Analysis On Generator Fault Of Variable Speed Constant Frequen Cy Wind Power Generator

Contemporary development of wind energy utilization increases ceaselessly and wind generators installed capacity increases ceaselessly, and the proportion in the whole electric power system is increasing. a serious fault of Large wind power generator in the course of its operation not only result in the motor itself damaged, but also may result in partial or whole power system fault. Large wind power generator is expensive, with the ratio of wind power in the power grid continues to increase, if the generator power supply interruption, the loss will be more and more.Generator wind turbine is as wind energy into electrical energy device, which not only affects the whole wind power conversion system performance and structure complexity, but also affect the output electric energy quality and efficiency. Therefore, there is an important significance in the wind power generator unit fault diagnosis, either in the avoidance of major accidents, or in the wind machine to find out the fault causes, fault repair and guarantee the safe operation of power grid.Direct driven permanent magnet wind power generator (D-PMSG) is for the fault research object in this paper. Firstly, when generator short circuit fault happens, the rotor current is derived according to the basic theory of the PMSG. Secondly, using the finite element method for direct drive permanent magnet synchronous generator with internal electromagnetic field, deduces the magnetic vector potential A and current density J, and discusses the wind generator moving boundary value problems of electromagnetic field, the triangle element meshing and the linear interpolation method and establish the discrete equations of finite element analysis, solving questions of the movement of the limited element method processing with the time step method, which are the foundation using finite element method for the establishment of direct drive permanent magnet wind turbine generator.In the foundation of the limited element method,2.12MW D-PMSG was established with RMxprt which is a field-circuit-motion directly coupled time-stepping finite-element analysis model. And then import the model to two-dimensional electromagnetic field model Maxwell2D, the output voltage, current waveform and2D electromagnetic field waveform was calculated, which prove the RMxprt model was correct and accord with the index of wind turbine. By changing external stator circuits, all the short circuit calculations of stator can be implemented including stator winding phase short circuit, two phase short circuit, short circuit current and voltage of each phase and fault state model of electromagnetic fields in the air-gap flux density and D-PMSG internal magnetic field distribution, and analysis of the different fault comparison of results. At the same time, the paper analysis the stator inter-turn simulation faults, calculate the A phase voltage, magnetic cloud density and air gap flux density when A phase occur2%stator winding inter-turn short circuit.The research results of this study are expected to supply the important basic theories and methods for the on-line monitoring and fault diagnosis of large D-PMSG.