Calculation Of No-Load EMF Waveform And Optimization Of Damper Windings For Powerformer

Powerformer, a kind of new power equipment, is introduced in this paper, which can be connected to electric network directly. By breaking century old conventions, the conventional generator, the generator surge arresters, the medium-voltage generator breaker and busbars, and the step-up transformer are all replaced by one single component. Advantages of low cost, high efficiency and low maintenance expense make Powerformer a wide developing prospect. No-load EMF waveform is a key for conventional generator. To assess the power quality of Powerformer, it is needed to study no-load EMF waveform. Methods to calculate no-load EMF change from analysis to numeral. Common method is solving 2D transient field by FEM, but it can not take the current constrains caused by damper end concrete connection and end leakage into account. Method of field coupling circuits can consider above factors and calculate no-load EMF accurately. The design principle, character and prospective development of Powerformer are introduced firstly. Then the mathematical model considering concrete damper end connection or not is proposed and model is established according to structure of Powerformer. No-load waveform with different damper constrains of Powerformer is calculated, and compared with the results disconsidering damper end connection , magnitude of tooth harmonic components have some different. The method of considering damper end effect is certified by experiment. Harmonic analysis shows that tooth harmonic components of no-load EMF waveform is considerable high, which give rise to high distortion and bad waveform. In all measures of improving the no-load EMF waveform, the structure of damper windings have considerable effect on tooth harmonic components of EMF waveform. The EMF of different damper windings is calculated, the effect of damper windings on EMF is analyzed. The no-load EMF waveform is improved by modifying the structure of damper winding. The work of calculating no-load EMF waveform and optimization of damper windings is of some practical value, which can be referred in the engineering computation.