Study on pulse current of typical PD models in power transformer

In power transformer, partial discharge (PD) detection is an effective means for monitoring and evaluation of dielectric faults in an early stage of development. Traditional PD detection methods cannot completely depict discharge mechanism of insulation system, so pulse current of PD should be investigated. In this paper, a broad band measuring system is developed and the high speed digital oscilloscope TDS680B is used to measure pulse current of PD. The whole setup is tested by the PD pulse of standard corona model. Then several typical PD defect models in power transformer are designed and these pulse current are measured by this system. Results show that, the PD pulse in oil is always instability and oscillatory. Moreover, for different models, the parameters of pulse are different, which can be made the reference of PD pattern recognition