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Reliability Evaluation Method For Complex Distribution Networks

Posted on:2016-02-20Degree:MasterType:Thesis
Country:ChinaCandidate:S W YanFull Text:PDF
GTID:2272330461457187Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the excessive consumption of traditional energy, its emissions have caused the extreme pollution to the environment, and a growing number of people have realized the importance of environmental protection, thus people begin looking for a way to reduce the consumption of traditional energy. Because distributed generation is featured by security, economy, environmental protection, renewability, small capacity and flexibility, while the electric cars, as a new generation of vehicles, have incomparable advantages compared with conventional ones, the distributed generation technology and electric vehicle technology are two important means of energy conservation, and the scheme of introducing distributed generation and electric vehicle charging station into distribution network has been put on the agenda. Also, because the distributed generation and output of charging station is essentially random, and with the growing development of the smart grid, an increasing number of protection devices of controllable-switch have been applied to the distribution network, which thus is increasingly complex. These changes will largely affect the service ability of the distribution network, making it more difficult to assess the reliability of power supply. As for conventional reliability methods, because these influencing factors are not taken into consideration, there is a defect in the reliability assessment of distribution network. Therefore, to seek a way that can meet the future development of reliability assessment has been increasingly emphasized by the power sector.Based on the extensive literature, starting with the analysis of traditional distributed generation output, this article has made analysis and study of reliability assessment method of distribution network with distributed generation, and on this basis, has proposed the reliability assessment method of distribution network concerned with capacity constraints of components. At last, taking into account the capacity constraints of elements, the article has proposed the reliability assessment method of distributed generation containing electric-vehicle charging station. Details are as follows:1) It has established the power model of DQ EV and load, deriving the calculation method that load obtains effective power supply probability within DG service area, and further establishing the reliability evaluation model of various load points in distribution network with distributed generation, and on this basis, has constructed indicators that can reflect the impact of DG on the reliability of power supply of load-point, and has proposed reliability assessment method of distribution network concerned with DG power supply probability;2) It has established the model of elements and distributed generation within distribution system in running state, studying the effects of capacity constraints of element on the distribution network, and establishing the reliability model of load points in distribution network with distributed generation and concerned with capacity constraints of components to construct indicators that can reflect the impact of component capacity on the reliability of distribution network load-point. Also, it has further proposed the reliability assessment method of distribution network with distributed generation and concerned with capacity constraints of elements, and on this basis, has proposed the reliability assessment method of distribution network including electric-car charging stations;3) It has proposed a control strategy of fault self-recovery of distribution network, which takes into account the importance of the different load points in the distribution network. It takes supply the maximum equivalent power of power-up or the maximum number of equivalent valid users of power-up in power supply interrupted region as the objective function, controllable power balance in fault isolation region as constraint conditions. When the constraints of component capacity are concerned with, it puts forward corresponding constraints when components in different positions are overloaded, solved by traversal method.Through the analysis of IEEE-RBTS Bus6 system, it has confirmed that the fault self-recovery strategy proposed in this article can well improve the reliability of power supply of the equivalent payload in distribution network, and that is, the higher the load level is, the higher the reliability of power supply in this method will be accordingly. Indicators constructed can reflect the impact degree of distributed generation output and capacity constraints of components on the reliability of load-points within the distribution network. Also, the proposed reliability assessment of the distribution network is correct and practical.Indicators constructed in this article have provided theoretical support for the choice of constant volume and future construction of distribution network of distributed generation within the distribution network. The established control strategy of fault self-recovery of distribution network has provided a theoretical basis for the best action strategy of post-failure protection equipment of smart distribution network. The article has proposed a relatively comprehensive method of reliability evaluation of distribution network, and the research results are of great significance to guide the construction and transformation of distribution network and to improve the management of distribution network.
Keywords/Search Tags:Complex distribution networks, reliability evaluation, distributed generations, electric vehicle, component capacity
PDF Full Text Request
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