Electrical trees were generated experimentally in the actual 33 kV underground XLPE cable material under the AC Voltages. The formation of tree like structure and a Bush type of tree structure was observed near the defect site of the insulation structure. The importances of the Weibull parameters for understanding the growth dynamics of electrical trees were explained in detail. To understand the point of inception and propagation of electrical trees, in the present study acoustic emission technique was adopted. It is observed a characteristic change in the frequency content of the acoustic signal as and when the tree propagates in the insulation structure. The partial power measurement used in the study provides an indication to the growth of electrical trees and to the near instance of failure of polymer insulation material due to electrical treeing.