The Detection Unit And Digital Signal Processing On Partial Discharge For Power Transformers

The insulated state is one of the most important problems of large power transformer safely running in power system. The most efficient method in monitoring the running transformer's insulated state is to extract partial discharge signals in real-time. In this paper, the essentiality of developing online partial discharge monitoring, the actuality and develop trend in home and abroad are discussed. In order to solve the problem in online monitoring system, a high effective detection PD circuit is designed, at the same time, wavelet transform and DSP technology are applied to improve capability in real-time process.Firstly, pulse current method is used to inspect PD signals based on the theoretic analysis to PD characteristic of transformer. In hardware circuit implementation, notice to choose signal sensors, signal magnify circuit and filter circuit are reasonably designed, at the same time, highspeed data sampling circuit and large capability storage circuit are designed, the hardware circuit PCB is made. Then the data sampling circuit is connect with TI DSP develop system to process PD signals further.Secondly, wavelet analysis is suit to extract break signal, so, it is programmed to implement the function of filter and signal extract.Finally, simulated examination is done after the hardware and software design. The simulation results show the designed PD signal detection unit and adopted software process method is effective.