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Astrategy Using Apf With Svc To Improve Micro Gird's Electric Power Quality

Posted on:2011-10-19Degree:MasterType:Thesis
Country:ChinaCandidate:W Y ChenFull Text:PDF
GTID:2192330338983587Subject:Power system and its automation
Abstract/Summary:PDF Full Text Request
Distributed generation represents the development direction of the electric energy in the 21st century. Distributed generation can increase the supply ability of the power system; reduce pollution to the environment; improve the reliability and efficiency of the power system. Studies of the distributed power generation technology and improving DG's electric power quality have important practical significance.Micro electric gird is a system including the distributed generation and the load as a unity. It's a controllable system which can be operated both in the interconnected mode and islanding mode. The introduction of the Micro gird supplement the modes of operation of the power grid, but at the same time, it brings a lot of problems, for example, DGs usually access to the grid through inverters and transforms, the inset of the inverters bring plenty of harmonics to the distributing grid; The DG itself can also cause problems such as voltage fluctuation and low power factor. If there exists Micro source or load which has big reactive power demands in the Micro grid, the on-spot compensation of the reactive power is needed to keep the voltage's stability. According to the demands of the distributed generations themselves and the loads, measures must be taken to improve the electric quality of the Micro grid.APF is a devices widely used in the distributing gird for harmonic filtering and reactive power compensation. It usually adopts the Instantaneous Reactive Power Theory for harmonic detection.APF can realize the dynamic tracking and compensation of the harmonic and reactive current; it has fine filtering effect due to its quick response. The controlling of APF is relatively complex. Which more, the investment of APF is often expensive while comparing with its capacity. So it's not a suitable choice from the economic consideration if we use APF as the only compensation device in the power grid which has big demands for reactive power compensation.SVC is a common device for reactive power compensation in the distributing grid which has superior in low price and big capacity. It can adjust the reactive power quickly and smoothly, satisfy the need of dynamic reactive power compensation. In this paper, an APF-SVC combination system is introduced in the Micro gird, APF is installed at the export of the DG to fulfill the function of harmonic filtering and compensation of small volume of reactive current. SVC is installed at the side of the load for on-spot reactive power compensation. APF's quick response can offset the weakness that SVC has slow response to rapid-changing power needs while SVC can make up for the defect that APF has small compensation capacity. Matlab– Simulink is used to build the modes of the electrical devices and power system. Both the control methods in networking mode and island mode are simulated and realize their effective control. On the basis, APF-SVC combination system is introduced to improve the electric quality. Simulation results prove APF-SVC combination system can improve power quality commendably.
Keywords/Search Tags:Distributed Generation, Micro gird's control, APF, SVC reactive power compensation, Combination system
PDF Full Text Request
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