Reliability Evaluation Of Distribution System Based On Monte-Carlo Method

Distribution network is part of the power system that directly connected to the customs. As the development of the society, the requirements of the customs enhances unceasingly; lots of organizations require continuous high quality power from the distribution network. The development of the society also makes the sizes and the complexity of the distribution network increase ceaselessly. For the construction and renovation, the assessment of the distribution network is one of the most important aspects. The improvement of the distribution system reliability not only benefit from the customers, it also has a vital role for the whole power system reliability advances. Using distribution system reliability assessment can evaluate and transform the existing power grid; it can also guide further planning and expansion of the distribution network.Reliability evaluation of the distribution system mainly divides into analytic method and Monte Carlo method. This paper introduces the basic concepts of power distribution system and its characteristics, and gives the common indices of distribution system reliability evaluation. It has expounded reliability evaluation of distribution network based on Monte Carlo simulation. The Monte Carlo method obtains the system state by means of random sampling, through sample statistics to estimate the frequency. Using the idea of Monte Carlo method, a sequential MCS of the load model was established in this paper, which considered the impact of load and system by component failure, component refuse and planned maintenance. Aiming at the multi-feeder complex distribution system, an improved fault traversal MCS method was presented, search the components in unit; creating the status table of the components can localize the blackout load causing by fault quickly and enhance the calculating efficiency. Using the timing characteristic of the sequential Monte Carlo, the paper calculated reliability points of load and system; basing on that, it also calculated the distribution rate of the loads'interruption frequency and duration, which has made a comprehensive in-depth analysis for the reliability of the distribution network in the perspective of the probability.Based on the simulation model, this paper wrote software using C++ Builder 6.0 and Microsoft Office Access 2003 as platforms. The software has visual interface that can establish and revise the parameters of the distribution network conveniently and calculate its'reliability index.The test result by IEEE RBTS shows that the model and the software are rational and effective. By the results of simulation, this paper summarized the measures for improving the reliability of distribution network, which include installation fuse in load branch line, adding circuit breaker, disconnector and backup appropriately. At the same time, adopting the automatic power switch and reducing the switch time of system component fault can reduce both the failure rate and time of the load.