Study On The Relationship Between The Structure And Performance Of A Magnetic-valve Controllable Reactor

Magnetic-valve controllable reactor(MCR), which plays an important role in reactive power balance and voltage stability for the grid, is a controllable static var compensation equipment with a smooth continuous capacity. The researches indicate that a MCR with different structures of magnetic-valves or windings has a different performance(harmonic characteristic or response characteristic). Therefor, this thesis is focused on improving the performance defects of MCR which are larger harmonic content of working current and long response time of transition. Considering the magnetic-valves and windings respectively, the structures of magnetic-valves and windings which have made for a better overall performance for MCR is determined by mathematical modeling, MATLAB simulating and prototype experiments in this dissertation. All the works made in this thesis are to provide a theoretical guidance for enhancing the performance of MCR further. The main contents of this study include the method of modeling and simulating for a MCR based on MATLAB/Simulink, the universal mathematical modeling process of the equivalent magnetization model for MCR's iron core, the modeling analysis and performance comparison for the n-stage saturable magnetic-valve controllable reactor(nSMCR), the current calculation and harmonic current analysis of the continuously saturable magnetic-valve controllable reactor(CSMCR) with a linear magnetic-valve structure, the mechanism analysis of the effects of the winding structures on the response speed for MCRs, the improvements for the quickness of the self-excited MCR, the design and manufacture of a MCR prototype and relevant experimental researches on the harmonic current and quickness. The details are as follows:(1) Based on the equivalent circuit and mathematical model of a MCR, two normal methods for modeling and simulating of a MCR in MATLAB/Simulink are given, which lay a foundation for the later simulation analysis. Especially, the key to make a correct simulation for a MCR is the setting of parameters in the simulation model.(2) The universal mathematical modeling processes of the equivalent magnetization model are presented which apply to arbitrary magnetic-valves of a MCR. Using the universal mathematical modeling processes, the mathematical models of the equivalent magnetization and current characteristic for nSMCR are built. Then the relationships among the main parameters of nSMCR are researched, and the impacts of the magnetic-valve structures on the rated capacity of a MCR are confirmed from the mathematical point of view.(3) The conception of a CSMCR is proposed. As an example, the effects of the linear magnetic-valve on the current characteristic of a CSMCR with this magnetic-valve structure are researched through combining the results of theoretical computations and MATLAB simulations.(4) The harmonic currents, rated capacity and structure complexity of nSMCR are comprehensively analyzed for four design schemes, i.e. quasi optimization, area gradient, radius gradient and optimization, and the relatively optimal design scheme of its stage number and size is determined. Through comparing the overall performance between the linear magnetic-valve CSMCR and nSMCR, the linear magnetic-valve is proved that it has little value in study and application.(5) As winding structure, the MCRs are classified into different kinds and the mechanism analysis of the effects of the winding structures on the response speed for these MCRs are obtained. The simulation needs of the transition processes for MCRs with different winding structures are met based on the multi-winding transformer models in MATLAB/Simulink. The theoretical researches show that the crossing winding structure is so effective to enhance the response speed of an external-excited MCR that the MCR of crossing winding structure has quick response speed than other two MCRs.(6) Two quickness improvements of the self-excited MCR are proposed, and the apparent results are shown by theoretical modeling and MATLAB simulating. Moreover, based on the constructive idea of the two improvements, a conception model about a novel self-excited MCR of quick response type is also proposed.(7) A dry-type single-phase MCR prototype, whose winding could be connected into various winding structures, is designed and manufactured. With this prototype, the character experiment about its harmonics is completed and analyzed, and the theoretical analysis and simulations about the quickness of MCRs are also confirmed by doing quickness experiments.