Estimation of Interfacial Temperature Rise Characteristic of Composite Insulator based on Inversion Calculation Method

The conventional infrared temperature measurement technology can only acquire the surface temperature rise characteristics of faulty composite insulators, yet it fails to thoroughly examine the heating characteristics of the interface between the insulator sheathing and mandrel. To address this issue, we devised a temperature inversion calculation method for the interface based on the conjugate gradient method. Firstly, the structure of the composite insulator was streamlined, and a temperature inversion calculation model at the interface was established via a one-dimensional heat transfer structure. The fundamental flow of inversion calculation was also provided. Subsequently, the inversion calculation method was utilized to determine the interfacial temperature of composite insulators by setting material parameters; the results were compared with the measured values, corroborating the accuracy of the inversion method. Thereafter, physical models of composite insulators featuring three typical interface defects including air gaps, iron filings, and perforation were constructed. The surface infrared temperature rise characteristics of these physical models were measured during voltage application, and the temperature distribution at the interface was gleaned based on the inversion calculation method. Lastly, the interfacial heating characteristics of diverse defects at varying positions were compared and analyzed. It was proven that the inversion calculation method of interface temperature holds significant technical value in studying the heating mechanism of defects at the interface of composite insulators.