Distribution Network Reliability And Comprehensive Assessment Of The Economy

Distribution system is the directly connected part of the whole power system to customers. Study of the reliability of distribution system, which is concerned by power utility and customers, at the same time is an important research direction of power system. The essential objective of the research on distribution system reliability is to provide safety, reliable electric power to customers and gain the maximum benefit for society.The algorithm of reliability evaluation is an important subject in the power distribution system reliability research. A new method based on successful probability to the evaluation of the distribution system reliability is developed in this dissertation. An example is introduced to show how to evaluate the complex distribution system reliability, which is based on analyzing the working mechanism of the distribution system. The example also compared the new developed method with other traditional methods showing that the new method has advantage in programming, calculating speed and accuracy.The reliability cost and the reliability benefit is opposite in distribution systems. The objective function of the optimization investment strategy of the distribution systems is presented by combining the reliability cost with the reliability benefit in this paper. The consequences of outage to the systems with different deployment schemes of the disconnect switches are analyzed and compared. A theorem is proposed on how to deploy the disconnect switches on the beginning of the main feeder to achieve the best overall benefit. Whether the fuse should be mounted and whether the standby transformer should be prepared in the load branch is particularly discussed and two criterions about this issue are also proposed. The investment strategy of the distribution system network is carried. The lowest cost scheme is found by combining the losses with the investment, which considers the investment strategy both of the utility and of the customer. The scheme is also validated by a test system, results show that the scheme is right and practical.At the end of the paper, the condition and problems of Dongying network are discussed and a real distribution line is calculated based on reliability and economy. Factors influencing the distribution system reliability are also analyzed and some useful measures are proposed to develop the reliability of distribution systems.