Research On The Fuzzy Reliability Analysis Method Of Distribution Network Communication Passive Optical Network

Distribution automation system(DAS) is an important content in the construction of Strong Smart Grid, distribution network communication system is the key part of DAS, the reliability of distribution network communication system is a necessary condition for the correct operation of DAS. As an optical access technology, EPON with its unique advantages gradually becomes the best choice of the distribution network communication access layer technology. So it is necessary to analyze the reliability of the distribution network communication EPON.Traditional reliability assessment methods need a large amount of accurate statistics. But in engineering practice, the collected data is often not precise or not enough. How to carry on the reliability evaluation in such cases has become a realistic problem. Meanwhile, traditional reliability theory is based on the probability assumption and binary-state assumption, but in many cases, binary-state assumption is not enough to describe the actual situation, such as the descriptions of degraded operation system. Therefore, this paper introduces the fuzzy mathematics theory into reliability research to analyze the fuzzy reliability of distribution network communication EPON.This paper first determines the EPON networking in distribution communication network, establishes the reliability model of EPON based on optical fiber wiring diagram, which makes the research more accord with the engineering practice. Based on the research of the fuzzy reliability theory, we adopt two methods to analyze the fuzzy reliability of distribution network communication EPON. One method is fuzzy probist reliability analysis method. EPON component reliability parameters have a certain uncertainty due to the incomplete or not comprehensive data or estimated bias etc. This method uses fuzzy numbers to represent the component reliability parameters, the fuzzy reliability of the system is obtained by means of fuzzy number algorithm and EPON reliability model. This method solves the problems of reliability analysis under the condition of parameter uncertainty. Another method is the profust reliability analysis method. The EPON system within the region is considered as a whole, EPON system usually contains more than one ONU, this method defines the system fuzzy state and its profust reliability in different numbers of normal communication ONU and analyzes the EPON system profust reliability based on the Monte-Carlo simulation. This method solves the reliability analysis problems under the condition of fuzzy system state. This paper breaks through the traditional reliability analysis methods, studies the fuzzy reliability of EPON, the fuzzy reliability method is more suitable for practical engineering requirements. It is expected that the results can not only provide some reference for the research of fuzzy reliability theory, but also provide some guidance for the construction and modification of distribution communication network.