Abstract: Insulation performance of XLPE power cable is closely related to the formation and development of its water trees. We employ AC voltage superimposition approach to monitor its insulation status. We also establish a Duffing chaotic oscillator with 1 Hz periodic driving force to accurately measure 1 Hz characteristic current by means of its characteristic that it is sensitive to the signal whose frequency is identical with the periodic signal, but suppressive to noise.Simulation results show that its detection precision is 10 nA.

Key words: XLPE power cable, online monitoring, AC superposition, Duffing chaotic oscillator