The Fuzzy Theory-based Research Of Distribution Network's Capability Evaluation And Reliability

As the main component of power system, the downtown distribution network is one of the most important basic facilities for a modern city. Its quality has not only impact on the operating security of power system, but also on the development of other fields within the whole economy system. To measure its capacity and reliability accurately is beneficial for assessing the current status of network and planning further improvement. At the same time, it's also meaningful for the power system to get more profit. So far there is no common specification to measure the capacity of power system. Generally there are some factors including(load of line, voltage excursion, line lose and the analyse of N-1 calculation) which are widely used to verify the corresponding restraint during the distribution network's operation. Whether the capacity is better depends on how many lines can meet the restraint. The research on reliability is made up of 2 parts: the statistical analysis on the data of reliability and the forecast for future. The former is to analyze and evaluate historical data of the running distribution system, and the latter is the estimation to build new system or upgrade existing system. They are the two sides of one coin.At present time there is no one integrated model to evaluate the capacity andreliability of the whole power system. A new resolution to evaluate the capacity of downtown distribution system is submitted based on current technology and the task. A new approximate ratiocination and decision-making method based on fuzzy logic is applied to the estimation of downtown distribution system's capacity. A detail model and some guide lines for assessing the quality of downtown distribution system are created and corresponding reliability estimation is also discussed. As for the problem that the reference model cannot give the measurable guidelines, a new method based on fuzzy theory is provided that correct remarks for power system's capacity can be given by making use of appropriate special function. During the dissertation, data structure, flow calculation, reliability guide lines and critical techniques are involved.In last section, the distribution network of some city is analyzed and its capacity gets appropriate estimation. At the same time, the implementation process of this paper's design strategy is described carefully, considering the aid of developing tools. Also the trend of this paper's topic and the next possible improvement is discussed.