Research On Wide-band Online Monitioring Technology With Multi-terminals For Partial Discharge Of Transformers

On-line detection for partial discharge in transformers is the core of this paper.To solve the problem,A kind of current sensor is developed which using magnetic powder materials.It has flexible space adaptability to the size of transformer bushings,and relevant experiments were carried out according to the characteristics of frequency measurement,experimental results show that the performance can satisfy the requirements of the wide-band measurement,and the influence of the the core material on its measurement performance was carried out by theoretical analysis and experimental test.At the same time,experiments were carried out by wide-band method with multi-terminals measurement of partial discharge in large single-phase transformer platform at 220 k V.The partial discharge signal out of the transformer invaded in it through the transformer bushing was analyzed.A new type of partial discharge in transformer can move vertically near space of windings was developed,which changes through different depths to simulate the partial discharge which has no direct electrical connection with transformer winding.And collects PD signal by wide-band method with multi-terminals from different current sensors.And the final experimental data is processed by using the existing methods,the characteristics and the law of this type of discharge in the multi-terminals measurement of the summarizes,so as to provide guidance for further improvement and development of partial discharge online monitoring technology reference and technology,to construct and perfect the system,and to lay the foundation for the next step of complete testing.