Double Optical Fiber Temperature Compensation Method for Measurement of Interface Pressure Between Simulated Cable and Accessory at High Temperatures

Reliable interface pressure between cables and accessories is closely associated with the safe operation of a power cable system. Using an external optical fiber Bragg grating (FBG) temperature-compensating curvature sensor, a new method for online measurement of the interface pressure between a cable and an accessory at high temperatures is proposed. On the basis of the sensing principle of an FBG, a mathematical pure bending model, and a model of a thick-walled cylinder, an FBG temperature-compensating curvature sensor is fabricated using the Dow Corning Sylgard-184 silicone rubber. The interface pressures of 10-kV cable accessories with different expansion rates at different temperatures are measured. The results of the measurements show that the temperature-compensated deviation of wavelength measurements made by the fiber grating curvature sensor ranges from −2.59% to 5.50%. The interface pressure between the cable and the accessory gradually increases with an increase in temperature from 30 °C to 60 °C. The results are consistent with the results of measurements made using a traditional piezoelectric sensor. This method is expected to evaluate the long-term reliability of the interface pressure of cable accessories in actual complex-temperature environments.