The Wind Power Plant In The Low Voltage Ride Through With The Study And Protection Actions

In the modern society, green power becomes more and more important. Windpower as kind of clean and renewable energy, meanwhile it’s unlimited, it gets moreattention of all over the world. The wind power generation in China grew very fast,too. With such rapid development, some problems have been exposure. For example,a large number of wind power have connected to the grid, the grid can easily breakdown when the system fault occurred since the turbines easily cut out from the grid.Therefore, our country stipulates the large wind turbines must have the ability tocomplete the low voltage ride through (LVRT). This paper mainly discusses the LVRTtechnology of the direct-drive type permanent magnet synchronous generator (PMSG)wind power system.Firstly，this paper analyzes the method and principle of LVRT, then the mathmodel of grid side inverter was built through the analysis, after that a simulationmodel of grid side inverter has been built in MATLAB/Simulink. The method whetherput the DC-link crowbar protection circuit operate or not according to the conditionsof power difference and dc voltage is proposed, meanwhile the problem of thecrowbar working quickly and reliably is also solved in this paper.Through the simulation contrast, this paper has a conclusion that the grid sideinverter and DC-link crowbar protection circuit coordinated control can significantlyimprove the PMSG system’s LVRT ability. The proposed LVRT control theory isverified. At last, the importance of LVRT and relay protection actions work togetherand the necessity of LVRT and relay protection actions coordinated operation areintroduced in this paper, and several methods of cooperation are also introduced.