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A Nomograph Algorithm Of Fault Section Diagnosis And Loads Equalization For Distribution Networks

Posted on:2003-03-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:J D LinFull Text:PDF
GTID:1102360092465719Subject:Control theory and control engineering
Abstract/Summary:PDF Full Text Request
As a result of the development of power systems, the distribution automation system has great application background and tremendous marketable value. The fault section location and the reconfiguration are key functions of the distribution automation system, so they are become of the research direction for a lot of people in the world.However, the efficiency and accuracy of algorithms of fault section location and reconfiguration are related to the topology model for distribution networks. On the base of analysis of traditional models and features for distribution networks, this paper presents a new model ----hierarchical topology model by regarding the distribution network as a graphic. Using the model and states of vertexes, this paper present a new algorithm for loads of vertexes. Because the hierarchical topology model can be employed to identify the zone and branches efficiently, it offers a cogent topological analysis method for distribution networks. The test results showed the effectiveness of the proposed method.Owning to the mutual couplings of distribution networks, it is hard to realize the function of fault section diagnosis. An algorithm of fault section location based on topology identification for distribution networks is presented, by decomposing the topologic matrix which describing the distribution network into two parts which one part only contains the complex coupling factor and the other ignores the complex coupling factor. Using this method, the fault zones in distribution network can be identified and isolated efficiently, and the vertexes of the zones can also be identified automatically. Along with enlargement of scope of distribution networks, the algorithm of fault section location for distribution networks becomes an optimization problem in real-time operation environment. An optimization algorithm based on hierarchical topologic model is presented, where the mutual couplings of distribution networks are under considerations. By calculating fault state of middle vertexes in the region, the region that contains the fault section is compressed step-by-step utilizing subsection principle. Finally the fault section in distribution network can be identified and isolated fleetly. Results of test showed that the method presented is applicable and efficient.Reconfiguration of distribution networks, which is a key function of distributionautomation system, is an important guarantee to enhance reliability of power supply and flexibility of power operating condition. Objects of reconfiguration for Distribution networks are multifarious. This paper chooses loads equalization as object of reconfiguration. Owning to the mutual couplings and branches of distribution networks, it is hard to achieve the global optimization for load balancing, A new algorithm based on hierarchical model and theory of optimization is presented, which can transfer the optimization issues into multi-stage decision-making problems, and can also achieve the optimal loads equalization of distribution networks. Along with enlargement of scale of distribution networks and increment of numbers of regions and complex coupling nodes, the algorithms become difficult to satisfy real-time requirement of practical applications, especially for the restoration of distribution networks. In fact, reconfiguration of distribution networks is just as partition distribution networks into some sub-networks by switches whose position is open. Therefore reconfiguration of distribution networks can be comprehended as partitioning of distribution networks. On the basis of above comprehension, this paper provides a new algorithm----a graph partitioning method that takes loads equalization as optimal object. The method has three characteristics as fellows.First, the loads of regions and branches have to be supplied only by one source of power because distribution networks often exist regions and branches that are belonged to regions. Owing to this reason, we treat feeders of distribution networks as arcs of graph, s...
Keywords/Search Tags:distribution automation system, fault section diagnosis, loads equalization, hierarchical topologic model, Optimal algorithm
PDF Full Text Request
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