Study On Nonlinear Discriminant Feature Extraction And Pattern Recognition For Partial Discharge In GIS

Compared with open substation, Gas Insulated Substation (GIS) has the advantages of covering the smaller area , running more safely and reliably, less constant-maintenance, overhauling in a longer period and so on. GIS has been widely used in the construction and reconstruction of urban electric networks.Operation experiences show that intrinsic defects in GIS still cause accidents though its high reliability. Insulation breakdown is primary reason for GIS failures. Partial discharge(PD) phenomena is most common characteristic before insulation breakdown in GIS. By PD on-line monitoring systems, GIS internal defects can be discovered in time to avoid the occurrence of fatal failure. So the research of PD detection and its pattern recognition for GIS is very important to guarantee its safe operation, find out its insulation condition and defects type in time and guide its maintenance.In this paper, the external sensing methods for PD-site testing in GIS are deeply studied based on analyzing researches about PD detection in GIS and its pattern recognition home and abroad, also Fisher Discriminant Analysis and the extending algorithm in PD pattern recognition are introduced, which can rich the theory of the relevant feature extraction in PD pattern recognition. the main achievements are as follows,(1) The Microstrip Patch Antenna sensor applicable for PD-site testing in GIS is developed successfully through the deep research on the external sensing techniques for PD signal in GIS ,during the process, the measures of Opt antenna substrate material, thickness and shape and additional impedance match network are used to expand bandwidth, from which the scope of the broadband antenna is reached, that's to say working band of the Microstrip Patch Antenna sensor reaches 340～440MHz, its center frequency is 390 MHz, relative bandwidth is 25.6% and testing gain of MPA is 5.38dB. In structure, metal materials shielded packaging on the back and part side of the MPA antenna is designed to enhance the ability of anti-jamming.(2) Physical model of four single defects and three hybrid defects in simulation of internal defects are developed, according to PD signal feature in GIS. In the laboratory Microstrip Patch Antenna sensor and high-speed PD acquisition system is adopted to access a large numbers of PD patterns from various insulation defects and construct the...