The Research Of GIS Partial Discharge Detection Based On UHF Method

With the continuous development of the power grid scale,GIS has broken the traditional concept of the substation,and has so many advantages,such as little occupation area,compact structure,high reliability,short cycle of the on-site installation.However,GIS has stood the test of the safety operation.Once GIS interior appeared some insulation defects or insulation failure,it is extremely easy to cause the equipment to run unsafely and unsteadily.Therefore,it is particularly important to take the test for GIS equipment,in many methods of the detection,the UHF has better application because of the strong anti-interference ability,high sensitivity,convenient detection.According to the present situation of UHF with GIS partial discharge,the paper studies the methods of UHF with GIS partial discharge,from the perspective of the engineering application,for extraction of PD UHF signals,noise inhibition,data acquisition,feature extraction and so on,the following work is mainly needed to completed:The paper overall analyze the type of GIS internal defect,summarized the research situation at home and abroad at present,and compared several common partial discharge detection methods,and then discussed the working principle of UHF,at the same time,the paper discussed the characteristics and development of UHF and some problems that existed in the applications.In order to decrease the noise signal contained in the partial discharge detection for GIS,The paper has done some research of the theoretical analysis,and compared the current wavelet threshold denoising,a new threshold function is posed to eliminate the noise signal.Simulation experimental results indicate that the new threshold function,compared with the traditional soft threshold and hard threshold,is simple to express and easy to calculate,as well,it is more important that the new threshold function can achieve better denoising effect.The paper has researched the composition of the GIS partial discharge detection system,analyzed the UHF sensor and logarithmic detector,and described circuit principle of signal conditioning,and took the key to design the instrument data acquisition card hardware circuit and software proguam of GIS PD,including ADC,the design of acquisition unit and feature extraction circuit,implement FPGA logic circuits,PCI bus interface circuit design and the disgn of the driver,finally,the design of the system has been pilot testing of project implemention,and in the project implemention,the paper mainly analyzed and processed the paramenters of the envelope detection signal,and achieved the desired result.In conclusion,the paper has took more in-depth study in denoising algorithm,signal processing,data acquisition,data processing,feature extraction of partial discharge in GIS,and in the end of the paper,we put forward further problems to research.