Research On Temperature Rise Distribution Characteristics Of Deteriorated Insulator Strings Based On Infrared Thermography

With the expansion of the scale of the power grid and the continuous improvement of the operating voltage of the power equipment,the insulation performance of the power system decreases as the insulators deteriorate,which leads to the accident of the power system operation.The diagnosis of deteriorated insulators based on infrared thermal imaging technology can achieve non-contact real-time detection.But at present,the infrared detection method based on the temperature rise characteristic of the iron cap has the phenomenon of misdiagnosis and the leakage of the zero value insulators caused by the infrared detection blind area.In order to further excavate the infrared thermal image characteristics of the insulators,the characteristics of the temperature rise distribution of the insulator string surface are included in the identification of the characteristics of the insulators,and the key technologies of the voltage distribution law of the insulator string and the temperature rise distribution of the disk surface,the temperature rise characteristic of the deteriorated insulator,the diagnosis of the blind insulator and so on The problem has been studied in depth.The specific work is as follows:1.According to the simulation analysis of the current insulator string voltage distribution,the influence of insulator surface resistance on the insulator string voltage distribution is not considered in the condition of insulator surface contamination.In this paper,a method of calculating the distribution of insulator string voltage and the temperature rise distribution of the disk surface under the condition of wet pollution is presented.This method is used to distinguish the condition of the drying zone or the dry charged arc on the insulator surface in different positions in the string,and the insulator string voltage distribution model of the insulator's surface resistance in different positions in the string is replaced by the insulator string voltage distribution model..According to the power balance equation in the process of heat exchange,the temperature rise of the disk surface of the insulators in different locations in the series can be solved,and then the temperature rise distribution of the wet insulator string surface is obtained,which lays a theoretical foundation for the excavation of the temperature rise characteristics of the degraded insulator.2.The distribution of the voltage distribution of the wet insulator string and the temperature rise distribution of the disk surface are obtained by using the calculation method of the temperature rise distribution of the wet insulator string surface,and the distribution trend of the temperature rise of the disk surface of the damaged insulator string and the normal insulator string is compared and analyzed.The results show that the size of the surface resistance is an important factor affecting the voltage distribution of insulator string,and the temperature rise of the insulators is different from that of the adjacent normal insulators.The possibility of using the temperature rise distribution of the insulator string surface to identify the insulators' deterioration is present,and the different positions of the insulators are simulated.The trend of heating varies with surface resistivity and deterioration resistance.3.A series of related experiments were carried out in the high pressure artificial contamination test room.The test data showed that under the condition of wet pollution,the deteriorated insulator disc would have the characteristics of low temperature "negative temperature difference",and the degree of "negative temperature difference" of the insulators was affected by the degree of wet pollution,the position in the string,and the deterioration of the insulators.The test results verified the simulation junction.The reasonableness of the fruit.4.Based on the results of simulation and experiment,a method of infrared detection of deteriorated insulators based on the characteristics of iron cap and disk temperature rise is proposed.The method takes the temperature rising characteristics of iron cap as the main feature and the temperature rise characteristic of the disk as auxiliary.The field detection shows that the method can accurately identify and locate the degraded insulators and solve the leakage phenomenon of the blind area insulators caused by the single characteristic quantity.