Analysis Of No-load EMF Waveform For The 1000MW Hydro Generator

1000MW hydro-generator is the maximum capacity of the huge hydro-generator at home and abroad. The research on such huge hydro-generator is still at an early stage, and there are all kinds of problems need to research, such as design, operation and theoretical calculation, etc. Abundant water resources in China, hydropower has the broad prospects for development on the present and future.No-load EMF waveform distortion rate is the fundamental of measure power quality, it is also a key for conventional generator. Methods to calculate no-load EMF change from analysis to numeral. Method of field coupling circuits can consider saturation of iron core, end rings of damper windings and end leakage into account. The unit machine time-step finite element mathematical model, which is suitable for hydro-generator, is established firstly in this paper. The method for solving the region between stator and rotor was defined. The 2D geometric model is established according to structure of 1000MW hydro-generator. This paper analyzed what factors is affecting no-load EMF waveform.The structure of damper windings have considerable effect on tooth harmonic components of no-load EMF, tooth harmonic component is high, which give rise to high distortion and bad waveform. The structure of damper windings is divided into three cases, it were damper winding pitch, the number of damper winding slots and shifting the center of damper winding. According to each case to draw a variety of different schemes, this paper calculates no-load EMF waveform, harmonic and air gap flux densities by the method of 2D field coupling circuits.At last, This article analysed the rule of damper windings influence on no-load EMF with different cases. Then the no-load EMF waveform is improved.Finally, based on practical examples of power plant, this paper designed the pole of 1000MW hydro-generator three arc structure. This paper presents a variety of programs which is about optimization of structure of damper windings and three arc pole on the common, and establishes the finite element model. The data table of harmonic content and the trend figure of distortion are given from finite element method and harmonic analysis.In this paper the optimal results and conclusions are both obtained for each situation, and provided research and design of huge hydro-generator with valuable reference. The work of calculating no-load EMF waveform and different optimization is of some practical value.