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Studies On Analysis And Optimization Of Modern Power Distribution Network

Posted on:2016-09-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y H GaoFull Text:PDF
GTID:2272330470963378Subject:Power system and its automation
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The characteristics of modern distribution network are automated, green and sustainable. Our ultimate goal is to build a smart distribution network. In this thesis, some problems on modern distribution network analysis and optimization were studied. The methods for analyzing distribution network, which includes deterministic power flow calculatin and probability power flow calculation, were improved. Combined with the characteristics of modern distribution network, some optimization problems consist of network reconfiguration, reactive power optimization containing intermittent distributed generations, siting and sizing of distributed photovoltaic power station were researched, and chemical reaction optimization was used to solve these complex optimization problems.In order to improve the efficiency of Newton-Raphson power flow calculation, some studies about how to make full use of existing high performance linear algebra package of Newton-Raphson method were done, and the vectorization formula of node admittance matrix and Jacobian matrix were given. To simplify network stratification and iterative process of forward/backward sweep power flow calculation, a sweep iterative method from bottom to up and from up to bottom, which based on breadth first adjacency list, was studied. According to the characteristics of distribution network including intermittent distributed generation, an analytical method based on total probability formula for probability power flow calculation was proposed. The proposed method has advantage of high precise and easy parallel computation. Compared to the method based on cumulant and Gram-Charlier series, the fitted probability distribution curve has no convergence problem and does not violate probability axioms. These works also laid the foundation for modern distribution network optimization.To deal with the constraint of operation times of all switches in dynamic reconfiguration of distribution network, the optimal fuzzy C-means clustering technology was applied to classify the operation state in a time interval according to the intrinsic similarity of load data in a power distribution network; the dynamic reconfiguration of distribution network was converted to the multiple static reconfigurations, in which the load of distribution network is represented using the corresponding cluster center. At the same time, a loop search method, which includes a greedy strategy and improves the performance of loop coding, was given.Aiming at the reactive power optimization problem of distribution nwtwork containing intermittent distributed generations, a probability optimization model, which considers the random fluctuations of both distributed generations and load, and can give an optimal result with probability statistical significance, was proposed.From the aspect of ensuring distribution network including distributed photovoltaic power station showing the nature of load, the siting and sizing of distributed photovoltaic power station in a distribution network was researched. A siting and sizing model for distributed photovoltaic power station, which takes the minimum electricity energy demand from main grid as the objective function, and no reverse power flow in distribution line equipped with circuit breaker and no bus voltage exceeding limit as the constraint, was established.Chemical reaction optimization(CRO) was introduced to solve the optimization models. Some excellent algorithm mode from other intelligent algorithm was incorporated into CRO, and four kinds of collision were appropriately constructed according to the feature of the solved problem, so the CRO has good performance in all solved optimization problems.Multiple sample systems were used to verify the validity of the proposed optimization model and algorithm. The proposed method can obtain best solution in all studied optimization problems with little computational cost and high probability, which indicates good practical value of the proposed method.
Keywords/Search Tags:modern distribution network, distribution automation, intermittent distributed generations, probability power flow, chemical reaction optimization, network reconfiguration, reactive power optimization, siting and sizing
PDF Full Text Request
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