The Research On On-line Measurement Of The XLPE Cable's Partial Discharge

XLPE cable is the primary transportation equipment in electric power system and Partial discharge (PD) is the main cause which destroy electric power's cable insulated layer. On-line measurement of the XLPE cable insulated layer's Partial discharge is important method to detect hidden trouble, forecast equipment longevity and ensure electric power cable run on the safe side.This dissertation mainly research on design XLPE cable on-line measurement system and eliminate locale interference noises. The modern digital signal process in information science and micro-computer control in computer science are adopted in the dissertation.Firstly, in order to gain technology foundation on the on-line measurement system, the research status quo, technology background, characteristic and applications of XLPE cable's PD are analyzed.Secondly, logical framework of the cable's PD on-line measurement system, realization's theory of function module and application pattern is proposed. Wide frequency bandwidth electromagnetic coupling transducer, amplifier circuit and data gathering module are mainly designed in the dissertation.Thirdly, based on analyzing variety of interference noise in detection of cable's PD, different anti- interference measurement are adopted aim at different interference. The cascade 2nd order IIR lattice notch filter is adopted to restrain periodical narrow-band interference and the wavelet transform is adopted to restrain white noise. Lots of simulation experiments are done to verify filtering effect of different methods. Performance of filter gain distinct improvement by select appropriate wavelet coefficient.Lastly, structural model is established by reasonably combining several measurement of anti-interference. Simulation experiment and locale data process indicate that structural model proposed in the dissertation is applicable for interference restrain in complex locale condition.