Research On A Kind Of Multi-Functional Solid-State Current Limiter And Application In Wind Power Grid

With the expansion of the grid scale, wind power has become an important source of electricity. In order to solve some drawbacks of wind power of its own, scholars have made unremitting study internationally. But how to make wind power become large-scale, high-efficiency power generation still require effort, which is also the internal need of the construction of smart grid and strong grid.First, we investigate the status of domestic and international wind power technology and solid state fault current limiter. Relying on the National Fund for the project, we analyze the practical significance and application prospect of the application of the SSFCL in improving the performance of the wind farm, and thus draw a conclusion.Then, we introduce two kinds of voltage regulation devices, namely dynamic voltage regulator (DVR) and series dynamic braking resistor (SDBR), which are applied to the low voltage crossing of the wind farm. and separately analyze the topological structure and working mechanism of the DVR and SDBR. On this basis, we propose a new topology of multifunctional SSFCL (hereinafter referred to as the "new multifunctional SSFCL")for wind farm low voltage crossing.And its working mechanism is analyzed in detail by simplifying the topology structure. Finally, the functional simulation analysis of DVR, SDBR and the new multifunctional SSFCL are carried outrespectively, which verify the correctness of the new topology structure and working mechanism.Finally, the feasibility of the new multifunctional SSFCL connected to grid port of voltage regulation is analyzed theoretically. On this basis, a new hybrid control strategy is proposed for the new multifunctional SSFCL.The simulation of the new multifunctional SSFCL applied to improve the fan low voltage crossing capacity are conducted under five situations that grid voltage drops 5%,20%,50%,80% and 90% respectively. After analysis, we come to the conclusion that the new multifunctional SSFCL can effectively improve the wind farm low voltage crossing capability.In order to verify the correctness of the theory, we design a multifunctional SSFCL laboratory prototype with dynamic voltage compensation, fault current limiting and lifting fixed voltage. After several hardware testing and debugging, we get the waveform diagrams of the experimental prototype of the three functions, which verify the correctness and feasibility of the theory.