optimum maintenance cycle.