The Assessment Of The Severity Of Partial Discharges In GIS Based On The Features Of Spectra

Gas insulated substation (GIS) has been widely applied in the field of high voltage power transmission. However, GIS equipments are witnessing more and more internal faults and failures as the voltage class of power network and capacity of power system keep upgrading. A great need is therefore in existence to search for an effective way in assessing the internal insulatin conditions of GIS equipments. Serving as the most important measure means in this regard, the severity of partial discharge is mainly judged by visual method of comparing spectra and combining with experience. Neverthless, this method is subjectivy, lack of scientific and accuracy, and low efficiency. Therefore, a mothod to assess the severity of partial discharge in GIS based on the features of spectra is put forward by analyzing tne relationship between features of spectra and severity of partial discharge with digital image processing techniques,the main research work and achievements in this thesis are as follow:1.The image preproeess methods related to spectra are discussed, including image scale, crop, grayscale,binary,and edge detection.These are convenient for the unified treatment of spectra and efficient extraction of features.2.The features of spectra in such aspects as color, texture shape and space are analyzed concretely, color moments, gray level-gradient co-occurrence matrix and Pseudo-Zernike moments and so on are extracted by MATLAB programming.3.Using the method of Iterative Self-Organizing Data Analysis Techniques Algorithm cluster analysis to achieve the further optimal selection of features.4. The image comparability is indicated by calculating the correlation coefficient of engenvector, which can realize image retrieval by this.5. A software of the assessment of the severity of partial discharge in GIS based on the features of spectra is developed finally, and the accuracy of the system is verified by physical experiments of bad contact of high voltage electrode discharge model, fault of high voltage electrode discharge model and fixed metal particle on the surface of insulator discharge model.