Research On Reliability Of Power Communication Networks

Power communication network is a private communication network for power system. It has high requirements of real-time, reliability, and security in services. The reliability of power communication network is one of the most important factors influencing security and stability of power system. It takes an important role in performance evaluation and management assessment of the power systems. In power communication network planning, reliability is a key constraint. Compared to public communication network, reliability research of power communication network lags behind relatively. On the basis of the analysis for power communication network reliability requirements, establishing an objective and accurate reliability model, proposing comprehensive evaluation method corresponding to the characteristic of power communication network reliability, are main research topics.The structure and services types of power communication network are analyzed, the requirement of each services are clarified. By comparing the concepts of reliability, availability, survivability and security, the concept of availability is used as reliability measure to research the comprehensive reliability of power communication network.The internal structure of the equipments and the power supply systems are taken into account, and then availability models of dedicated, multiplexing and active-standby optical channels are constructed. These models can reflect the logic relation of internal components in communication equipments states and the influence of power supply system on circuit availability is considered. The analytic results are in conformity with the needs of reality. In view of the dispersion of availability parameters for communication infrastructures, the triangle fuzzy number method based fuzzy availability models of communication circuits and its analysis method are proposed. This method has solved the uncertainty problem of parameters effectively.Aiming at the question of availability analysis of power communication network services, the importance of power communication services is evaluated. The service availability model based on service importance and its analytic algorithm are proposed. The algorithm considers the influence of shared network elements on services availability. The variation trend of network services availability at different services traffic threshold is analyzed. The risk theory based importance assessment of shared network elements is provided. Evaluation results show the distribution of network's vulnerabilities.Combining the characteristic of power communication network management and operation environment of power communication network, the influence factors for reliability are analyzed. Consulting the standard end-to-end communication security system architecture and evaluation mechanism in the industry of electric power communication, security layering is defined and the reliability comprehensive evaluation indicator system is established. To reduce the subjectivity of indicator weight, improve the objectivity and credibility of evaluation results, a comprehensive evaluation method of reliability based on improved Fuzzy-AHP is proposed. The fuzzy weights are calculated on the basis of LLSM. The restricted coefficient method is used to de-fuzzy the evaluation results. The uncertainty of reliability assessment in power communication network is solved; the effectiveness and feasibility are verified by evaluation examples.