Research On Partial Discharge On-line Detection Of XLPE Cable

XLPE cable has been widely applied in power system. Its reliability is directly related to security and stability of power system. Partial discharge detection is an effective method to analyze the insulation degradation degree of XLPE cable. There is an urgent need for XLPE cable by partial discharge on-line test in order to achieve the status maintenance. This paper researches on XLPE cable partial discharge detection.For the characteristics of XLPE cable partial discharge signal, design a wideband current sensor with wide frequency band and good frequency characteristics. By analysis and comparison, determine the optimal parameters and verify the performance of wideband current sensor.Based on the previous studies and experience, develop a set of system which can be used for XLPE cable partial discharge online detection. The system's hardware devices include sensors, discharge filter circuit, the acquisition card and industrial machines. The system's software is written with LabVIEW. It implements acquisition, de-noise and spectrum display of partial discharge signal. Software system uses automatic threshold de-noising method based on GHM multi-wavelets to de-noise. The simulation results show that the GHM multi-wavelet automatic threshold method is effective. Use this method and wavelet de-noising method to process simulated data and on-site partial discharge detection data. The results show that it has the ability to retain the original signal information.By the analysis of the types of XLPE cables partial discharge, four discharge models were produced to simulate. And simulate test on the developed partial discharge detection system in this paper. Results verify that it can detect partial discharge signal effectively. In order to better display the characteristics of partial discharge signal, design two-dimensional and three-dimensional spectra and spectra display and analyze the four discharge models data.