A method for on-line monitoring of electric tree growth in pressboard of transformers

In this paper, we propose a new method, distributed potential measurement system for monitoring of electric tree growth in pressboard of transformers. Based on the distributed potential measurement system, the position and quantity of PD and the voltage waveform of measuring electrode were obtained on-line. Moreover, According to the voltage waveform of each measuring electrode, the length and depth of electrical tree can be predicted. Multiple experiments were conducted in laboratory, which confirm the space charge position, the prediction of tree's length and the real tree shape in pressboard are accordant. Research shows that the distributed potential measurement system can monitor the growth information and the development of electrical trees online, which lays a foundation for further research on the growth rule of the electrical tree.