Study On Detection Method Of Ceramic Insulator Contamination Based On Microwave Radiation Theory

Power system pollution flashover occurs frequently, and the loss is enormous. Insulator surface contamination monitoring the situation can be effective early warning and guidance to line maintenance. For detection of insulator contamination has been a hot and difficult topic. According to microwave radiation theory, in this paper, the insulator contamination detection technologies and methods is researched systematic, and the major jobs and innovations are made as follows:1. A microwave radiation measurement method to detect insulator contamination is proposed. A formula to calculate antenna temperature of insulator contamination and inversion formula of brightness temperature are derived theoretically, the theoretical and technical implementation is determined.2. A model of the brightness temperature of radiation contamination is proposed. The model parameters are analysised. These parameters include the emission rate, contamination layer thickness, insulator material, operating frequency, polarization, and angle measurement. The relationship between brightness temperature and ESDD and the relationship between complex dielectric constant and ESDD are researched. The study shows that the complex dielectric constant of contamination is internal basis to change contamination brightness temperature of radiation. The relationship between ESDD and the complex dielectric constant is studied further by experimental.3. A mathematical model to calculate ESDD/NSDD with brightness temperature is proposed. The model tested by the regression equation is correct. The model shows that relationship between brightness temperature and ESDD/NSDD meet the power function. The ESDD and NSDD can be solved with measurements data under wet and dry conditions. The relationship between the brightness temperature and ESDD or NSDD for XP-70 type is researched by experiment. The results show that the applied high voltage has no direct impact on the antenna temperature, natural and artificial dirty brightness temperature has the same characteristics. The microwave radiation to detecte insulator contamination has a project value.4. An 8mm microwave radiometer has been developed. The radiometer is designed with low-noise of the first circuit and the narrow-beam antenna taking into account the characteristics of insulator contamination. The main performance of linearity, sensitivity, stability and calibration equation meet the needs of measurement.5. A multi-dimensional method for pollution monitoring is proposed. Analysis of the project to detect pollution problems in practice is made. A multidimensional detection method is adopted to reduce the testing error. A technology program of regional contamination detection system is given.