Research on Interface Pressure Measurement Technology of High-Voltage Cable Accessories Based on Nonlinear Ultrasound

Interfacial pressure is a core factor affecting the operational performance of cable accessories. In this study, the interfacial pressure is evaluated by ultrasonic nonlinear detection technique, and the regulation mechanism of pressure on the silicone rubber cable contact state is revealed based on the finite element model. The correlation law between interface pressure and acoustic response is elucidated by establishing a theoretical model of contact acoustic nonlinearity. The results show that an increase in interface pressure enhances the true contact area and contact stiffness, leading to a decrease in the fundamental and second harmonic amplitudes of the interface echo, while the nonlinear coefficients increase monotonically with the increase in pressure. The strong correlation between the contact stiffness and nonlinear coefficients verifies the feasibility of inverting the interface micromorphology by acoustic nonlinear features. The study provides the theoretical support of ultrasonic nonlinear detection technology for the pressure monitoring of high-voltage cable terminal interfaces, which is of guiding significance for engineering applications.